[A case of advanced lateral wall oropharyngeal carcinoma showing complete response to chemotherapy with TS-1].

We report a recent case of squamous cell carcinoma originating in the right tonsil, with metastasis to the right superior cervical lymph nodes (T3N2bM0: stage IVA). Chemo-radiotherapy was administered as first-line therapy; and adjuvant chemotherapy with TS-1 was applied during the subsequent 4-week period for the treatment of the residual tumor in the neck. In this patient (female, 61 years old), the primary tonsillar tumor showed a complete response to the first-line therapy, however, the metastatic lesions in the cervical lymph nodes persisted, although the nodes also decreased markedly in size. Subsequent chemotherapy with TS-1 (80 mg/day) given for a 4-week period resulted in complete disappearance of the residual malignancy (CR), as determined by palpation and diagnostic imaging. No serious adverse events occurred during the therapy. Surgical treatment in patients with advanced head and neck cancer often results in a diminished quality of life. Although further accumulation of cases is necessary, TS-1, which allows oral chemotherapy on an outpatient basis, would seem to be a useful drug for adjuvant chemotherapy following radical irradiation in patients with advanced head and neck cancer.