Safety and efficacy of S-1 monotherapy in elderly patients with advanced gastric cancer

Abstract

Although S-1 is effective against advanced gastric cancer (AGC), its efficacy in elderly patients has not yet been investigated sufficiently. We assessed the efficacy and safety of S-1 monotherapy in elderly patients with AGC. We conducted a retrospective review of the data of 153 patients with unresectable/recurrent gastric adenocarcinoma who received S-1 monotherapy as first-line chemotherapy at our institution. S-1 was administered orally twice daily at the dose of 40 mg/m², on days 1-28, every 6 weeks. We categorized the patients into three groups, the young (≤65 years old), the middle-aged (66-75 years old), and the elderly (≥76 years old); and the drug toxicity, objective responses, progression-free survivals, and overall survivals were compared among the three groups. The incidence of leukopenia of grade 3 or greater in the three groups was 7%, 5%, and 13%, and that of anemia was 9%, 18%, and 27%, respectively. In regard to nonhematological toxicities, the incidence of nausea of grade 3 or greater was 3%, 5%, and 13%; that of fatigue was 5%, 11%, and 20%; and that of anorexia was 5%, 6%, and 27%, respectively. As for the treatment efficacy, the objective response rates, median progressionfree survivals, and overall survivals in the young, middle-aged, and elderly groups were 53%, 46%, and 33%; 7.8, 5.6, and 3.9 months; and 16.9, 17.1; and 7.7 months, respectively. Although S-1 monotherapy showed moderate efficacy in elderly (≥76 years) patients with AGC, patients in this age group showed higher incidences of severe toxicities than the younger patients.