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BACKGROUND: Total mesorectal excision (TME) is reported to reduce local recurrence and improve survival rates in patients with carcinoma of the rectum. STUDY DESIGN: Two hundred forty-six consecutive patients with Dukes' B (T3, N0, M0) and C (T(any), N1-2, M0) primary rectal carcinomas underwent operation according to the principle of TME. Kaplan-Meier estimates of survival and pelvic recurrence rates were calculated from a database of patients followed prospectively. RESULTS: The operative mortality rate was 0.8 percent (two of 246). The Kaplan-Meier five-year survival rate for patients with stages B and C was 74.2 percent; for patients with stage T3, N0, M0, 86.7 percent; for patients with stage T(any), N1-2, M0, 64.0 percent; and for patients with substage T3, N1-2, M0, 68.0 percent. Pelvic recurrences were observed in a total of 18 patients (7.3 percent) with or without metastases. In the 246 patients with Dukes' stages B and C, pelvic recurrence rates were 4.0 and 8.1 percent, respectively, in the presence or absence of distant metastases, and 3.0 and 5.8 percent, respectively, in the absence of distant spread. Statistically significant risk factors for pelvic recurrence were N2 disease and perineural invasion. Adjuvant radiation therapy was of no statistical benefit in preventing local recurrences. CONCLUSIONS: Total mesorectal excision cures carcinoma of the rectum and provides excellent local control through resection of the entire unit of regional spread that is excised, intact and with negative circumferential margins. Total mesorectal excision is compatible with autonomic nerve preservation and with sphincter preservation. The current role of combined modality adjuvant therapy, which is standard therapy following conventional surgery, should be reconsidered in patients who have undergone resection in accordance with TME.

Hepatic resection is the treatment of choice for a solitary metastatic deposit from a primary carcinoma of the large intestine in the absence of extrahepatic disease. This study was done to evaluate hepatic resection in the treatment of multiple hepatic metastases from carcinoma of the colon and rectum. Sixty-two patients underwent hepatic resection with an over-all operative mortality of 10 per cent, but a recent (1968-1981) mortality of 2 per cent. Three, five and ten year survival rates were 50, 34 and 21 per cent, respectively. No significant differences in survival patterns were noted comparing site (colon versus rectum), time interval from diagnosis of the primary to diagnosis of metastases (synchronous versus metachronous), sex (male versus female), size of the metastatic lesion (less than 5 centimeters versus greater than or equal to 5 centimeters) or number of metastatic lesions (single versus multiple). The pathologic stage of the primary carcinoma of the large intestine significantly (p less than 0.05) influenced survival patterns after hepatic resection with Dukes' B primary tumor having a median survival time of 123 months versus 27 months for patients with Dukes' C primary tumor. Sixty-seven per cent of those with a recurrence did so within the liver. Adjuvant chemotherapy had no demonstrable effect on survival patterns. Further improvement in survival statistics will require more sensitive staging procedures and effective adjuvant therapy, particularly for patients with Dukes' C primary carcinoma of the large intestine.

The Organ Injury Scaling (O.I.S.) Committee of the American Association for the Surgery of Trauma (A.A.S.T.) has been charged to devise injury severity scores for individual organs to facilitate clinical research. Our first report (1) addressed O.I.S.'s for the Spleen, Liver, and Kidney; the following are proposed O.I.S.'s for Pancreas (Table I), Duodenum (Table II), Small Bowel (Table III), Colon (Table IV), and Rectum (Table V). The grading scheme is fundamentally an anatomic description, scaled from 1 to 5, representing the least to the most severe injury. We emphasize that these O.I.S.'s represent an initial classification system which must undergo continued refinement as clinical experience dictates.

The technique using the EEA stapler for low anterior resection of the rectum has been modified to permit a low anastomosis that can be done with greater facility and safety. The method eliminates the bulky puckering of the ampullary purse string and avoids the disadvantage of joining segments of bowel of different sizes. It also decreases intraoperative contamination and minimizes chances for sepsis. Additionally, it affords an opportunity to check the integrity of the anastomosis. Success of the method seems to document the safety of stapling across a staple line. Results of this method used in a small group of patients are encouraging.

