Serrated lesions of the colorectum: review and recommendations from an expert panel

Serrated lesions of the colorectum are the precursors of perhaps one-third of colorectal cancers (CRCs). Cancers arising in serrated lesions are usually in the proximal colon, and account for a disproportionate fraction of cancer identified after colonoscopy. We sought to provide guidance for the clinical management of serrated colorectal lesions based on current evidence and expert opinion regarding definitions, classification, and significance of serrated lesions. A consensus conference was held over 2 days reviewing the topic of serrated lesions from the perspectives of histology, molecular biology, epidemiology, clinical aspects, and serrated polyposis. Serrated lesions should be classified pathologically according to the World Health Organization criteria as hyperplastic polyp, sessile serrated adenoma/polyp (SSA/P) with or without cytological dysplasia, or traditional serrated adenoma (TSA). SSA/P and TSA are premalignant lesions, but SSA/P is the principal serrated precursor of CRCs. Serrated lesions have a distinct endoscopic appearance, and several lines of evidence suggest that on average they are more difficult to detect than conventional adenomatous polyps. Effective colonoscopy requires an endoscopist trained in the endoscopic appearance of serrated lesions. We recommend that all serrated lesions proximal to the sigmoid colon and all serrated lesions in the rectosigmoid > 5 mm in size, be completely removed. Recommendations are made for post-polypectomy surveillance of serrated lesions and for surveillance of serrated polyposis patients and their relatives.

Serrated lesions of the colorectum: review and recommendations from an expert panel

Serrated lesions of the colorectum are the precursors of perhaps one-third of colorectal cancers (CRCs). Cancers arising in serrated lesions are usually in the proximal colon, and account for a disproportionate fraction of cancer identified after colonoscopy. We sought to provide guidance for the clinical management of serrated colorectal lesions based on current evidence and expert opinion regarding definitions, classification, and significance of serrated lesions. A consensus conference was held over 2 days reviewing the topic of serrated lesions from the perspectives of histology, molecular biology, epidemiology, clinical aspects, and serrated polyposis. Serrated lesions should be classified pathologically according to the World Health Organization criteria as hyperplastic polyp, sessile serrated adenoma/polyp (SSA/P) with or without cytological dysplasia, or traditional serrated adenoma (TSA). SSA/P and TSA are premalignant lesions, but SSA/P is the principal serrated precursor of CRCs. Serrated lesions have a distinct endoscopic appearance, and several lines of evidence suggest that on average they are more difficult to detect than conventional adenomatous polyps. Effective colonoscopy requires an endoscopist trained in the endoscopic appearance of serrated lesions. We recommend that all serrated lesions proximal to the sigmoid colon and all serrated lesions in the rectosigmoid > 5 mm in size, be completely removed. Recommendations are made for post-polypectomy surveillance of serrated lesions and for surveillance of serrated polyposis patients and their relatives.

Multivisceral resections for rectal cancer

BACKGROUND

En bloc resection of adjacent pelvic organ(s) may be needed to achieve clear surgical margins in rectal cancer surgery. An institutional experience is reported with perioperative morbidity and oncological outcomes.

METHODS

Patients were identified retrospectively from a prospectively collected institutional database (1992-2010). Outcomes, and clinical and pathological factors were determined from medical records. Estimated overall survival, overall recurrence and local recurrence were compared using the log rank method and Cox regression analysis.

RESULTS

Among 1831 patients with rectal cancer, 124 (6·8 per cent) underwent en bloc resection of part or all of an adjacent organ (vagina/uterus/ovary 90, prostate/seminal vesicle 23, bladder/ureter 15, small bowel/appendix 7). Five-year overall survival and local recurrence rates were 53·3 and 18·8 per cent respectively. There was one postoperative death, from multiple organ failure in a patient with liver cirrhosis. Fifty-two patients underwent sphincter-preserving surgery and three (6 per cent) developed an anastomotic leak. On univariable analysis, the only factor associated with local recurrence was completeness of resection (local recurrence rate 15 per cent versus 69 per cent for R0 versus R1 resection; P < 0·001). On multivariable analysis, factors associated with overall survival were sphincter-preserving surgery, absence of metastatic disease and R0 resection.

