Oncological Outcomes of Transanal Endoscopic Microsurgery Plus Adjuvant Chemoradiotherapy for Patients with High-Risk T1 and T2 Rectal Cancer.

Background: Radical surgery is recommended for high-risk pathological stage T1 (pT1) or pT2 rectal cancer after transanal endoscopic microsurgery (TEM). However, in clinical practice, many patients may unfit or decline radical surgery. In recent years, adjuvant chemoradiotherapy (CRT) after TEM was considered as an alternative to radical surgery for these patients. This study aimed to assess oncological outcomes of adjuvant CRT after TEM for high-risk early rectal cancer. Materials and Methods: We collected retrospectively data of 97 patients who underwent TEM with pT1 and pT2 between January 2008 and December 2018. Of these, 35 patients were excluded. Of the remaining 62 patients, 42 were managed by TEM alone and 20 by TEM plus adjuvant CRT. Demographics, recurrence, and survival were analyzed between the two groups. Results: At a median follow-up of 52.5 months, the 3-year local recurrence-free survival and disease-free survival (DFS) in TEM alone group were significantly lower than those in TEM+CRT group (66.6% versus 93.3%, P  = .035; 63.7% versus 93.3%, P  = .022). Although the 3-year overall survival in TEM+CRT group was higher than TEM alone group (100% versus 83.3%), the difference was not statistically significant ( P  = .13). The local recurrence rate in TEM alone was 31%, compared with 5% in TEM+CRT group ( P  = .025). Multivariate analysis showed that adjuvant CRT was an independent prognostic factor for DFS (hazard ratio: 0.094; 95% confidence interval: 0.001-0.764; P  = .027). Conclusions: Our study suggests that adjuvant CRT after TEM may be an alternative for pT1 high-risk and T2 rectal cancer who are not suitable or unwilling to undergo salvage radical surgery.