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The College of American Pathologists offers these protocols to assist pathologists in providing clinically useful and relevant information when reporting results of surgical specimen examinations. The College regards the reporting elements in the "Surgical Pathology Cancer Case Summary (Checklist)" portion of the protocols as essential elements of the pathology report. However, the manner in which these elements are reported is at the discretion of each specific pathologist, taking into account clinician preferences, institutional policies, and individual practice.The College developed these protocols as an educational tool to assist pathologists in the useful reporting of relevant information. It did not issue the protocols for use in litigation, reimbursement, or other contexts. Nevertheless, the College recognizes that the protocols might be used by hospitals, attorneys, payers, and others. Indeed, effective January 1, 2004, the Commission on Cancer of the American College of Surgeons mandated the use of the checklist elements of the protocols as part of its Cancer Program Standards for Approved Cancer Programs. Therefore, it becomes even more important for pathologists to familiarize themselves with these documents. At the same time, the College cautions that use of the protocols other than for their intended educational purpose may involve additional considerations that are beyond the scope of this document.This protocol applies to all primary carcinomas of the colon and rectum. Well-differentiated neuroendocrine neoplasms (carcinoid tumors) are not included. The seventh edition TNM staging system for carcinoma of the colon and rectum of the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC) is recommended.Select a Single Response Unless Otherwise Indicated* Data elements with asterisks are not required. However, these elements may be clinically important but are not yet validated or regularly used in patient management.Tumor Site (note A)__ Cecum__ Right (ascending) colon__ Hepatic flexure__ Transverse colon__ Splenic flexure__ Left (descending) colon__ Sigmoid colon__ Rectum__ Other (specify): ______ Not specified*Specimen Integrity*__ Intact*__ Fragmented*Polyp Size* Greatest dimension: __ cm* Additional dimensions: __ × __ cm*__ Cannot be determined (see Comment)*Polyp Configuration*__ Pedunculated with stalk * Stalk length: __ cm*__ SessileSize of Invasive CarcinomaGreatest dimension: __ cm* Additional dimensions: __ × __ cm__ Cannot be determined (see Comment)Histologic Type (note B)__ Adenocarcinoma__ Mucinous adenocarcinoma__ Signet-ring cell carcinoma__ Small cell carcinoma__ Squamous cell carcinoma__ Adenosquamous carcinoma__ Medullary carcinoma__ Undifferentiated carcinoma__ Other (specify): ______ Carcinoma, type cannot be determinedHistologic Grade (note C)__ Not applicable__ Cannot be determined__ Low grade (well differentiated to moderately differentiated)__ High grade (poorly differentiated to undifferentiated)Microscopic Tumor Extension (note D)__ Cannot be determinedInvasion (deepest): __ Lamina propria __ Muscularis mucosae __ Submucosa __ Muscularis propriaMargins (select all that apply)Deep Margin (Stalk Margin)__ Cannot be assessed__ Uninvolved by invasive carcinoma Distance of invasive carcinoma from margin: __ mm__ Involved by invasive carcinomaMucosal/Lateral Margin__ Not applicable__ Cannot be assessed__ Uninvolved by invasive carcinoma__ Involved by invasive carcinoma__ Involved by adenomaLymph-Vascular Invasion (notes D and E)__ Not identified__ Present__ Indeterminate*Type of Polyp in Which Invasive Carcinoma Arose (note F)*__ Tubular adenoma*__ Villous adenoma*__ Tubulovillous adenoma*__ Traditional serrated adenoma*__ Sessile serrated adenoma*__ Hamartomatous polyp*__ Indeterminate*Additional Pathologic Findings (select all that apply)*__ None identified*__ Inflammatory bowel disease *__ Active *__ Quiescent*__ Other (specify): ____*Ancillary Studies* Specify: ____*__ Not performed*Comment(s): ____Select a Single Response Unless Otherwise Indicated* Data elements with asterisks are not required. However, these elements may be clinically important but are not yet validated or regularly used in patient management.Specimen (select all that apply) (note A)__ Terminal ileum__ Cecum__ Appendix__ Ascending colon__ Transverse colon__ Descending colon__ Sigmoid colon__ Rectum__ Anus__ Other (specify): ______ Not specifiedProcedure__ Right hemicolectomy__ Transverse colectomy__ Left hemicolectomy__ Sigmoidectomy__ Rectal/rectosigmoid colon (low anterior resection)__ Total abdominal colectomy__ Abdominoperineal resection__ Transanal disk excision (local excision)__ Other (specify): ______ Not specified*Specimen Length (if applicable)* Specify: __ cmTumor Site (select all that apply) (note A)__ Cecum__ Right (ascending) colon__ Hepatic flexure__ Transverse colon__ Splenic flexure__ Left (descending) colon__ Sigmoid colon__ Rectosigmoid__ Rectum__ Colon, not otherwise specified__ Cannot be determined (see Comment)Tumor SizeGreatest dimension: __ cm* Additional dimensions: __ × __ cm__ Cannot be determined (see Comment)Macroscopic Tumor Perforation (note G)__ Present__ Not identified__ Cannot be determined*Macroscopic Intactness of Mesorectum (note H)*__ Not applicable*__ Complete*__ Near complete*__ Incomplete*__ Cannot be determinedHistologic Type (note B)__ Adenocarcinoma__ Mucinous adenocarcinoma__ Signet-ring cell carcinoma__ Small cell carcinoma__ Squamous cell carcinoma__ Adenosquamous carcinoma__ Medullary carcinoma__ Undifferentiated carcinoma__ Other (specify): ______ Carcinoma, type cannot be determinedHistologic Grade (note C)__ Not applicable__ Cannot be assessed__ Low grade (well differentiated to moderately differentiated)__ High grade (poorly differentiated to undifferentiated)__ Other (specify): ____*Histologic Features Suggestive of Microsatellite Instability (note I)*Intratumoral Lymphocytic Response (tumor-infiltrating lymphocytes)*__ None*__ Mild to moderate (0–2 per high-power [×400] field)*__ Marked (3 or more per high-power field)*Peritumor Lymphocytic Response (Crohn-like response)*__ None*__ Mild to moderate*__ Marked*Tumor Subtype and Differentiation (select all that apply)*__ Mucinous tumor component (specify percentage: __)*__ Medullary tumor component*__ High histologic grade (poorly differentiated)Microscopic Tumor Extension__ Cannot be assessed__ No evidence of primary tumor__ Intramucosal carcinoma, invasion of lamina propria__ Tumor invades submucosa__ Tumor invades muscularis propria__ Tumor invades through the muscularis propria into the subserosal adipose tissue or the nonperitonealized pericolic or perirectal soft tissues but does not extend to the serosal surface__ Tumor penetrates to the surface of the visceral peritoneum (serosa)__ Tumor is adherent to other organs or structures (specify: ____)__ Tumor directly invades adjacent structures (specify: ____)__ Tumor penetrates to the surface of the visceral peritoneum (serosa) and directly invades adjacent structures (specify: ____)Margins (select all that apply) (note J)Proximal Margin__ Cannot be assessed__ Uninvolved by invasive carcinoma__ Involved by invasive carcinoma__ Intramucosal carcinoma/adenoma not identified at proximal margin__ Intramucosal carcinoma/adenoma present at proximal marginDistal Margin__ Cannot be assessed__ Uninvolved by invasive carcinoma__ Involved by invasive carcinoma__ Intramucosal carcinoma/adenoma not identified at distal margin__ Intramucosal carcinoma/adenoma present at distal marginCircumferential (Radial) or Mesenteric Margin__ Not applicable__ Cannot be assessed__ Uninvolved by invasive carcinoma__ Involved by invasive carcinoma (tumor present 0– 1 mm from margin)If all margins uninvolved by invasive carcinoma: Distance of invasive carcinoma from closest margin: __ mm or __ cm Specify margin: __Lateral Margin (for noncircumferential transanal disk excision)__ Cannot be assessed__ Uninvolved by invasive carcinoma Distance of invasive carcinoma from closest lateral margin: __ mm * Specify location (eg, o'clock position), if possible: ______ Involved by invasive carcinoma * Specify location (eg, o'clock position), if possible: ______ Uninvolved by adenoma__ Involved by adenomaTreatment Effect (applicable to carcinomas treated with neoadjuvant therapy) (note K)__ No prior treatment__ Present *__ No residual tumor (complete response, grade 0) *__ Moderate response (grade 1, minimal residual cancer) *__ Minimal response (grade 2)__ No definite response identified (grade 3, poor response)__ Not knownLymph-Vascular Invasion (note E)__ Not identified__ Present__ IndeterminatePerineural Invasion (note E)__ Not identified__ Present__ IndeterminateTumor Deposits (Discontinuous Extramural Extension)(note L)__ Not identified__ Present__ Indeterminate*Type of Polyp in Which Invasive Carcinoma Arose (note F)*__ None identified*__ Tubular adenoma*__ Villous adenoma*__ Tubulovillous adenoma*__ Traditional serrated adenoma*__ Sessile serrated adenoma*__ Hamartomatous polyp*__ IndeterminatePathologic Staging (pTNM) (note M)TNM Descriptors (required only if applicable) (select all that apply)__ m (multiple primary tumors)__ r (recurrent)__ y (posttreatment)Primary Tumor (pT)__ pTX: Cannot be assessed__ pT0: No evidence of primary tumor__ pTis: Carcinoma in situ, intraepithelial (no invasion)__ pTis: Carcinoma in situ, invasion of lamina propria__ pT1: Tumor invades submucosa__ pT2: Tumor invades muscularis propria__ pT3: Tumor invades through the muscularis propria into pericolorectal tissues__ pT4a: Tumor penetrates the visceral peritoneum__ pT4b: Tumor directly invades or is adherent to other organs or structuresRegional Lymph Nodes (pN)__ pNX: Cannot be assessed__ pN0: No regional lymph node metastasis__ pN1a: Metastasis in 1 regional lymph node__ pN1b: Metastasis in 2 to 3 regional lymph nodes__ pN1c: Tumor deposit(s) in the subserosa, or nonperitonealized pericolic or perirectal tissues without regional lymph node metastasis__ pN2a: Metastasis in 4 to 6 regional lymph nodes__ pN2b: Metastasis in 7 or more regional lymph nodesSpecify: Number examined: __ Number involved: __Distant Metastasis (pM)__ Not applicable__ pM1: Distant metastasis * Specify site(s): ______ pM1a: Metastasis to single organ or site (eg, liver, lung, ovary, nonregional lymph node)__ pM1b: Metastasis to more than one organ/site or to the peritoneum*Additional Pathologic Findings (select all that apply)*__ None identified*__ Adenoma(s)*__ Chronic ulcerative proctocolitis*__ Crohn disease*__ Dysplasia arising in inflammatory bowel disease*__ Other polyps (type[s]): ____*__ Other (specify): ____*Ancillary Studies (select all that apply) (note N)*__ Microsatellite instability (specify testing method: ____) *__ Stable *__ Low *__ High* Immunohistochemistry Studies for Mismatch Repair Proteins *__ MLH1 *__ Intact nuclear positivity, tumor cells *__ Loss of nuclear positivity, tumor cells *__ Pending *__ Other (specify): ____ *__ MSH2 *__ Intact nuclear positivity, tumor cells *__ Loss of nuclear positivity, tumor cells *__ Pending *__ Other (specify): ____ *__ MSH6 *__ Intact nuclear positivity, tumor cells *__ Loss of nuclear positivity, tumor cells *__ Pending *__ Other (specify): ____ *__ PMS2 *__ Intact nuclear positivity, tumor cells *__ Loss of nuclear positivity, tumor cells *__ Pending *__ Other (specify): ____*__ BRAF V600E mutational analysis (specify testing method: ____) *__ Mutant BRAF detected *__ No mutant BRAF detected (wild-type BRAF allele) *__ Other (specify): ____*__ KRAS mutational analysis (specify testing method: ____) *__ Mutant KRAS detected (specify mutation ____) *__ No mutant KRAS detected (wild-type