Colonic giant polyps (≥2 cm) are closely associated with malignancy and can develop into invasive carcinoma; therefore, current guidelines recommend that colonic giant polyps can be resected endoscopically. However, due to their large size, shape, and special location, endoscopic resection is difficult and failure to completely remove them may increase the risk of postoperative recurrence.
Prof. Hassan et al. from the Endoscopy Unit of the Margherita Hospital in Novo Regina, Italy, conducted a study suggesting that endoscopic resection of colonic giant polyps is safe and effective, and the article was recently published in the journal Gut.
The meta-analysis collected studies on endoscopic resection of large colon polyps from MEDLINE, EMBASE, and the Cochrane Central Register between 1966-2014, which also included studies of endoscopic resection of ≥20 mm colon tumors.
Studies primarily assessed the rate of surgical resection due to endoscopic nonradical resection procedures or adverse events, as well as the rate of complete endoscopic resection, the incidence of invasive cancer, adverse events, recurrence, and death. Study quality was determined based on the Newcastle-Ottawa score.
A total of 50 studies with 6,442 patients totaling 6,779 colonic giant polyps were included in the study. The results showed that 503 (8%) of the 6442 patients underwent reoperation for incomplete endoscopic resection, with a large heterogeneity between studies. Only 31 (1%) patients underwent reoperation for adverse events, with less heterogeneity between studies, indicating a low incidence of adverse endoscopic resection events.
Among patients who underwent the procedure again, the rates of invasive carcinoma, nontherapeutic endoscopic resection, contemporaneous injury, and recurrence were 58%, 28%, 2.2%, and 5.9%, respectively. Meanwhile, endoscopic resection complications were low, with an incidence of endoscopic perforation of only 1.5% (96/6595) and bleeding of 6.5% (423/6474).
Endoscopic review was performed in 5836 patients in all studies, but 502 (8.6%) patients were lost to follow-up. A total of 5334 patients completed follow-up, of which 735 (13.8%) patients had recurrence detected endoscopically and were surgically resected again by endoscopy with a success rate of 90.3% (664/735); 14 (0.3%) patients progressed to invasive carcinoma. The final mortality rate associated with colonic giant polyps was only 0.08% (5/6278).
These results showed that in a systematic evaluation of 6442 patients, the efficiency of endoscopic resection of large colon polyps was 92%, with an adverse event rate of only 1%, indicating that the technique is safe and reliable.
Although the recurrence rate after endoscopic resection was nearly 14%, the majority of patients had a good prognosis with repeat endoscopic treatment. The advent of endoscopic submucosal dissection (EMR, ESD) has substantially reduced the risk of recurrence, but it is not applicable to invasive cancer.
As analyzed by the authors, the most important reason for the failure of endoscopic resection is the close relationship between colonic giant polyps and malignancy, which can progress to invasive carcinoma.
From this study, endoscopic resection of colonic giant polyps is safe and effective; however, optimization and standardization of endoscopic resection techniques are needed, and regular endoscopic review is necessary to maintain its long-term efficacy.