Complete Response of Para-Aortic and Lateral Pelvic Lymph Node Recurrence of Rectal Cancer Treated to S-1 Monotherapy

This report presents a case of para-aortic and lateral pelvic lymph node recurrence of rectal cancer that showed complete response to S-1 monotherapy. A 69-year-old man underwent low anterior resection for rectal cancer in 2007. Para-aortic lymph and right lateral pelvic lymph node recurrence occurred in 2008. He received a fluorouracil/folinic acid plus oxaliplatin regimen; however, G4 neutropenia and G3 fatigue were experienced. We started S-1 monotherapy as a salvage treatment. Abdominal computed tomography did not reveal any para-aortic and lateral pelvic lymph nodes recurrence after 10 cycles of S-1 monotherapy. Hence, response in this case was classified as a complete response. No recurrence was noted 36 months after the complete response. S-1 monotherapy is likely to be effective in treating patients with metastatic colorectal cancer who do not respond to standard combination chemotherapy.