CONCLUSION

Multiple organ resection for locally advanced primary rectal cancer had good oncological outcomes when clear resection margins were achieved.

Systematic immunohistochemistry screening for Lynch syndrome in early age-of-onset colorectal cancer patients undergoing surgical resection

BACKGROUND

Lynch syndrome (LS), defined by a deleterious (pathogenic) germline mutation in a mismatch repair (MMR) gene, is characterized by early age-of-onset colorectal cancer (CRC). Because clinical criteria for LS, such as the Amsterdam II Criteria, may miss cases, reflex tumor tissue testing of all CRC patients for LS has been proposed. Our study describes the impact of routine immunohistochemistry (IHC) analysis of tumor tissue for loss of MMR protein expression in early age-of-onset CRC patients undergoing resection.

STUDY DESIGN

A prospective institutional program was established to perform IHC analysis on all early age-of-onset (≤50 years) CRC patients undergoing resection. Patients with abnormal IHC analysis were referred to the Clinical Genetics Service for further evaluation. The study cohort excluded patients with other polyposis syndromes and inflammatory bowel disease.

RESULTS

IHC was performed on 198 patients from July 2006 to June 2010. The median age was 42.8 years (range 23.1 to 50.6 years). Abnormal IHC was reported in 38 (19.1%) patients, and 22 (57.8%) with abnormal IHC analysis had germline genetic testing. Seventeen (77.2%) had an alteration detected in an MMR gene: 10 were known to be deleterious mutations and 7 were variants of uncertain significance. Overall, LS was detected in 5.1% of patients. Only 2 of the 10 (20%) with a deleterious mutation actually met the Amsterdam II Criteria.

CONCLUSIONS

Reflex IHC testing for LS on early age-of-onset CRC patients undergoing resection is feasible at the institutional level. This strategy identifies a substantial number of LS patients who would have been missed if genetic testing was based on the Amsterdam II Criteria alone.

Have the changes in treatment of rectal cancer made a significant difference to our patients?

The treatment for patients with locally advanced, resectable rectal cancer has evolved over the years. Various combinations and sequences of chemotherapy, radiation therapy, and total mesorectal excision (TME)-based surgery are the mainstay of current therapy. Preoperative combined chemoradiation, followed by surgery, is now the preferred treatment strategy, with the majority of patients receiving either infusion fluorouracil (5-FU) or capecitabine (Xeloda) with radiation. Clinical trials with oxaliplatin (Eloxatin)-based neoadjuvant chemoradiation have not shown improvement in the pathologic complete response rate (pCR) compared with 5-FU; however, final data addressing local recurrence rates and disease-free survival are pending.The use of adjuvant chemotherapy following preoperative chemoradiation and surgery has not been optimally defined. Some studies have shown that patients who obtained significant pathologic downstaging after chemoradiation and surgery have improved survival with the use of adjuvant chemotherapy. Since FOLFOX (folinic acid, 5-FU, and oxaliplatin) is the preferred adjuvant chemotherapy regimen for stage III colon cancer based on randomized clinical trial results, FOLFOX is also recommended for rectal cancer patients as an adjuvant therapy approach.

Initial experience with transanal endoscopic microsurgery: the need for understanding the limitations

INTRODUCTION

Transanal endoscopic microsurgery is an alternative to transanal excision or radical surgery for benign and carefully selected malignant rectal tumors. Advantages over transanal excision include better visualization, access to more proximal lesions, higher likelihood of negative margins, and lower recurrence rates. Compared to radical resection, patients experience lower rates of morbidity and mortality but may have higher rates of local recurrence.

METHODS

A review of a prospectively maintained database of patients scheduled for transanal endoscopic microsurgery was performed.

