S-1 monotherapy for previously treated non-small cell lung cancer: A retrospective analysis by age and histopathological type.

S-1, an oral fluoropyrimidine derivative, has been approved for the treatment of non-small cell lung cancer (NSCLC) in Japan. In the present study, the efficacy and safety of S-1 monotherapy for elderly patients with previously treated NSCLC were retrospectively evaluated, and the efficacy of S-1 monotherapy was compared by histopathological type. This retrospective study included 54 patients with advanced or recurrent NSCLC who had received S-1 monotherapy following the failure of previous chemotherapy regimens at our institutes. Patient outcomes were compared based on their age and histopathological type. S-1 was administered orally, twice daily, while the duration and interval were modified according to the medical condition of each patient. The default delivery schedule, the mean number of S-1 cycles, did not differ significantly between the two age groups (<70 and ≥70 years). The rate of therapy discontinuation, schedule modification or dose reduction due to intolerable toxicities or patient refusal was relatively frequent in the older group (40.7 and 55.6% for ages <70 and ≥70 years, respectively; p=0.414), and the incidence of grade 3 anemia was relatively high in the older group (3.7 and 18.5%, respectively; p=0.192). The response rates (13.0 and 4.8%, respectively; p=0.609) and disease control rates (39.1 and 33.3%, respectively; p=0.761) did not differ significantly between the two age groups. According to histopathological type, the disease control rate was significantly higher in adenocarcinoma (57.9%) compared to non-adenocarcinoma (20.0%, p=0.013). Thus, S-1 monotherapy may be equally effective and tolerated in patients <70 years and those ≥70 years. Additionally, adenocarcinoma may have a higher disease control rate than non-adenocarcinoma.