KRAS allele) *__ Other (specify): ____Other, specify: ____*__ Not performed*Comment(s): ____The protocol applies to all carcinomas arising in the colon and rectum.1 It excludes carcinomas of the vermiform appendix and low-grade neuroendocrine neoplasms (carcinoid tumors).The colon is divided as shown in Figure 1. The right colon is subdivided into the cecum and the ascending colon.2 The left colon is subdivided into the descending colon and sigmoid colon (see Table).1The transition from sigmoid to rectum is marked by the fusion of the tenia coli of the sigmoid to form the circumferential longitudinal muscle of the rectal wall approximately 12 to 15 cm from the dentate line. The rectum is defined clinically as the distal large intestine commencing opposite the sacral promontory and ending at the anorectal ring, which corresponds to the proximal border of the puborectalis muscle palpable on digital rectal examination1 (Figure 2). When measuring below with a rigid sigmoidoscope, it extends 16 cm from the anal verge.Tumors located at the border between 2 subsites of the colon (eg, cecum and ascending colon) are registered as tumors of the subsite that is more involved. If 2 subsites are involved to the same extent, the tumor is classified as an "overlapping" lesion.A tumor is classified as rectal if its inferior margin lies less than 16 cm from the anal verge or if any part of the tumor is located at least partly within the supply of the superior rectal artery.3 A tumor is classified as rectosigmoid when differentiation between rectum and sigmoid according to the previously mentioned guidelines is not possible.4For consistency in reporting, the histologic classification proposed by the World Health Organization (WHO) is recommended and follows.5AdenocarcinomaMucinous (colloid) adenocarcinoma (greater than 50% mucinous)Signet-ring cell carcinoma (greater than 50% signet-ring cells)*Squamous cell carcinomaAdenosquamous carcinomaMedullary carcinoma†Small cell carcinoma# (high-grade neuroendocrine carcinoma)Undifferentiated carcinoma*Other (specify)‡* By convention, signet-ring cell carcinomas, small cell carcinomas, and undifferentiated carcinomas are high grade (see note C). The only histologic types of colorectal carcinoma that have been shown to have adverse prognostic significance independent of stage are signet-ring cell carcinoma6 and small cell carcinoma (high-grade neuroendocrine carcinoma).7† Medullary carcinoma is a distinctive histologic type strongly associated with high levels of microsatellite instability (MSI-H), indicative of defects in normal DNA repair gene function. Medullary carcinoma may occur either sporadically8 or in association with hereditary nonpolyposis colon cancer (HNPCC).9 This tumor type is characterized by solid growth in nested, organoid, or trabecular patterns, with no immunohistochemical evidence of neuroendocrine differentiation. Medullary carcinomas are also characterized by numerous tumor infiltrating lymphocytes (see note I).‡ The term "carcinoma, NOS" (not otherwise specified) is not part of the WHO classification.A number of grading systems for colorectal cancer have been suggested, but a single widely accepted and uniformly used standard for grading is lacking. Most systems stratify tumors into 3 or 4 grades as follows:Grade 1: Well differentiatedGrade 2: Moderately differentiatedGrade 3: Poorly differentiatedGrade 4: UndifferentiatedDespite a significant degree of interobserver variability,10 histologic grade has repeatedly been shown by multivariate analysis to be a stage-independent prognostic factor.11 Specifically, it has been demonstrated that high tumor grade is an adverse prognostic factor. It is noteworthy that in most studies documenting the prognostic power of tumor grade, the number of grades has been collapsed to produce a 2-tiered stratification for data analysis as follows:Low grade: Well differentiated and moderately differentiatedHigh grade: Poorly differentiated and undifferentiatedThe widest variations in grading concern the stratification of low-grade tumors into well- or moderately differentiated categories, while interobserver variability in diagnosing high-grade carcinoma is relatively small. Therefore, in light of its proven prognostic value, relative simplicity, and reproducibility, a 2-tiered grading system for colorectal carcinoma (ie, low grade and high grade) is recommended. The following criteria for grading based on gland formation alone are suggested12:Low grade: Greater than or equal to 50% gland formationHigh grade: Less than 50% gland formationColorectal adenomas containing invasive adenocarcinoma that extends through the muscularis mucosae into the submucosa have been defined as "malignant polyps."13 This term encompasses cases in which the entire polyp head is replaced by carcinoma and adenomas with focal malignancy, but the definition excludes adenomas with high-grade dysplasia (intraepithelial carcinoma) or intramucosal carcinoma (invasive carcinoma limited to the lamina propria or invading no deeper than the muscularis mucosae) because these polyps possess negligible biologic potential for metastasis14 (see Tis in note M).Malignant polyps removed by endoscopic polypectomy require evaluation of histologic factors related to the risk of adverse outcome (ie, lymph node metastasis or local recurrence from residual malignancy) following polypectomy.1315 Factors shown to have independent prognostic significance and are important in determining the need for further surgical treatment include:An increased risk of adverse outcome has been shown to be associated with:Venous invasion has been demonstrated by multivariate analysis to be an independent adverse prognostic factor.11 Invasion of extramural veins, in particular, has been shown to be an independent indicator of unfavorable outcome and increased risk of occurrence of