Octreotide acetate enables the administration of chemoradiotherapy, including the oral anticancer drug S-1, in gastric cancer patients with malignant gastrointestinal obstruction.

Advanced gastric cancer frequently results in the inability to ingest food or drink orally, a condition called malignant gastrointestinal obstruction (MGO). MGO is clinically defined as a gastrointestinal outlet obstruction caused by a large tumor, or malignant bowel obstruction with peritoneal dissemination. MGO impacts the quality of life by interfering with oral intake and by causing gastrointestinal symptoms, such as nausea, vomiting and abdominal pain. Octreotide acetate (OA) is an analogue of somatostatin which has been increasingly used to relieve gastrointestinal symptoms since it decreases the secretion of digestive juices and increases the absorption of water and electrolytes. In Japan, the oral anticancer drug S-1 was recently adopted as a key chemotherapeutic agent in advanced gastric cancer; however, its oral formulation precludes its utility in the MGO setting. This is a pilot study of chemoradiotherapy plus OA in gastric cancer with MGO. Patients were initially treated with OA to control gastrointestinal symptoms. Following resolution of their symptoms, the patients received chemotherapy with S-1 plus low-dose cisplatin and radiation. Irradiation was targeted at the primary tumor and surrounding lesions, including the lymph nodes. Grade 4 toxicity was observed in only 1 patient, and no treatment-related deaths were noted. After treatment, 3 patients achieved a partial response and 4 achieved stable disease. Of the 9 patients, 8 were able to tolerate solid food orally and were discharged. The outcomes of these cases suggest that OA is a useful adjunctive therapy that enables advanced gastric cancer patients with MGO to receive S-1-containing chemotherapy.