Radiotherapy May Offer a Recurrence and Survival Benefit in Rectal Cancers Treated Surgically with Transanal Endoscopic Microsurgery: A Systematic Review and Meta-analysis

Abstract

Several studies report outcomes of Transanal Endoscopic Microsurgery (TEMS) surgery in combination with radiotherapy, however the combination of those treatments is provided mostly on an adhoc individual basis and the role of radiotherapy remains unclear. The aim of this study was to identify the effect of neo-adjuvant or adjuvant radiotherapy in the oncological outcomes of rectal cancer treated surgically with TEMS. We performed a systematic review of the literature on MEDLINE and Pubmed databases. Data were extracted by two independent reviewers and meta-analyzed using an inverse variance heterogeneity model to calculate overall (pooled) effect sizes for survival or recurrence of disease against neo+/-adjuvant treatment. A total of 48 studies were included in the qualitative meta-analysis which included 3,285 patients with rectal cancer. The overall survival odds ratio (OR), was 9.39 (95% CI=6.1-14.4) with a Cochran's Q variable of 151.7 on 47 degrees of freedom (d.f.) (p=0.000). Recurrence-free OR was 8.7 (95%CI=6.58-11.44) with a Cochran's Q variable of Q=145.2 on 44 d.f. (p=0.000). Studies which contained more than 10% of pT3 tumours, and provided neo+/-adjuvant treatment in more than 35% of cases, were associated with survival benefit, as demonstrated by an overall odds of survival of 32.2 (95%CI=16.3-63.5, p=0.001, Q=8.4, p=0.21). Studies that contained more than 10% of pT3 tumours and provided neo+/-adjuvant treatment in more than 20% of the cases had an overall effect size of recurrence-free odds of 20.23 (95%CI=13.84-29.57, p=0.000, Q=2.18, p=0.54). There seems to be a benefit from radiotherapy on overall survival and recurrence-free odds, which is more apparent in cohorts with more than 10% of pT3 tumours. Our results suggest that neo-adjuvant or adjuvant radiotherapy should be considered for inclusion in formal treatment protocols for rectal cancers treated with TEMS as they offer a recurrence and survival benefit.