Oncologic colorectal resection after endoscopic treatment of malignant polyps: does endoscopy have an adverse effect on oncologic and surgical outcomes?

Background: Early colorectal cancer is increasingly treated by endoscopic removal. In cases of incomplete resection or high-risk carcinoma, additional surgery is necessary.

Objective: To evaluate the frequency of subsequent oncologic surgery after endoscopic resection of colorectal cancer, the rate of lymph node metastasis, residual cancer, and morbidity and mortality rates of the operation. Any eventual adverse effect of the prior endoscopic therapy on the surgical and oncologic outcome was assessed.

Design: Retrospective review of prospectively collected data.

Setting: University hospital.

Patients: Sixty-six consecutive patients with incomplete endoscopic treatment and need for additional surgery between 2004 and 2011.

Intervention: The data of these patients were compared with those of a group of patients with surgery for early colorectal cancer during the same period without prior endoscopic resection as the control group.

Main outcome measurements: Rate of lymph node metastasis and residual cancer, perioperative morbidity and mortality.

Results: The lymph node metastasis rate after oncologic resection was 8.6%, and the residual cancer rate was 41%. Risk factors for residual cancer were macroscopic incomplete resection (P < .0001), positive resection margins (P = .03), and piecemeal resection (P = .004). No mortality was observed. Perioperative morbidity, mortality, and oncologic outcome were not significantly different in the group with prior endoscopic resection compared with the primarily operated group.

Limitations: Retrospective study.

Conclusion: Endoscopic treatment of malignant polyps does not worsen surgical and oncologic outcomes in cases of subsequent surgery. Because mortality and morbidity are low, oncologic resection generally should be done in the presence of risk factors for residual cancer.