Real-world Outcomes of Adjuvant Gemcitabine Versus Gemcitabine Plus Capecitabine for Resected Pancreatic Ductal Adenocarcinoma

Background: Adjuvant chemotherapy is the standard treatment after curative-intent surgery for pancreatic ductal adenocarcinoma (PDAC). The phase-3 ESPAC-4 trial demonstrated significantly improved overall survival (OS) with Gemcitabine plus capecitabine (GemCap) over Gemcitabine (Gem) in Europe. We conducted a retrospective efficacy and safety evaluation of GemCap versus Gem in an Asian population. Methods: This retrospective analysis included 292 patients with PDAC who received adjuvant Gem or GemCap after curative resection between January 2017 and December 2020 at Asan Medical Center, Seoul, Korea. Results: Adjuvant Gem and GemCap were administered to 161 (55.1%) and 131 (44.8%) patients, respectively. The Gem group had significantly older patients (median 66 versus 63 years, p = 0.001); otherwise, the groups had similar baseline characteristics. With median follow-up durations of 39.4 [95% confidence interval (CI), 36.9–45.0] and 39.4 (95% CI, 34.7–41.6) months in the Gem and GemCap groups, the median OS was 36.8 (95% CI, 29.7–43.5) and 46.1 (95% CI, 31.5–not reached) months in the Gem and GemCap groups, respectively [unadjusted hazard ratio (HR) = 0.7; 95% CI, 0.5–1.0; p = 0.07). The median recurrence-free survival was 14.3 (95% CI, 12.9–17.7) and 17.0 (95% CI, 13.3–28.2) months, respectively ( p = 0.5). Hand-foot skin reactions (any grade, 15.3% versus 0.6%; p < 0.001), neutropenia (78.6% versus 67.7%, p = 0.04) and thrombocytopenia (30.5% versus 20.5%, p = 0.04) were more common in the GemCap group. Multivariate analysis revealed adjuvant GemCap – compared with Gem – to be significantly associated with better OS (adjusted HR = 0.6; 95% CI, 0.4–0.9; p = 0.01). Otherwise, moderate or poor histological grade, lymph node positivity, positive resection margin, and elevated CA 19-9 (>median) were significantly associated with worse OS. Conclusions: Adjuvant GemCap showed the consistent clinical outcomes with the ESPAC-4 trial. As mFOLFIRINOX is the new standard treatment for medically fit patients with resected PDAC, further evaluation of optimal adjuvant chemotherapy in daily practice is warranted.