Clinical experience with chemoradiotherapy comprising S-1 plus low-dose cisplatin in a patient with stage IV anal cancer

We report a case of anal cancer in a 58-year-old woman who complained of narrow, bloody stools and anal pain. Physical examination revealed anal stenosis associated with a circular mass arising in the anal canal. Histological examination of biopsy specimens confirmed a diagnosis of moderately differentiated squamous cell carcinoma. Enhanced computed tomography revealed anal cancer invading the levator ani and the vagina, with lymph-node, multiple hepatic, and pulmonary metastases. The patient received two cycle of chemoradiotherapy with S-1 plus low-dose cisplatin with rest for 4 weeks, leading to complete response of the primary lesion and a partial response of the metastatic lesions. Each cycle included oral S-1 (120 mg/body; day 1-21), cisplatin (10 mg/body; day 1-5, 8-12) and radiotherapy (2 Gy/day; day 1-5, 8-12, 15-19). Adverse effects of treatment were mild perineal skin erosion and mild appetite loss, but no hematologic toxicity. Although the patient died 16 months after first admission, chemoradiotherapy with S-1 plus cisplatin is potentially effective for the management of advanced anal cancer.