hepatic metastasis.16 The significance of intramural venous invasion is less clear, because data specific to this issue are lacking.In several studies, both lymphatic invasion17 and perineural invasion18 have been shown by multivariate analysis to be independent indicators of poor prognosis. The prognostic significance, if any, of the anatomic location of these structures is not defined. Furthermore, it is not always possible to distinguish lymphatic vessels from postcapillary venules because both are small, thin-walled structures. Thus, the presence or absence of tumor invasion of small, thin-walled vessels should be reported in all cases.Distinction should be made between traditional serrated adenomas, which exhibit cytologic features of adenomas, and the newly described sessile serrated adenomas.19 The sessile serrated adenoma may be the precursor lesion for colorectal carcinomas with MSI-H; they are more commonly found in the right colon and are characterized by serrated architecture with bulbous dilatation of deep crypts and lack of overt nuclear atypia, in most cases.Tumor perforation is an uncommon complication of colorectal cancer, but one that is associated with a poor outcome, including high in-hospital mortality and morbidity.20 Perforation of the uninvolved colon proximal to an obstructing tumor is also associated with high mortality because of generalized peritonitis and sepsis. Reported perforation rates range from 2.6% to 9%. Perforation is more likely to occur in older patients.The quality of the surgical technique is a key factor in the success of surgical treatment for rectal cancer, both in the prevention of local recurrence and in long-term survival. Numerous studies have demonstrated that total mesorectal excision (TME) improves local recurrence rates and the corresponding survival by as much as 20%. This surgical technique entails precise sharp dissection within the areolar plane outside (lateral to) the visceral mesorectal fascia to remove the rectum. This plane encases the rectum, its mesentery, and all regional nodes and constitutes Waldeyer fascia. High-quality TME surgery reduces local recurrence from 20% to 30%, to 8% to 10% or less, and increases 5-year survival from 48% to 68%.2122 Adjuvant therapy in the presence of a high-quality TME may further reduce local recurrence (from 8% to 2.6%).22Pathologic evaluation of the resection specimen has been shown to be a sensitive means of assessing the quality of rectal surgery. It is superior to indirect measures of surgical quality assessment, such as perioperative mortality, rates of complication, number of local recurrences, and 5-year survival. It has been shown that macroscopic pathologic assessment of the completeness of the mesorectum of the specimen, scored as complete, partially complete, or incomplete, accurately predicts both local recurrence and distant metastasis.22 Microscopic parameters, such as the status of the circumferential resection margin, the distance between the tumor and nearest circumferential margin (ie, "surgical clearance"), and the distance between the tumor and the closest distal margin, are all important predictors of local recurrence and may be affected by surgical technique. There is strong evidence that the status of the circumferential resection margin is a powerful predictor of local recurrence but is inconsistently evaluated and underreported.The nonperitonealized surface of the fresh specimen is examined circumferentially, and the completeness of the mesorectum is scored as described in the following.22 The entire specimen is scored according to the worst area.Little bulk to the mesorectumDefects in the mesorectum down to the muscularis propriaAfter transverse sectioning, the circumferential margin appears very irregularModerate bulk to the mesorectumIrregularity of the mesorectal surface with defects greater than 5 mm, but none extending to the muscularis propriaNo areas of visibility of the muscularis propria at the site of the mesorectum with a of the mesorectal surface defects greater than 5 mm in the distal margin of the transverse sectioning, the circumferential margin appears of colorectal tumors is as repair may as a prognostic of patient outcome, a of response to and as a tool for guidelines for testing colorectal tumors for the following cancer in a patient is than of or other tumors and small and tumors and adenomas and of cancer with in a patient is than cancer in 1 or more with an with 1 of the in a than cancer in 2 or more or with of histologic features are defined as presence of cell or growth lymphocytes are associated with and architecture (see and should be from or are the tumor not associated with lymph have not been only and lymphocytes 3 or more per high-power should be pathologic features associated with status in colorectal carcinomas high-grade and lack of may be to the closest to the tumor with following of the serosal surface for and other of tumor marked by should be in the macroscopic of the surgical pathology report. The serosal surface does not a surgical to the proximal and distal the circumferential margin (Figure 3, A through be for any either (Figure 3, or by peritoneum (Figure 3, (see note The circumferential margin the soft tissue margin closest to the of tumor and is by or sharp dissection of the or analysis has that tumor of the circumferential margin is the most factor in local recurrence in rectal A circumferential margin in rectal cancer increases the risk of recurrence by and the risk of from this the circumferential margin should be in all rectal carcinomas as as with nonperitonealized The distance between the tumor and circumferential margin should be reported (see note The circumferential margin is if the tumor is more than 1 mm from the nonperitonealized surface but should be as if tumor is located 1 mm or less from the nonperitonealized