First line gemcitabine and nab-paclitaxel chemotherapy for localized pancreatic ductal adenocarcinoma.

Abstract

369 Background: Chemotherapy is widely used as a component of treatment of localized pancreatic ductal adenocarcinoma (PDAC). Pre-operative chemotherapy is associated with early treatment of micro-metastases and guaranteed delivery of all components of multimodality therapy. For locally advanced (LA) PDAC, induction chemotherapy is standard of care. We evaluated the use of gemcitabine and nab-paclitaxel (Gem/nab-P) as first-line therapy in localized PDAC. Methods: Records of pts with localized PDAC who initiated Gem/nab-P at a single institution from 2013-2015 were retrospectively reviewed. Clinicopathologic features, dose and outcomes were evaluated. Pts were staged using our previously published criteria: potentially resectable (PR), borderline type A (BR-A) (anatomy amenable to vascular resection), BR-B (biology suspicious for metastatic disease including high CA19-9), BR-C (co-morbidities requiring medical optimization), and LA. Co-morbidities were classified using adult comorbidity evaluation-27 score. Overall survival (OS) was analyzed using Kaplan Meier method. Results:99 pts [M/F: 50/49; median age: 70 yrs (range 30-85); PR/BR/LA: 45/14/40] were treated with Gem/nab-P. Clinical staging showed PR+BR-A/BR-B+C: 20/39. BR-B+C included one or more of the following factors: age ≥80 yrs [13%], ECOG PS ≥2 [13%], moderate/severe co-morbidities [55%], CA19-9≥1000 [28%], suspicion for metastatic disease [21%]. Majority of pts received biweekly Gem/nab-P dosing [standard/biweekly/other: 10/80/9] with minimal grade 4 toxicity. 45/99 pts received chemoradiation after Gem/nab-P [30Gy/50.4Gy: 15/30]. 12/20 (60%) PR+BR-A, 2/39 (5%) BR-B+C and 1/40 (3%) LA pts underwent pancreatectomy. 13/15 resected pts received adjuvant chemotherapy. At median follow-up of 26 mo, median OS was 18 (95% CI: 15.6-20.5) mo for all, 17 (95% CI: 14.6-19.5) mo for unresected and not reached for resected pts (p = 0.03). Conclusions: A significant number of pts with resectable PDAC albeit aggressive biology (BR-B) and/or medically inoperable disease (BR-C) received first-line Gem/nab-P; resection rates were lower compared to PR/BR-A pts. Biweekly dosing is being used in localized PDAC and is well tolerated.