RESULTS

Ninety-three patients underwent 96 procedures for 13 carcinoid tumors, 1 submucosal mass, 46 adenomas, 12 in situ adenocarcinomas, and 21 invasive adenocarcinomas. Of these cases, 81.2% was successfully completed. There were nine complications (11.5%). Final pathology demonstrated 33 in situ and invasive adenocarcinomas. The mean follow-up was 25.9 months. The four recurrences (12.1%) occurred in: one tubulovillous adenoma, two in situ carcinomas, and one T2 lesion.

CONCLUSIONS

Transanal endoscopic microsurgery is appropriate for benign lesions such as carcinoid tumors and adenomas and can also be curative in carefully selected patients with early-stage invasive rectal cancer. In cases of invasive adenocarcinoma, it should be reserved for low-risk cancers in patients who accept the possible increased risk of recurrence.

How to manage a patient with multiple adenomatous polyps

Adenomatous polyps are found on screening colonoscopy in 22.5% to 58.2% of the adult population and therefore represent a common problem. Patients with multiple adenomatous polyps are of unique interest because a proportion of these patients have an inheritable form of colorectal cancer. This article discusses the history and clinical features, genetic testing, surveillance, and treatments for the condition.

Identification of patients with high-risk stage II colon cancer for adjuvant therapy

PURPOSE

Adjuvant therapy for Stage II colon cancer remains controversial but may be considered for patients with high-risk features. The purpose of this study was to assess the prognostic significance of commonly reported clinicopathologic features of Stage II colon cancer to identify high-risk patients.

METHODS

We analyzed a prospectively maintained database of patients with colon cancer who underwent surgical treatment from 1990 to 2001 at a single specialty center. We identified 448 patients with Stage II colon cancer who had been treated by curative resection alone, without postoperative chemotherapy.

RESULTS

With median follow-up of 53 months, 5-year disease-specific survival for this cohort was 91 percent. Univariate and multivariate analyses identified three independent features that significantly affected disease-specific survival: tumor Stage T4 (hazard ratio (HR), 2.7; 95 percent confidence interval (CI), 1.1-6.2; P = 0.02), preoperative carcinoembryonic antigen > 5 ng/ml (HR, 2.1; 95 percent CI, 1.1-4.1; P = 0.02), and presence of lymphovascular or perineural invasion (HR, 2.1; 95 percent CI, 1-4.4; P = 0.04). Five-year disease-specific survival for patients without any of the above poor prognostic features was 95 percent; five-year disease-specific survival for patients with one of these poor prognostic features was 85 percent; and five-year disease-specific survival for patients with > or = 2 poor prognostic features was 57 percent.

CONCLUSIONS

Patients with Stage II colon cancer generally have an excellent prognosis. However, the presence of multiple adverse prognostic factors identifies a high-risk subgroup. Use of commonly reported clinicopathologic features accurately stratifies Stage II colon cancer by disease-specific survival. Those identified as high-risk patients can be considered for adjuvant chemotherapy and/or enrollment in investigational trials.

Prognostic implications of the distribution of lymph node metastases in rectal cancer after neoadjuvant chemoradiotherapy

PURPOSE

After preoperative chemoradiotherapy of rectal cancer, the number of retrievable and metastatic lymph nodes is decreased. The current TNM classification is based on number and not location of lymph node metastases and may understage disease after chemoradiotherapy. The aim of this study was to examine the prognostic significance of location of involved lymph nodes in rectal cancer patients after preoperative chemoradiotherapy.

PATIENTS AND METHODS

We prospectively examined whole-mount specimens from 121 patients with uT3-4 and/or N+ rectal cancer who received preoperative chemoradiotherapy followed by resection. Location of involved lymph nodes was compared with median number of lymph nodes involved as well as presence of distant metastasis at presentation.

RESULTS

Lymph node metastases were detected in 37 patients (31%). Thirteen patients with lymph node involvement along major supplying vessels (proximal lymph node metastases) had a significantly higher rate of distant metastatic disease at time of surgery than patients without proximal lymph node involvement (P < .001); median number of lymph nodes involved was two for patients with proximal lymph node metastases and 1.5 for patients with mesorectal lymph node involvement alone.

