Risk and time pattern of recurrences after local endoscopic resection of T1 colorectal cancer: a meta-analysis.

Abstract BACKGROUND AND AIMS Growing numbers of T1 CRC patients are being treated with local endoscopic resection only and as a result, the need for optimization of surveillance strategies for these patients also increases. We aimed to estimate the cumulative incidence and time pattern of CRC recurrences for endoscopically treated T1 CRC patients. METHODS Using a systematic literature search in PubMed, EMBASE, Web of Science and Cochrane Library (from inception till 15 May 2020), we identified and extracted data from studies describing the cumulative incidence of local or distant CRC recurrence for T1 CRC patients treated with local endoscopic resection only. Pooled estimates were calculated using mixed-effect logistic regression models. RESULTS Seventy-one studies with 5167 unique, endoscopically treated T1 CRC patients were included. The pooled cumulative incidence of any CRC recurrence was 3.3% (209 events; 95%-CI 2.6%-4.3%; I2 = 54.9%), with local and distant recurrences being found at comparable rates (pooled incidences 1.9% and 1.6%, respectively). CRC-related mortality was observed in 42 out of 2519 patients (35 studies; pooled incidence 1.7%, 95%-CI 1.2%-2.2%; I2 = 0%), and the CRC-related mortality rate among patients with recurrence was 40.8% (42/103 patients). The vast majority of recurrences (95.6%) occurred within 72 months of follow-up. Pooled incidences of any CRC recurrence were 7.0% for high-risk T1 CRCs (28 studies; 95%-CI 4.9%-9.9%; I2 = 48.1%) and 0.7% (36 studies; 95%-CI 0.4%-1.2%; I2 = 0%) for low-risk T1 CRCs. CONCLUSIONS Our meta-analysis provides quantitative outcome measures which are relevant to guidelines on surveillance after local endoscopic resection of T1 CRC.