GUIDELINE Role of endoscopy in the staging and management of colorectal cancer This is one of a series of statements discussing the use PRESURGICAL LOCALIZATION of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society Colonoscopy has an important role in the localization for Gastrointestinal Endoscopy (ASGE) prepared this text. of malignant lesions for subsequent identification at the In preparing this guideline, a search of the medical liter- time of surgery. Preoperative endoscopic marking can be ature was performed by using PubMed. Additional refer- helpful in localizing flat, small, or subtle colonic lesions ences were obtained from the bibliographies of the that may be difficult to identify by inspection or palpation identified articles and from recommendations of expert during surgery. Marking techniques currently available consultants. When limited or no data exist from well- include endoscopic tattooing and metallic clip place- designed prospective trials, emphasis is given to results ment.5-7 Tattoos with India ink are visible at surgery for from large series and reports from recognized experts. up to 5 months.5 No guidelines exist on the optimal Guidelines for appropriate use of endoscopy are based placement of tattoos or metallic clips; therefore, close on a critical review of the available data and expert con- communication with surgical colleagues involved in the sensus at the time that the guidelines are drafted. Further subsequent resection is important. controlled clinical studies may be needed to clarify as- pects of this guideline. This guideline may be revised as necessary to account for changes in technology, new STAGING OF CRC data, or other aspects of clinical practice. The recommen- dations were based on reviewed studies and were graded CRC is staged according to the TNM system established 1 on the strength of the supporting evidence (Table 1). This by the American Joint Committee on Cancer (Table 2).8 guideline is intended to be an educational device The primary clinical impact of staging CRC is to to provide information that may assist endoscopists differentiate T1N0 or T2N0 disease from T3 or TxN1-2 in providing care to patients. This guideline is not disease, for which chemoradiation is recommended in addi- a rule and should not be construed as establishing a tion to surgical resection.9 Several meta-analyses have legal standard of care or as encouraging, advocating, evaluated the staging accuracy of EUS,10-13 and some have requiring, or discouraging any particular treatment. compared the accuracy of EUS with that of magnetic reso- Clinical decisions in any particular case involve a nance imaging (MRI) and CT.10,11 In general, EUS was found ’ complex analysis of the patient s condition and available to exhibit high sensitivity (80%-96%) and specificity (75%- courses of action. Therefore, clinical considerations may 98%) for the staging of T0 to T3 disease.10-13 EUS may have lead an endoscopist to take a course of action that varies higher T-staging accuracy than other cross-sectional imaging from these guidelines. tests,10 but nodal staging accuracy was modest for EUS (67% sensitivity, 78% specificity) and not statistically 10,11 Colorectal cancer (CRC) is the third most commonly different among the 3 imaging modalities. MRI may diagnosed cancer in American men and women and the also have a role in guiding surgery because it shows the an- second leading cause of cancer death.2 This updated atomic relationship between rectal tumors and the pelvic ASGE guideline focuses on the role of endoscopy in the floor and sacrum. Correctly differentiating benign from staging and treatment of CRC. Recommendations for malignant perirectal lymphadenopathy by EUS is difficult CRC screening and surveillance are discussed in previous because inflammatory nodes may be present in the setting documents by the Multi-Society Task Force endorsed by of rectal cancer; however, EUS-guided FNA (EUS-FNA) of the ASGE.3,4 perirectal lymph nodes may be helpful when the presence of nodal metastasis would change patient management.14 The accuracy of EUS may be subject to publication bias and should be viewed with some caution.15 In clinical practice, other imaging modalities may have comparable Copyright ª 2013 by the American Society for Gastrointestinal Endoscopy staging accuracy. A 2011 prospective study of 90 subjects 0016-5107/$36.00 found a T2 staging accuracy of 76% to 77% for both EUS http://dx.doi.org/10.1016/j.gie.2013.04.163 and MRI and T3 staging accuracy of 76% for EUS and 83% 8 GASTROINTESTINAL ENDOSCOPY Volume 78, No. 1 : 2013 www.giejournal.org Role of endoscopy in the staging and management of colorectal cancer TABLE 1. GRADE system for rating the quality of TABLE 2. TNM staging classification of colorectal evidence for guidelines1 cancer Quality of Primary tumor (T) evidence Definition Symbol TX Primary tumor cannot be assessed High quality Further research is very 4444 unlikely to change our T0 No evidence of