CONCLUSION

Our data suggest that, after preoperative chemoradiotherapy, proximal lymph node involvement is associated with a high incidence of metastatic disease at time of surgery. Because the median number of involved lymph nodes is low after preoperative chemoradiotherapy, the TNM staging system may not provide an accurate assessment of metastatic disease. Therefore, the ypTNM staging system should incorporate distribution as well as number of lymph node metastases after preoperative chemoradiotherapy for rectal cancer.

Predictive clinicopathologic factors for limited response of T3 rectal cancer to combined modality therapy

PURPOSE

The response of T3 rectal cancer to combined modality therapy (CMT) is highly predictive of long-term outcome following surgery. The aim of this study was to identify pretreatment factors associated with poor tumor response to neoadjuvant chemoradiation.

METHODS

A prospective institutional database at Memorial Sloan-Kettering Cancer Center was queried for endorectal ultrasound (ERUS) stage T3N0-2 rectal cancer patients, treated with CMT followed by surgical resection, between 1998 and 2003. Preoperative clinicopathologic factors determined by biopsy, ERUS, proctoscopy, and digital rectal examination were correlated with the degree of downstaging of the primary mural lesion (tumor downstaging) in response to neoadjuvant therapy. Associations were analyzed by chi-square, Kaplan-Meier, and logistic regression.

RESULTS

Of 274 patients, 51% obtained tumor downstaging in response to preoperative treatment, i.e., lower pathologic T-stage compared with pretreatment ERUS. Five-year recurrence-free survival was 89% in the cohort that obtained tumor downstaging compared with only 45% in the cohort that obtained no tumor downstaging. Factors significantly associated with limited or lack of tumor downstaging after CMT included: fixed tumor on digital rectal examination (p < 0.021), near-circumferential tumor (p < 0.011), tumor stenosis (p < 0.025), metastatic disease (p < 0.012), biopsy-proven poorly differentiated pathology (p < 0.002), and radial extension >2.5 mm on ERUS (p < 0.031). On multivariate analysis, deep radial extension on ERUS, metastatic disease, and poorly differentiated pathology were in each, independently associated with limited or lack of tumor downstaging.

CONCLUSIONS

Pretreatment evaluation with biopsy, proctoscopy, and ERUS can identify T3 rectal cancer patients unlikely to respond well to CMT. These patients may be considered for alternative protocols and their tumors studied to ascertain the molecular events responsible for resistance to chemoradiation.

cT3N0 rectal cancer: potential overtreatment with preoperative chemoradiotherapy is warranted

PURPOSE

Although combined-modality therapy (CMT) is the preferred treatment for T3 and/or lymph node (LN)-positive rectal cancer, the German rectal cancer study published in 2004 demonstrated that 18% of patients deemed suitable for preoperative CMT by endorectal ultrasound (ERUS) may be overstaged. Because data also suggest that LN-negative rectal cancer after total mesorectal excision may not require radiotherapy, it is reasonable to consider omitting radiotherapy for the cT3N0 subset. We therefore determined the accuracy of pre-CMT ERUS or magnetic resonance imaging (MRI) staging, to explore the validity of a nonpreoperative CMT approach for cT3N0 disease.

PATIENTS AND METHODS

One hundred eighty-eight ERUS-/MRI-staged T3N0 rectal cancer patients received preoperative CMT (fluorouracil based and 45-50.4 Gy) followed by radical resection. Rates of pathologic complete response (pCR) and mesorectal LN involvement were determined.

RESULTS

Tumors were located a median of 5 cm from the anal verge. Sphincter-preserving surgery was performed in 143 patients (76%). Overall pCR was 20%, and 41 patients (22%) had pathologically positive mesorectal LNs. The incidence of positive LNs significantly increased with T stage: ypT0, 3%; ypT1, 7%; ypT2, 20%; ypT3-4, 36% (P = .001).