surface because local recurrence rates are with of to 1 This assessment tumor within a lymph node as as tumor but if circumferential margin is based on this should be resection margin is the only relevant circumferential margin in by peritoneum (eg, transverse of this margin should be reported even if tumor does not the serosal to the proximal and distal resection margins be either by longitudinal to the margin or by to the The distance from the tumor to the closest resection may also be for low anterior these a distal resection margin of 2 cm is for and 1 cm may be distal are when the distance to the closest transverse margin is 5 cm or cases of carcinoma arising in a of inflammatory bowel proximal and distal resection margins should be evaluated for dysplasia and therapy in rectal cancer is associated with significant tumor response and of the as detected by pathologic of the specimen, is associated with a from neoadjuvant should be with of the tumor Minimal residual disease has been shown to have a than residual several grading systems for tumor response have been a tumor grade has been shown to interobserver with and to prognostic should be only in the primary lymph node should not be in the of in from patient neoadjuvant therapy are to tumor and are not used to stage or as lymph tumor in pericolic or perirectal from the of the tumor and no evidence of residual lymph node but within the lymphatic of the primary carcinoma, are or and are not as lymph nodes replaced by Most are to more perineural these tumor are associated with and their number should be in the surgical pathology report. If tumor are in that otherwise be classified as (tumor to or (tumor to muscularis the primary tumor classification is not but the is in a as (see note resection the most effective therapy for colorectal carcinoma, and the of is from the pathologic on the resection The anatomic of disease is by the most important prognostic factor in colorectal protocol the TNM staging system of the and the but does not the use of other staging convention, the to a primary tumor that has not been previously The to the pathologic classification of the as to the and is based on and entails a resection of the primary tumor or to the entails or of nodes to lymph node and of distant classification is by the treatment evaluation of the patient or when pathologic classification is not of cases of TNM or the and and are

BACKGROUND: The wide global variation in the definition of the rectum has led to significant inconsistencies in trial recruitment, clinical management, and outcomes. Surgical technique and use of preoperative treatment for a cancer of the rectum and sigmoid colon are radically different and dependent on the local definitions employed by the clinical team. A consensus definition of the rectum is needed to standardise treatment. METHODS: The consensus was conducted using the Delphi technique with multidisciplinary colorectal experts from October, 2017 to April, 2018. RESULTS: Eleven different definitions for the rectum were used by participants in the consensus. Magnetic resonance imaging (MRI) was the most frequent modality used to define the rectum (67%), and the preferred modality for 72% of participants. The most agreed consensus landmark (56%) was "the sigmoid take-off," an anatomic, image-based definition of the junction of the mesorectum and mesocolon. In the second round, 81% of participants agreed that the sigmoid take-off as seen on computed tomography or MRI achieved consensus, and that it could be implemented in their institution. Also, 87% were satisfied with the sigmoid take-off as the consensus landmark. CONCLUSION: An international consensus definition for the rectum is the point of the sigmoid take-off as visualized on imaging. The sigmoid take-off can be identified as the mesocolon elongates as the ventral and horizontal course of the sigmoid on axial and sagittal views respectively on cross-sectional imaging. Routine application of this landmark during multidisciplinary team discussion for all patients will enable greater consistency in tumour localisation.

PURPOSE: Several recent reports of high local recurrence and lymph node metastasis in T1 carcinoma of the rectum prompted us to study the risk factors for lymph node metastasis in these lesions. METHODS: We reviewed the clinical records of 7,543 patients who underwent operative treatment for carcinoma of the colon and rectum from 1979 to 1995. Only patients with sessile T1 lesions who underwent colorectal resection were included in the study, yielding an analysis cohort of 353 patients. The following carcinoma-related variables were assessed: size, mucinous subtype, carcinomatous component, grade, site in colon and rectum, lymphovascular invasion, and depth of submucosal invasion. For the depth, the submucosa was divided into upper third (sm1), middle third (sm2), and lower third (sm3). Chi-squared tests and logistic regression were used to evaluate the variables as potential risk factors for lymph node metastasis. RESULTS: The incidence of T1 lesions was 8.6 percent. In the analysis cohort, the lymph node metastasis rate was 13 percent. Significant predictors of lymph node metastasis both univariately and multivariately were sm3 (P = 0.001), lymphovascular invasion (P = 0.005), and lesions in the lower third of the rectum (P = 0.007). Poorly differentiated carcinoma was significant univariately (P = 0.001) but not in the multivariate model. No other parameter was associated with a significant risk. CONCLUSIONS: T1 colorectal carcinomas with lymphovascular invasion, sm3 depth of invasion, and location in the lower third of the rectum have a high risk of lymph node metastasis. These lesions should have an oncologic resection. In a case of the lesion in the lower third of the rectum, local excision plus adjuvant chemoradiation may be an alternative.

