A retrospective analysis of the efficacy and safety of capecitabine plus oxaliplatin (CapeOX) and docetaxel plus S-1 (DS) as adjuvant chemotherapy for pathological stage III (p stage III) gastric cancer (GC).

Abstract

342 Background: Adjuvant chemotherapy following surgical resection is the standard treatment for patients with p stage III GC in Japan. Although CapeOX and DS are available for adjuvant chemotherapy for stage III GC, there is limited data on which treatment is more effective. We aim to compare the efficacy and safety of CapeOX and DS as adjuvant chemotherapy in patients with p stage III GC. Methods: We extracted data of patients with p stage III GC who received either CapeOX (capecitabine on days 1–14 plus oxaliplatin on day1 for 8 cycles [q 3week]) or DS (S-1 on days 1–14 at 1st cycle [q 3 week], docetaxel on day 1 plus S-1 on days 1–14 during 2–7 cycles [q 3 week], and S-1 on days 1–28 up to 1 year [q 6 week]) as adjuvant chemotherapy after surgical resection at our institution from February 2016 to May 2022. Three-year relapse-free survival (RFS) and adverse events (AEs) were assessed. Cox proportional hazard model was used in multivariable analysis to assess the effect of independent variables on RFS. Results: A total of 74 patients were included in this study (CapeOX 31/ DS 43). Patient characteristics (CapeOX/DS) were as follows: median age, 60/64 years; male, 77/65 %; ECOG-PS 0/1, 45%/44%, 55%/56 %; p stage IIIA/IIIB/IIIC, 10%/30%, 48%/51 %, 42%/19 %. The 3-year RFS was 37% in the (hazard ratio [HR] = 0.81, P=0.48). For p stage IIIA, IIIB, and IIIC, the 3-year RFS in the CapeOX group and the DS group was 67% vs. 75% (HR = 0.56, P =0.52), 43% vs. 42% (HR = 1.11, P =0.81), and 23% vs. 0% (HR = 1.59, P =0.39), respectively. Multivariable analysis adjusted for p stage showed no significant differences in RFS between the CapeOX group and the DS group (HR=1.06, P=0.85). Compared to DS, CapeOX was associated with lower incidences of febrile neutropenia (0% vs 7%) and alopecia (6% vs 74%), and a higher incidence of peripheral neuropathy (80% vs 23%). Conclusions: This analysis indicates that CapeOX and DS have comparable efficacy as adjuvant chemotherapy for p stage III GC in terms of RFS, albeit with different profiles of AEs.