[Long-term conditional disease-free survival for rectal cancer patients underwent neoadjuvant chemoradiotherapy]

Objective: To explore the application value of the conditional disease-free survival (cDFS) analysis in predicting prognosis of stage-specific rectal cancer patients underwent neoadjuvant chemoradiotherapy (nCRT). Methods: Clinicopathologic data of 436 patients with rectal cancer received nCRT and radical operation in Cancer Hospital, Chinese Academy of Medical Sciences between January 2004 and December 2016 were retrospectively reviewed. With reference to conditional probability, the 3-year cDFS of patients at different ypTNM stage after completion of nCRT was estimated using the Kaplan-Meier method. Results: There were 66 patients of ypTNM stage 0 (pathological complete response), 87 patients of ypTNM stage Ⅰ, 135 patients of ypTNM stage Ⅱ and 148 patients of ypTNM stage Ⅲ. The 3-year accumulated DFS of patients with ypTNM stage 0, ypTNM stage Ⅰ, ypTNM stage Ⅱ, and ypTNM stage Ⅲ were 97.0%, 93.1%, 85.2%, and 64.2%, respectively. On the condition of postoperactive disease-free survival for 1 year, 2 years, 3 years, 4 years, and 5 years, the corresponding 3-year cDFS of patients at ypTNM stage 0 were 97.0%, 95.5%, 96.9%, 98.4%, 100.0%, respectively. The corresponding 3-year cDFS of patients at ypTNM Ⅲ were 68.2%, 79.3%, 86.3%, 92.1%, 96.4%, respectively. The more advanced ypTNM staging resulted in the more improvement of 3-year cDFS being acquired. Conclusion: cDFS is a better method to reflect the dynamic changes of the prognosis of rectal cancer patients with nCRT in different ypTNM stage, and it is useful to guide the clinicians to assess the prognosis and propose appropriate surveillance.