Long-term outcome of neoadjuvant chemoradiotherapy based on the depth of invasion in mrT3 low rectal cancer

noses of the two groups and their subgroups were compared. Results: The CRT and nCRT groups revealed no significant differences in the 3-year disease-free survival rate and the local recurrence rate for all the mrT3 patients (78.2% vs. 71.9%, P=0.608; 4.4% vs. 8.5%, P= 0.120) and mrT3a patients (82.4% vs. 81.8%, P=0.837; 5.8% vs. 5.9%, P=0.658). On the contrary, for the mrT3b patients, the CRT and nCRT groups revealed significant differences in the 3-year disease-free survival rate (84.4% vs. 42.4%, P=0.032) and local recurrence rate (0.0% vs. 18.2%, P=0.014). For the mrT3b,c patients, the CRT and nCRT groups revealed no significant difference in the 3-year disease-free survival rate (72.8% vs. 42.4%, P=0.060) but revealed a significant difference in the local recurrence rate (2.4% vs. 18.2 %, P= 0.021). COX regression analysis was utilized for 3-year disease-free survival, DMI and circumferential resection margin (CRM) were significant in the univariate analysis. Additionally, the multivariate analysis indicated that CRM is an independent impact factor (OR= 2.249, CI 1.067-4.742, P=0.033). Conclusion: CRT can improve the prognosis of patients with mrT3b,c low rectal cancer but may not significantly influence the prognosis of patients with mrT3a and CRM-negative low rectal cancer; surgical treatment can be performed