Letter to the editor: 5-year follow-up results of a JCOG1104 (OPAS-1) phase III non-inferiority trial to compare 4 courses and 8 courses of S-1 adjuvant chemotherapy for pathological stage II gastric cancer
1 Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-Gil, Songpa-gu, Seoul, 05505, Republic of Korea.
2 Department of Clinical Epidemiology and Biostatistics, University of Ulsan College of Medicine, Seoul, South Korea.
3 Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-Gil, Songpa-gu, Seoul, 05505, Republic of Korea. ykkang@amc.seoul.kr.