OBJECTIVE: The authors' aim was to determine survival and recurrence rates in patients undergoing resection of rectal cancer achieved by abdominoperineal resection (APR), coloanal anastomosis (CAA), and anterior resection (AR) without adjuvant therapy. SUMMARY BACKGROUND DATA: The surgery of rectal cancer is controversial; so, too, is its adjuvant management. Questions such as preoperative versus postoperative radiation versus no radiation are key. An approach in which the entire mesorectum is excised has been proposed as yielding low recurrence rates. METHODS: Of 1423 patients with resected rectal cancers, 491 patients were excluded, leaving 932 with a primary adenocarcinoma of the rectum treated at Mayo. Eighty-six percent were resected for cure. Surgery plus adjuvant treatment was performed in 418, surgery alone in 514. These 514 patients are the subject of this review. Among the 514 patients who underwent surgery alone, APR was performed in 169, CAA in 19, AR in 272, and other procedures in 54. Eighty-seven percent of patients were operated on with curative intent. The mean follow-up was 5.6 years; follow-up was complete in 92%. APR and CAA were performed excising the envelope of rectal mesentery posteriorly and the supporting tissues laterally from the sacral promontory to the pelvic floor. AR was performed using an appropriately wide rectal mesentery resection technique if the tumor was high; if the tumor was in the middle or low rectum, all mesentery was resected. The mean distal margin achieved by AR was 3 +/- 2 cm. RESULTS: Mortality was 2% (12 of 514). Anastomotic leaks after AR occurred in 5% (16 of 291) and overall transient urinary retention in 15%. Eleven percent of patients had a wound infection (abdominal and perineal wound, 30-day, purulence, or cellulitis). The local recurrence and 5-year disease-free survival rates were 7% and 78%, respectively, after AR; 6% and 83%, respectively, after CAA; and 4% and 80%, respectively, after APR. Patients with stage III disease, had a 60% disease-free survival rate. CONCLUSIONS: Complete resection of the envelope of supporting tissues about the rectum during APR, CAA, and AR when tumors were low in the rectum is associated with low mortality, low morbidity, low local recurrence, and good 5-year survival rates. Appropriate "tumor-specific" mesorectal excision during AR when the tumor is high in the rectum is likewise consistent with a low rate of local recurrence and good long-term survival. However, the overall failure rate of 40% in stage III disease (which is independent of surgical technique) means that surgical approaches alone are not sufficient to achieve better long-term survival rates.

Volume One: Principles. Part I: Anatomy & Physiology, M R B Keighley & D Lubowski. Running a Coloproctology Service (To Include Physiology, Imaging, Stomatherapy, And Psychology), M R B Keighley. Mechanical Bowel Preparation, M R B Keighley. Nutritional Care, N S Williams. Sepsis and the Use of Antibiotic Cover in Colorectal Surgery, M R B Keighley. Surgical Principles & Laparoscopy, N S Williams & S Wexner. Anaesthesia for Coloproctology, A Wilkey & P Hutton. Part Ii: Stomas and Related Problems. Ileostomy (& Laparoscopy), M R B Keighley (& S Wexner). Colostomy (& Laparoscopy), M R B Keighlye (& S Wexner). Persistent Perineal Sinus , M R B Keighley. Impaired Sexual Function After Renal Surgery, M R B Keighley. Part Iii: Anal Diseases. Haemorrhoidal Disease. Causes, Natural History and Assessment. History of the Management of Haemorrhoidal Disease. Conservative Management of Haemorrhoidal Disease. Operative Treatment of Haemorrhoidal Disease, N S Williams. Fissure in Ano, M R B Keighley. Hidradenitis Suppurativa, M R B Keighley. Anorectal Abscess, M R B Keighley. Anorectal Fistula, M R B Keighley. Pilonidal Sinus, M R B Keighley. Perianal Warts, M R B Keighley. Pruritus Ani, M R B Keighley. Part Iv: Functional Bowel Disorders. Faecal Incontinence. Aetiology. Investigation. Conventional Treatment. Electrically Stimulated Gracilis Transposition, M R B Keighley and N S Williams. Constipation: Rectocoele & Sigmoidocoele, M R B Keighley and N S Williams. Adult Megacolon & Megarectum, M R B Keighley. Rectal Prolapse (& Laparoscopy), M R B Keighley (& S Wexner). Solitary Rectal Ulcer Syndrome, M R B Keighley. Irritable Bowel Syndrome, M R B Keighley. Chronic Idiopathic Perineal Pain, M R B Keighley and N S Williams. Part V: Precancer and Cancer. The Genetics of Colorectal Neoplasia, S Derudi. Polypoid Disease, N S Williams. Polyposis Syndromes, N S Williams. Colorectal Cancer: Epidemiology, Aetiology, Pathology, Clinical Features and , Diagnosis Screening, N S Williams. Surgical Treatment of Carcinoma in the Colon and Rectum (With Particular Reference to Colon Cancer), N S Williams. Surgical Treatment of Rectal Cancer + Tem, N S Williams. Radiotherapy and Chemotherapy for Primary Colorectal Cancer, Surveillance, And Recurrence, N S Williams. Malignant Tumours of the Anal Canal and Anus, N S Williams. Rare Tumours of the Anal Canal