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

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. 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. 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). 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.