Duodenal ulcer induced by TS-1 in adjuvant chemotherapy for head and neck cancer: A case report

TS-1 is an oral anticancer agent which has significant therapeutic action against head and neck cancer. However, myelosuppression, liver and digestive tract disorders are known as adverse reactions. We present a case of duodenal ulcer which was considered to be induced by TS-1. A 76-year-old female, who was diagnosed as having lower gingival cancer, underwent left neck dissection, hemimandibular resection and reconstruction with rectal abdominal myocutaneous free flap. She was given a daily dose of 100 mg of TS-1 as adjuvant chemotherapy after the surgical treatment. She complained of dull abdominal pain 12 days after treatment with TS-1. Because the symptom became worse, she was hospitalized urgently. Endoscopic examination showed multiple duodenal ulcers which were well defined, with even deepness. We immediately stopped TS-1 administration. These ulcers subsided after the withdrawal of TS-1 with fasting and fluid therapy for several days. In case of long-term administration of TS-1 for advanced / recurrent head and neck cancer, it must be considered that acute ulcer of the digestive tract may be induced as an adverse reaction.