and Anus, N S Williams. Role of Laparoscopy in Neoplasia of the Anus, Rectum and Colon (Fap, , Polyps, Early Ca, Established Ca, Palliation), S Wexner. Volume Two: Inflammatory Bowel Disease. Part Vi: Left-Sided and Right-Sided Colonic Diverticular Disease (& Laparoscopy), M R B Keighley (& S Wexner). Left Sided Dd. Aetiology. Incidence, Associated Factors. Natural History. Clinical Presentation & Investigation. Differential Diagnosis. Treatment. Right Sided. Part Vii: Other Inflammatory Disorders. Miscellaneous Inflammatory Disorders Collagenous Lymphocytic Microcytic Colitis , M R B Keighley and N S Williams. Part Viii: Ulcerative Colitis. Aetiology, Epidemiology and Natural History of Ulcerative Colitis, M R B Keighley. Pathology and Diagnosis and Differential Diagnosis, M R B Keighley. Medical Treatment, M R B Keighley. Ulcerative Proctitus, M R B Keighley. Associated Disorders and Special Management Problems, M R B Keighley. Colorectal Cancer in Ulcerative Colitis, M R B Keighley. Acute Fulminating Colitis and Emergency Colectomy, M R B Keighley. Conventional Proctocolectomy with Ileostomy and Proctectomy Alone in Ulcerative Colitis, M R B Keighley. Subtotal Colectomy and Ileorectal Anastomosisin Ulcerative Colitis, M R B Keighley. Reservoir Ileostomy in Ulcerative Colitis, M R B Keighley. Restorative Proctocolectomy and Ileal Pouch Anal Anastomosis (& Laparoscopy), M R B Keighley (& S Wexner). Crohns Disease. Aetiology, Incidence and Epidemiology, M R B Keighley. Pathology, Diagnosis and Differential Diagnosis, M R B Keighley. Natural History, Morbidity and Mortality, M R B Keighley. Medical Treatment, M R B Keighley. Special Surgical Considerations in Crohns Disease & Roleof Laparoscopy, M R B Keighley & S Wexner. Surgical Treatment of Crohns Disease: General Principles , M R B Keighley. Surgical Treatment of Small Bowel Crohns Disease (& Laparoscopy), M R B Keighley (& S Wexner). Surgical Treatment of Colorectal Crohns Disease ( & Laparoscopy), M R B Keighley (& S Wexner). Surgical Treatment of Perianal Crohns Disease (& Laparoscopy), M R B Keighley (& S Wexner). Part Ix: Laparoscopy for Ibd. Role of Laparoscopy for Inflammatory Bowel Disease, S Wexner. Part X: Emergencies. Large Bowel Obstruction, N S Williams. Injuries to the Colon and Rectal + (Iatrogenic), S Galandiuk. Bleeding from the Colon and Rectum, M R B Keighley. Colonic Ischaemia and Ischaemic Colitis, M R B Keighley. Radiation Injury to Colon and Rectum, N S Williams. Intestinal Fistulas, M R B Keighley. Management of Intra-Abdominal Sepsis Complicating Colorectal Disease, M R B Keighley. Part Xi: Infections. Diarrhoea and Acute Specific Colitis, M R B Keighley. Sexually Transmitted Disease in Coloproctology, L Gotesmann. Tropical Coloproctology, M J G Farthing. Part Xii: Specialist Considerations. Urological Consideration in Coloproctology, C Fowler. Gynaecological Conditions Relevant to the Coloproctological Surgeon, J Shepherd, A Lower & G Jarvis. Part Xiii: Paediatric Coloproctology. Anorectal Agenesis, M Stringer. Hirschprung Disease, M Stringer. Other Paediatric Colorectal Disorders, C Doig. ,

The clinicopathologic significance of mucus production by adenocarcinoma of the colon and rectum was analyzed in retrospective study with stage matched non-mucus producing control carcinomas. Mucinous carcinoma of the colon and rectum comprised 132 (15%) of 893 cases of colorectal carcinoma. The rectum was the most common site (33% of cases). While 120 mucinous cancers had a poorer five-year survival than non-mucinous tumors (34% vs. 53%, p less than .005), these had a particularly bad prognosis in the rectum (18% 5 year survival vs. 49% for the non-mucinous tumor controls, p less than .00k). The theoretical basis for this location-dependent behavior is considered. From this study, distinctive clinico-pathologic features emerge. There were seven documented cases of ulcerative colitis and 8 additional patients gave a history of "colitis". An additional five patients had received prior pelvic irradiation. Of particular note was the fact that 31% of mucinous carcinomas were associated with villous adenomas, implying a histogenetic relationship. Moreover, this finding again emphasizes the neoplastic potential of the villous adenoma, especially in the rectum where the development of mucinous carcinoma is particularly ominous.

Rectal cancer surgery is difficult due to the rectum's relatively inaccessible pelvic position and its direct relation to many vital structures. The surgeon is challenged to restore intestinal continuity while working in a confined space. Despite the importance of these issues, the embryology and surgical anatomy of the rectum have been poorly understood. In recent years, cadaver dissections and operative resection under direct vision have provided a clearer picture of the structure of the rectum and mesorectum, their innervation, blood supply, and surrounding structures. New imaging techniques will shed further light on the anatomy of these structures and their anatomic variations.