A Case Report of a Pathological Complete Response of Rectal Cancer to Preoperative Chemoradiotherapy with Tegafur]

We report the case of a patient with advanced rectalcancer who achieved a pathologicalcompl ete response to preoperative chemoradiotherapy(CRT). A 65-year-old man was diagnosed as having a two-thirds circumferentialwel l- to moderately differentiated tumor(Rb-P, type 2). To controll ocalrecurrence, we treated the patient with CRT. Radiotherapy was adminis- tered in fractions of 2 Gy/day(total, 40 Gy). Concurrently, S-1was administered orally at a fixed daily dose of 80mg/m2 for 20 days. Withdrawaland /or dose reduction of S-1 was not necessary in spite of Grade 1 or 2 toxic effects, including diarrhea and periproctitis, occurring on day 7. Laparoscopic abdominoperinealresection was performed 6 weeks after the finaldose of chemotherapy was administered. The histopathological regression grade was Grade 3. No recurrence was detected on enhanced CT more than 5 years after surgery. This case suggests that the regimen was both effective and tolerated, and that preoperative chemoradiotherapy may be effective for tumor suppression to prevent local recurrence.