Management and Outcomes in Anal Canal Adenocarcinomas-A Systematic Review

(1) Background: Anal canal adenocarcinomas constitute 1% of all gastrointestinal tract cancers. There is a current lack of consensus and NICE guidelines in the United Kingdom regarding the management of this disease. The overall objective was to perform a systematic review on the multitude of practice and subsequent outcomes in this group. (2) Methods: The MEDLINE, EMBASE, EMCARE and CINAHL databases were interrogated between 2011 to 2021. PRISMA guidelines were used to select relevant studies. The primary outcome measure was 5-year overall survival (OS). Secondary outcome measures included both local recurrences (LR) and distant metastases (DM). The Newcastle-Ottawa Scale (NOS) was used to assess the quality of studies retrieved. The study was registered on PROSPERO (338286). (3) Results: Fifteen studies were included. Overall, there were 11,967 participants who were demographically matched. There were 2090 subjects in the largest study and five subjects in the smallest study. Treatment modalities varied from neoadjuvant chemoradiotherapy (CRT), CRT and surgery (CRT + S), surgery then CRT (S + CRT) and surgery only (S). Five-year OS ranged from 30.2% to 91% across the literature. LR rates ranged from 22% to 29%; DM ranged from 6% to 60%. Study heterogeneity precluded meta-analysis. (4) Conclusions: Trimodality treatment with neoadjuvant chemoradiotherapy (CRT) followed by radical surgery of abdominoperineal excision of rectum (APER) appeared to be the most effective approach, giving the best survival outcomes according to the current data.