Total Neoadjuvant Therapy for Rectal Cancer: the Case Report

Abstract

We report a case of advanced rectal cancer that could be radically resected after total neoadjuvant therapy (TNT). A 65-year-old man underwent TNT for lower rectal cancer. The patient received a short course of chemoradiation therapy (CRT) at a total dose of 30 Gy to the pelvic area, including lateral lymph nodes, in fractions of 3 Gy administered five times a week over 10 days (days 1-5 and 8-12). The CRT was given in combination with S-1 at a dose of 80 mg twice daily on all days of radiotherapy. After CRT, the patient was scheduled to receive two cycles of S-1 + oxaliplatin (SOX) therapy. SOX was administered over 3 weeks (130 mg/m² oxaliplatin on days 20 and 41, and 80 mg oral S-1 on days 20-33 and 41-54). Robotically-assisted laparoscopic low anterior resection was performed on day 77. Histopathological findings showed only a small amount of residual tumor (residual tumor volume of less than 5%), and the radial margin was negative. There were no severe adverse events, postoperative complications, or functional disorders. These findings demonstrated the effectiveness and safety of TNT with short-term irradiation for rectal cancer. This regimen may be a new candidate for neoadjuvant treatment of previously untreated rectal cancer.