SCar-biopsies After Malignant Colorectal Polypectomy of Uncertain RAdicality

After endoscopic removal of a colorectal polyp that harbors (unexpected) adenocarcinoma, pathology usually can not guarantee a radical resection from an oncological point of view. In such case, additional surgical resection is advised. However, only in 15% of patients, residual adenocarcinoma is found. This study investigates the sensitivity of biopsies from the polypectomy scar for residual adenocarcinoma.

Rationale: colorectal polyps may harbor adenocarcinoma. Numbers are increasing due to the nationwide colorectal screening program. After endoscopic removal, rescue surgery is often performed because radicality can not be guaranteed by the pathologist. However, in 85% of surgical specimen no residual malignancy is found. Given morbidity and mortality associated with surgery a method to diagnose residual cancer is needed.

Biopsies from the polypectomy site are variably used to reduce the likelihood of residual tumor at the polypectomy site under these circumstances. However, the sensitivity of such biopsies is unknown.

Objective: to evaluate the sensitivity of second-look endoscopic biopsies from the polypectomy site for residual tumor.

Study design: prospective cross-sectional design using a multi-center approach. Study population: patients planned for rescue surgery for the sole reason of (potentially) irradical endoscopic resection of a colorectal adenocarcinoma without poor differentiation, lymphovascular invasion or tumor budding and without other signs of dissemination.

Intervention: endoscopic biopsies from the polypectomy site before operation. Main study parameters/endpoints: sensitivity of second-look biopsies from the polypectomy site for residual tumor in the resected bowel and postoperative mortality. Various other factors will be assessed that might be associated with residual cancer.

Nature and extent of the burden and risks associated with participation and benefit: Depending on the situation: a): In case a tattoo needs to be done of the polypectomy site, a second endoscopy is done anyway and taking biopsies (painless) will be of no extra burden; b): In case no tattoo needs to be done a sigmoidoscopy (lesion distal to the splenic flexure) or colonoscopy (proximal to the splenic flexure) needs to be arranged for the purpose of this study. A sigmoidoscopy takes 10-20 minutes. Preparation consists of two enemas. A colonoscopy takes 20-30 minutes. Preparation consists of drinking 3 litre of MoviPrep®, both usually doe at home. Notice that the patient has recent experience with colonoscopy. If necessary, both investigations can be arranged under conscious sedation (the rule in colonoscopy), which also implies day-care admission. The risk of complications of a second endoscopy is estimated \< 1:5000. The benefit of a 2nd colonoscopy is the discovery of new polyps in 10-25% of cases.

Eligibility Criteria:
Inclusion Criteria:

* Aged 18 or above.
* Endoscopically removed colorectal lesion with the following pathological characteristics:

  * A moderately-to-well differentiated adenocarcinoma.
  * If possible to judge: distance between adenocarcinoma and vertical or lateral resection margin is less than 1 mm.
  * In case of piecemeal resection: unjudgeable radicality (mostly due to loss of orientation and multiple fragments).
  * Absence of / unjudgeable lymphatic / vascular invasion.
  * No or only grade I tumor budding.
* No suspicion of dissemination on the following investigations: serum carcino-embryonic antigen, a computer tomographic (CT) scan of the abdomen and a chest X-ray; in case of a rectal tumor (less than 15 cm from the anal verge): an additional magnetic resonance imaging of the rectum.
* Operation is advised in agreement with the Dutch Guideline on Colorectal cancer, planned and agreed on by the patient.
* Written informed consent is obtained.

Exclusion Criteria:

* Pathology shows one or more of the following characteristics:

  * A radical en-bloc resection with a free vertical and lateral margin of ≧ 1 mm.
  * A poorly differentiated or signet-cell containing adenocarcinoma.
  * Lymphatic or vascular invasion (if this feature is unjudgeable due to piecemeal resection, no exclusion is done).
  * Tumor budding grade II-III.
* Suspicion of dissemination on investigations as mentioned in the inclusion criteria.
* Patients already receiving anti-tumor treatment for another tumor or a synchronic colorectal cancer.
* Patients in whom a second-look endoscopy would require major and unacceptable effort and / or resources, for instance clinical admission for bowel preparation, long travel, general anesthesia, extremely difficult to reach polypectomy site. Such at the decision of the patient and / or treating physician.
* Patient is planned for trans-anal surgery.
* Patient is not planned for surgery.
* Patient is pregnant.
* Patient does not provide written informed consent or is unable to provide such.