[Squamous cell carcinoma of the anal canal showing complete response following chemoradiotherapy--a case report].

We report a case of squamous cell carcinoma of the anal canal which showed complete response following chemoradiotherapy. A 54-year-old woman was diagnosed as having squamous cell carcinoma of the anal canal (T2N0M0 stage II). Chemoradiotherapy comprising peroral tegafur/uracil and external radiotherapy (60 Gy) to the pelvic space resulted in complete response 4 months after the initiation of the treatment. PET-CT showed recurrence in paraortic lymph node, right sacral and left pubic bone 11 months after the initiation of treatment, although the primary lesion did not relapse. The patient is now given 5-fluorouracil/cisplatin in addition to external radiotherapy (57.5 Gy) to the metastatic lymph node. This case suggests that we should take measures to prevent distant metastases in the treatment of squamous cell carcinoma of the anal canal.