Evaluation of prognosis of rectal cancer patients with neoadjuvant chemoradiotherapy by clinical TNM stage: Is it suitable?

Abstract

e16029 Background: In the Union for International Cancer Control /American Joint Committee on Cancer TNM classification system, the prognosis of rectal cancer patients with adjuvant treatment are based on pre-radiotherapy clinical TNM stage. However, the value of this classification system is still debated. Here, we find that neoadjuvant pathologic TNM stage may be better than clinical TNM stage in patients with rectal cancer. Furthermore, we propose a novel risk stratification which may be more accurate in the assessment of prognosis of these patients. Methods: Between 2010 and 2015, 316 patients with rectal cancer who underwent neoadjuvant chemoradiotherapy followed by radical surgery were included for analysis. The clinicopathological factors for developing recurrences that affected prognosis were analyzed. Results: Our findings showed that the pathological complete response group had significantly better overall survival and recurrence-free survival than did the non-pCR group. Clinical N stage was not only an independent factor for developing recurrences but was also a significant prognostic factor in the pCR group, just as neoadjuvant pathologic TNM stage in the non-pCR group. Based on the independent prognostic factors, pCR patients were stratified into two recurrence risk categories: pCR with cN0 stage or pCR with cN+ stage. Non-pCR patients were stratified into three recurrence risk categories: non-pCR with ypTNM I stage, ypTNM II stage or ypTNM III stage, which might offer greater potential for the prognosis of patients with rectal cancer. Conclusions: Neoadjuvant pathologic TNM stage, rather than pre-radiotherapy clinical TNM stage, was an independent factor for developing recurrences in the non-pCR group. Furthermore, a novel risk stratification, which may be more accurate in the assessment of prognosis of rectal cancer patients, was proposed.