Factors Influencing Clinicians' Choice of Adjuvant S-1 versus Capecitabine plus Oxaliplatin after Curative Gastrectomy in Patients with Gastric Cancer

Purpose: Two recent randomized, phase III trials in Asia (ACTS-GC and CLASSIC) documented the survival benefit of postoperative chemotherapy after D2 lymph node dissection in patients with gastric cancer. We sought to determine what factors influenced clinicians' choices of either S-1 or capecitabine plus oxaliplatin (CAPOX) as adjuvant therapy after curative D2 gastrectomy. Materials and Methods: We retrospectively reviewed the clinicopathologic factors and adjuvant treatments for 435 patients from nine centers in Korea who were treated with either S-1 or CAPOX adjuvant chemotherapy after undergoing curative D2 gastrectomy between January 2013 and July 2014. Results: Of the 435 patients, 204 (46.9%) were treated with S-1 and 231 (53.1%) were treated with CAPOX. The median age at diagnosis was 61 years (range, 30-88). CAPOX was prescribed more often for patients who were 65 years of age or younger than for patients who were age 65 or older (77.1% vs. 22.9%, P<0.0001). Of the patients in stage II, 121 (60.8%) were treated with S-1 and 78 (39.2%) were given CAPOX; however, of those in stage III, 83 (35.2%) received S-1 and 153 (64.8%) were treated with CAPOX (P<0.0001). Conclusions: Clinicians only preferred CAPOX for younger patients with stage III gastric cancer after curative D2 gastrectomy. However, for elderly patients, clinicians more chose S-1 regardless of the stage.