primary tumor confidence in the Tis Carcinoma in situ: intraepithelial or invasion estimate of effect of lamina propria 444B Moderate quality Further research is likely T1 Tumor invades submucosa to have an important impact T2 Tumor invades muscularis propria on our confidence in the estimate of effect and T3 Tumor invades through the muscularis propria may change the estimate into the subserosa or into nonperitonealized pericolic or perirectal tissues Low quality Further research is 44BB very likely to have an T4 Tumor directly invades other organs or structures important impact on and/or perforates visceral peritoneum our confidence in the Regional lymph nodes (N) estimate of effect and is likely to change the NX Regional lymph nodes cannot be assessed estimate N0 No regional lymph node metastasis Very low quality Any estimate of effect is 4BBB N1 Metastasis in 1-3 regional lymph nodes very uncertain N2 Metastasis in R4 regional lymph nodes Distant metastasis (M) MX Distant metastasis cannot be assessed for MRI (P O .05). MRI did not visualize any T1 tumors, and EUS understaged all T4 tumors in that series.16 The finding M0 No distant metastasis of a nontraversable malignant stricture in the rectum may M1 Distant metastasis be predictive of advanced tumor stage (T3, T4, or Tx, N1 or 2) and should be locally staged by radiographic cross- sectional imaging.17,18 The reported accuracy of EUS restag- ing after neoadjuvant chemoradiation has been modest to surgery after colonic SEMS placement for decompression is poor: 38% to 75% for T staging and 57% to 84% for N stag- 60% to 85%.27 The major adverse events associated with ing.19-25 A prospective study of 90 subjects comparing CT, colonic SEMS placement include obstruction, migration, MRI, and EUS for T and N staging after neoadjuvant therapy and perforation.28 In addition, dilation after colonic SEMS found similarly low accuracy for all 3 modalities. T staging placement should be avoided because of the associated accuracy was 37% by CT, 34% by MRI, and 27% by EUS. N risk of perforation.28 staging was 62% by CT, 68% by MRI, and 65% by EUS. ENDOSCOPIC RESECTION OF COLORECTAL ENDOSCOPIC MANAGEMENT OF MALIGNANT NEOPLASIA COLONIC OBSTRUCTION In general, flat and polypoid lesions found at the time Endoscopic management of malignant obstruction is of colonoscopy should be removed.29 Pedunculated discussed in a recent ASGE Standards of Practice docu- lesions are usually removed by using standard snare ment.26 Endoscopic alternatives to surgical decompression polypectomy. Pedunculated polyps with cancer confined include placement of a self-expandable metal stent (SEMS), to the submucosa and without evidence of unfavorable tumor debulking, and placement of a decompression histological factors have a 0.3% risk of cancer recurrence tube. Even with successful endoscopic decompression, early or lymph node metastasis after complete endoscopic surgical consultation is recommended because patients removal, and surgery is not necessary.30 may deteriorate rapidly. Endoscopy should not be per- For pedunculated polyps with unfavorable histological formed in patients with peritoneal signs or suspicion of per- features (!1 mm cancer-free margin, poor histological dif- foration. Colonic SEMS may also be used as a “bridge to ferentiation, vascular or lymphatic invasion), invading the surgery” for patients with malignant obstruction who are submucosa of the bowel wall below the polyp’s stalk, or ex- surgical candidates. The success rate of single-stage elective tending through the submucosa into the deeper wall www.giejournal.org Volume 78, No. 1 : 2013 GASTROINTESTINAL ENDOSCOPY 9 Role of endoscopy in the staging and management of colorectal cancer layers, surgery is recommended because endoscopic re- polyp tissue include taking a small margin of surrounding moval is unlikely to be curative.31-33 The site of resection mucosa at the polyp edges41 or tissue ablation. Tissue of such polyps should be inked with a tattoo to facilitate ablation has been described both prophylactically at the identification during surgery. In all cases of potential surgi- resection margins after a piecemeal removal and for the cal referral, the risk of recurrent disease should be weighed treatment of endoscopically visible residual polypoid against the operative risk in individual patients. tissue. Ablation techniques have been primarily described Endoscopic removal of larger sessile or flat lesions may with argon plasma coagulation (APC),42-44 with 1 report require more advanced techniques. EMR and endoscopic of diathermy ablation with the snare tip.41 Estimates of submucosal dissection (ESD) are reviewed in a 2008 short-term (2-6 months) residual/recurrence rates after ASGE Technology Status Evaluation Report.34 EMR is piecemeal EMR are broad, ranging from 0% to 55%.45 Late indicated for sessile or flat neoplastic lesions confined to recurrence (after 12 months) is less common, occurring in the mucosa or submucosa of the colon.