Long-Term Outcomes of S-1 and Oxaliplatin Neoadjuvant Chemotherapy with Total Mesorectal Excision and Lateral Lymph Node Dissection for Rectal Cancer

Purpose: Chemoradiotherapy (CRT) for rectal cancer is limited by its harmful side effects and its insufficient benefit on lateral lymph node metastases. The purpose of this study was to evaluate the long-term outcomes of S-1 and oxaliplatin with total mesorectal excision (TME) and lateral lymph node dissection (LLND) without radiation for rectal cancer. Methods. Fifty-two patients who underwent neoadjuvant chemotherapy (NAC) followed by TME and LLND in one of four study hospitals were evaluated. The primary endpoint was to determine the cumulative local recurrence rate and other long-term outcomes including the local recurrence rate, relapse-free survival, and overall survival. Expected post-NAC and surgical outcomes were prospectively analyzed. Results. The overall recurrence rate was 15.4%, with eight patients developing distant recurrences. The local recurrence rate was 7.7% (n = 4). Among the 4 patients with local recurrence, 3 (5.8%) patients had central pelvis recurrence, and 1 (1.9%) patient had lateral pelvis recurrence. The 3-year survival rate was 98.1%, and the 3-year relapse-free survival rate was 84.6%. The risk factors for local recurrence were mucinous carcinoma and ineligibility for R0 resection. Pathological mesorectal lymph node metastasis and local recurrence were independent risk factors of poor survival. Conclusions. Preoperative chemotherapy with TME and LLND is useful for avoiding radiation-related adverse events and improving prognosis in rectal cancer.