Rectal cancer patients after neoadjuvant radiotherapy (30Gy/10f) with negative lymph node may not benefit from postoperative adjuvant chemotherapy: a retrospective study.

OBJECTIVE: The purpose of this study is to evaluate whether adjuvant chemotherapy could bring oncologic benefit to all patients who underwent neoadjuvant radiotherapy (30Gy/10f). METHODS: Rectal cancer patients receiving preoperative radiotherapy between July 2002 and April 2009 were retrospectively identified. RESULTS: A total of 225 patients were enrolled in this study. One hundred thirty-one patients received postoperative adjuvant chemotherapy, and 94 patients did not. The 120 ypN+ and 105 ypN- patients were divided into chemo and non-chemo groups. Two groups of patients did not show any significant difference in terms of gender, age, ypT stage, preoperative serum carcinoembryonic antigen (CEA) level, differentiation, circumferential margin (CRM), lymphovascular invasion (LVI), surgical approach, local recurrence, and distant metastasis (P > 0.05). Survival analysis showed that in ypN+ patients, the 5-year overall survival (OS) rate and 5-year disease-free survival (DFS) rate in chemo group were both significantly higher than non-chemo group (P < 0.05). In ypN- patients, the 5-year OS rate and 5-year DFS rate did not show any significant difference in the two groups (P > 0.05). Subgroup analysis showed that the 5-year OS rate and 5-year DFS rate in ypT0-2 N- patients (P > 0.05) and ypT3-4 N- patients (P > 0.05) did not show any significant difference, either. CONCLUSIONS: Based on a Chinese protocol, patients with ypN- stage may not benefit from adjuvant chemotherapy, regardless of the ypT stage, while the ypN+ patients may benefit from adjuvant chemotherapy. More randomized clinical trials are needed in the future.