Recurrence and cancer-specific mortality after endoscopic resection of low- and high-risk pT1 colorectal cancers. a meta-analysis

Background and Aims: Clinical management after complete endoscopic resection of pT1 colorectal cancers (CRCs) is still under debate. Follow-up data are heterogeneous and poorly reported, resulting in variable clinical management. Our aim was to meta-analyze recurrence and cancer-specific mortality (CSM) occurring after endoscopic resection of low- and high-risk pT1 CRCs undergoing conservative (nonsurgical) management. Methods: Literature was systematically searched until February 2019 for studies describing patients with pT1 CRCs, histologically classifiable as low or high risk, endoscopically resected without complementary surgery and with ≥12 months of follow-up. Pooled cumulative incidence (and incidence rate when specific follow-up intervals were available) of recurrence and CSM were calculated separately for low- and high-risk pT1 CRCs. Quality, publication bias, and heterogeneity were explored. Results: Pooled cumulative incidences of recurrence and CSM among high-risk lesions (5 studies, 571 patients) were, respectively, 9.5% (95% confidence interval [CI], 6.7%-13.3%; I2 = 38.4%) and 3.8% (95% CI, 2.4%-5.8%; I2 = 0%), whereas among low-risk lesions (7 studies, 650 patients) they were, respectively, 1.2% (95% CI, .6%-2.5%; I2 = 0%) and .6% (95% CI, .2%-1.7%; I2 = 0%). Pooled incidence rates of recurrence and CSM among high-risk lesions (3 cohorts, 237 patients) were, respectively, 11 (95% CI, 2-20; I2 = 43.3%) and 4 (95% CI, 1-7; I2 = 0%) per 1000 patient-years, whereas among low-risk lesions (3 cohorts, 229 patients) they were 3 (95% CI, 0-6; I2 = 0%) and 2 (95% CI, 0-4; I2 = 0%) per 1000 patient-years, respectively. No publication bias or significant heterogeneity was found. Conclusions: Pooled estimates of adverse events after endoscopic resection of pT1 CRCs suggest a conservative approach for low-risk lesions. In high-risk lesions, increased surgical risk might justify a conservative management, whereas fitness for surgery makes surgical completion appropriate.