Is it safe to omit neoadjuvant chemo-radiation in mucinous rectal carcinoma?

Abstract Background Purpose was to compare the oncologic outcome of neoadjuvant chemoradiotherapy (nCXRT) versus postoperative chemoradiotherapy (pCXRT) for locally advanced mucinous rectal carcinoma (MRC) having curative total mesorectal excision (TME). Methods One hundred and two patients with MRC (T3-4 and/or N1-2) of middle and lower third rectum were included. Patients were non-randomly divided into 2 groups: Group A (N = 61) had nCXRT followed by total mesorectal excision (TME) after 8–11 weeks and Group B (N = 41) had TME followed by pCXRT. Primary end points were disease free survival (DFS) and overall survival (OS). Secondary endpoints were tumor regression grade (TRG) and morbidity. Results In group A, 29 patients had partial response after nCXRT, 26 patients showed no change and 6 patients had progression. TME was done in 55 patients in group A and 41 patients in group B. Six patients in group A turned to be unresectable after nCXRT due to progressive disease. Mean follow-up was 53 months. In patients received TME, Four-year DFS was higher in group A compared to group B yet not statistically significant (DFS 0.69 [95% CI 0.54–0.85] vs. 0.67 [95% CI 0.47–0.87]; P = 0.39). However, actuarial 4 years OS was comparable in both groups (0.72 [95% CI 0.59–0.91] vs. 0.70 [95% CI 0.55–0.88]; P = 0.46 in groups A and B respectively). Multivariate analysis revealed that age