Synchronous polypectomy during endoscopic diagnosis of colorectal cancer - is the risk of tumour implantation at the polypectomy site significant?

BACKGROUND

Synchronous polypectomy in colonic malignancies is contentious due to the perceived risks of tumour implantation at polypectomy sites (PS). We assess the risks of tumour implantation after synchronous polypectomy.

METHODS

An analysis of all endoscopies for cancer that were accompanied by synchronous polypectomies from 2005 to 2009 was performed. The incidence of metachronous colorectal cancers located at the same segment of a previous PS was the surrogate for tumour implantation. Data on patient demographics, tumour and polyp location(s) and follow-up outcomes were extracted. The rate of metachronous lesions at the same segment of a previous PS between patients who had all synchronous PS resected (Group A) and patients with PS left in-situ (Group B) were compared.

RESULTS

Two hundred and eighty-four patients had synchronous polypectomy performed during their initial endoscopy for cancer. Three patients were lost to follow-up and, in the remaining 281 patients, 87 (31.0%) were in Group A while 194 (69%) were in Group B. Median age, gender, tumour location, tumour stage, and pathological characteristics were similar between both groups. 2 (0.7%) patients developed local recurrences. Six (2.1%) patients developed metachronous lesions, four of which were located at the same segment where synchronous polypectomy was previously performed. The rates of metachronous lesions at the PS in groups A and B were similar at 1.1% (1/87) and 1.5% (3/194), respectively (p = 0.795).

CONCLUSION

Malignant implantation after synchronous polypectomy in the setting of a newly diagnosed cancer remains unproven. Even if tumor implantation did occur, the incidence is likely low.