Long‐term outcomes of neoadjuvant gemcitabine, nab‐paclitaxel, and S1 (GAS) in borderline resectable pancreatic cancer with arterial contact: Results from a phase II trial

Abstract Background/Purpose This study reports the long‐term results of a phase II trial evaluating the clinical efficacy of neoadjuvant gemcitabine, nab‐paclitaxel, and S1 (GAS) in borderline resectable pancreatic cancer with arterial contact (BRPC‐A). Methods A multicenter, single‐arm, phase II trial was conducted. Patients received six cycles of GAS and patients without progressive disease were intended for R0 resection. Results Of the 47 patients, 45 (96%) underwent pancreatectomy. At the time of this analysis, all patients were updated with no loss to follow‐up. A total of 30 patients died, while the remaining 17 patients were followed for a median of 68.1 months. The updated median overall survival (OS) was 41.0 months, with 2‐ and 5‐year OS rates of 68.0% and 44.6%, respectively. Multivariate analysis in the preoperative model showed that a tumor diameter reduction rate ≥10% and a CA19‐9 reduction rate ≥95% after neoadjuvant chemotherapy remained independently associated with favorable survival. In the postoperative multivariate model, no lymph node metastasis, no major surgical complications, and completion of adjuvant chemotherapy were independently associated with improved OS. Conclusions This long‐term evaluation of the neoadjuvant GAS trial demonstrated the high efficacy of the regimen, suggesting that it is a promising treatment option for patients with BRPC‐A.