CONCLUSION

The accuracy of preoperative ERUS/MRI for staging mid to distal cT3N0 rectal cancer is limited because 22% of patients have undetected mesorectal LN involvement despite CMT. Therefore, ERUS-/MRI-staged T3N0 rectal cancer patients should continue to receive preoperative CMT. Although 18% may be overstaged and therefore overtreated, our data suggest that an even larger number would be understaged and require postoperative CMT, which is associated with significantly inferior local control, higher toxicity, and worse functional outcome.

Individualized prediction of colon cancer recurrence using a nomogram

PURPOSE

Estimates of recurrence after curative colon cancer surgery are integral to patient care, forming the basis of cancer staging and treatment planning. The categoric staging system of the American Joint Committee on Cancer (AJCC) is commonly used to convey risk by grouping patients based on anatomic elements. Although easy to implement, there remains significant heterogeneity within each stage grouping. In the era of multimodality treatment, a more refined tool is needed to predict recurrence.

METHODS

An institutional database of 1,320 patients with nonmetastatic colon cancer was used to develop a nomogram to estimate recurrence after curative surgery. Prognostic factors were assessed with multivariable analysis using Cox regression, whereas nonlinear continuous variables were modeled with cubic splines. The model was internally validated with bootstrapping, and performance was assessed by concordance index and a calibration curve.

RESULTS

The colon cancer recurrence nomogram predicted relapse with a concordance index of 0.77, improving on the stratification provided by either the AJCC fifth or sixth staging scheme. Factors in the model included patient age, tumor location, preoperative carcinoembryonic antigen, T stage, numbers of positive and negative lymph nodes, lymphovascular invasion, perineural invasion, and use of postoperative chemotherapy.

CONCLUSION

Using common clinicopathologic factors, the recurrence nomogram is better able to account for tumor and patient heterogeneity, thereby providing a more individualized outcome prognostication than that afforded by the AJCC categoric system. By identifying both the high- and low-risk patients within any particular stage, the nomogram is expected to aid in treatment planning and future trial design.

Squamous-cell carcinoma of the anal canal: predictors of treatment outcome

PURPOSE

The incidence of anal canal squamous-cell carcinoma is increasing. Limited data exist on predictors of treatment failure. This study was designed to identify predictors for relapse/persistence after first-line therapy.

METHODS

Using one database, we identified 131 Stages I-III patients treated for primary anal canal squamous-cell carcinoma at our institution from December 1986 to August 2006, with minimum six-month follow-up. Demographic, pathologic, treatment, and outcome data were extracted. Treatment failure was defined as biopsy-proven persistence or relapse (local and/or distant). Univariate, bivariate, and multivariate survival analyses were performed.

RESULTS

Of 131 patients (median age, 58.3 years; median follow-up, 2.9 (range, 0.6-11.2) years), 66 percent were females, 43.5 percent were Stage II, and 11 (8 percent) were HIV-positive. Surgery only (local excision) was uncommon (6.9 percent, n=9). One hundred twenty-two patients (93.1 percent) received radiotherapy; two required preradiotherapy diversion. Although 114 (93.4 percent) completed radiotherapy, most required treatment breaks, making total duration of radiotherapy longer than planned. Almost all patients undergoing radiotherapy (96.7 percent, 118/122) also had chemotherapy: 118 (100 percent, Stages I-III) had concurrent chemotherapy: (98 (83.8 percent) mitomycin/5-fluorouracil, 12 (10.2 percent) cisplatin/5-fluorouracil, 8 (6.8 percent) 5-fluorouracil alone); 35 of 46 (76 percent) Stage III patients received induction chemotherapy (34 (97.1 percent) cisplatin/5-fluorouracil, 1 (2.8 percent) 5-fluorouracil alone). Many (44 percent Stages I/II, 48.9 percent Stage III) required dose adjustments. Thirty-seven patients (28.2 percent) failed first-line therapy. There were no differences between patients with relapse (n=22) or persistence (n=15) of disease. Bivariate analyses demonstrated that T stage (P=0.0019), completion of radiotherapy, and total radiotherapy dose (P=0.03) were all significantly associated with treatment failure. On multivariate analyses, disease stage (P=0.05) and completion of radiotherapy (P=0.01) remained significant predictors of relapse-free survival.

