Which is the better prognostic factor in rectal cancer patients who received neoadjuvant chemoradiotherapy: cTNM stage vs. ypTNM stage?
693 Background: Neoadjuvant chemoradiotherapy (nCRT) in rectal cancer is widely applied in patients with cTNM II and III stage. However, it is still obscure which staging system, either clinical (c) or pathologic (yp), influences in prognosis. This study aims to evaluate the current staging system predicting prognosis in the locally advanced rectal cancer patients. Methods: Among 221 patients who were diagnosed with rectal cancer and underwent curative resection from January 2009 to February 2013, 141 patients who received nCRT were included. The ypTNM stage was categorized: complete remission and stage I to ypI. Results: Mean follow-up period was 36.3 ± 15.1 months. Disease-free survival (DFS) was not associated with age, sex, Anesthesiologists classification, types of operative procedure, tumor cell differentiation, tumor location, tumor infiltration, preoperative CEA level, adjuvant chemotherapy. cTNM stage did not demonstrate any correlation with DFS (cII % vs cIII %, P = 0.266). However, DFS did exhibit statistically significant association with postoperative CEA level (P < 0.001) and ypTNM stage. 3-year DFS rate for each categorized stage is as followed – ypI, 87.9%; ypII, 67.8%; ypIII, 53.3% (ypI vs. ypII P = 0.009, ypI vs. ypIII P < 0.001, ypII vs. ypIII P= 0.185). Conclusions: Oncologic outcome of the patients with locally advanced rectal cancer is associated with pathologic TNM stage. Based on our results, we think that adjuvant chemotherapy given to patients with complete remission or pathologic stage I may be reconsidered.