CONCLUSIONS

Tolerance of chemoradiation seems to be an important predictor of treatment success. Effective therapies with less acute toxicity must be identified.

Limitations of early rectal cancer nodal staging may explain failure after local excision

Successful selection of patients with rectal cancer for local excision requires accurate preoperative lymph node staging. Although endorectal ultrasound is capable of detecting locally advanced disease, its ability to correctly identify nodal metastases in early rectal lesions is less well described. This study examines the accuracy of endorectal ultrasound in determining nodal stage based on depth of penetration of the primary lesion (T stage). Between 1998 and 2003, endorectal ultrasound was performed on 938 consecutive patients; 134 had biopsy-proven rectal cancers and were treated with radical resection, without neoadjuvant therapy. Lymph node metastases were measured pathologically and correlated with endorectal ultrasound and clinicopathologic features. Accuracy and specificity of endorectal ultrasound nodal staging was determined. The overall accuracy of endorectal ultrasound nodal staging for the study cohort was 70 percent, with a 16 percent false-positive rate and 14 percent false-negative rate. Endorectal ultrasound was more likely to overlook small metastatic lymph node deposits. The size of lymph node metastasis and accuracy of endorectal ultrasound nodal staging was related to T stage. The specificity of endorectal ultrasound nodal staging, or the ability to identify patients who were node-negative, was dependent on T stage. Early rectal lesions are more likely to have lymph node micrometastases not detected by endorectal ultrasound. The ability of endorectal ultrasound to correctly identify patients without lymph node metastasis is dependent on the T stage of the primary lesion. The limitations of endorectal ultrasound in accurately staging nodal disease in early rectal lesions may, in part, explain the relatively high recurrence rates seen after local excision.

Positron Emission Tomography Detection of Distant Metastatic or Synchronous Disease in Patients with Locally Advanced Rectal Cancer Receiving Preoperative Chemoradiation

BACKGROUND

Patients with locally advanced rectal cancer may present with synchronous distant metastases. Choice of optimal treatment--neoadjuvant chemoradiation versus systemic chemotherapy alone--depends on accurate assessment of distant disease. We prospectively evaluated the ability of [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) to detect distant disease in patients with locally advanced rectal cancer who were otherwise eligible for combined modality therapy (CMT).

METHODS

Ninety-three patients with locally advanced rectal cancer underwent whole-body [18F]FDG PET scanning 2-3 weeks before starting CMT. Sites other than the rectum, mesorectum, or the area along the inferior mesenteric artery were considered distant and were divided into nine groups: neck, lung, mediastinal lymph node (LN), abdomen, liver, colon, pelvis, peripheral LN, and soft tissue. Two nuclear medicine physicians blinded to clinical information used PET images and a five-point scale (0-4) to determine certainty of disease. A score greater than 3 was considered malignant. Confirmation was based on tissue diagnosis, surgical exploration, and subsequent imaging.

RESULTS

At a median follow-up of 34 months, the overall accuracy, sensitivity, and specificity of PET in detecting distant disease were 93.7%, 77.8%, and 98.7% respectively. Greatest accuracy was demonstrated in detection of liver (accuracy = 99.9%, sensitivity = 100%, specificity = 98.8%) and lung (accuracy = 99.9%, sensitivity = 80%, specificity = 100%) disease; PET detected 11/12 confirmed malignant sites in liver and lung. A total of 10 patients were confirmed to have M1 stage disease. All 10 were correctly staged by pre-CMT PET; abdominopelvic computed tomography (CT) scans accurately detected nine of them.

CONCLUSION

Baseline PET in patients with locally advanced rectal cancer reliably detects metastatic disease in liver and lung. PET may play a significant role in defining extent of distant disease in selected cases, thus impacting the choice of neoadjuvant therapy.