Predictors of long-term survival with metastatic pancreatic cancer (mPC) in the gemcitabine era: The Fox Chase Cancer Center experience.

Abstract

253 Background: Although median survival (OS) for patients (pts) with mPC was ~6 months (m) in the gem era, a subset of pts lived significantly longer as long term survivors (LTS). We compared the patterns of care and outcomes of pts living < 12 m (Gp 1) and ≥ 12 m (Gp 2) to identify predictors for LTS. Methods: With IRB approval, we retrospectively analyzed medical charts of mPC pts treated at our center between 2000 and 2010. Gp 1 and Gp 2 were compared with respect to pt, tumor and treatment characteristics. Fisher’s exact and Mann-Whitney tests were used, respectively, to compare categorical and continuous variables, and the log-rank test to compare OS. All tests were two-sided and a Type I Error of 5% was used to determine statistical significance. Results: 579 mPC pts (median age 64 y, 56% males) were identified, 476 pts in Gp1 and 103 in Gp 2 (OS 4m vs 18 m, respectively). There was no significant difference in the age, site of pancreatic primary, comorbidities, tobacco use or stage at diagnosis between the two. 341 (72%) pts in Gp1 and 86 (83%) in Gp 2 had an initial PS <2 (p 0.06). Alcohol use was more prevalent in LTS [170 (36%) in Gp1 vs 50 (49%) in Gp2 (OR 1.8, p 0.008)]. 170 (36%) pts in Gp 1 and 55 (52%) in Gp 2 had serum albumin (alb) > 3.5 gm/dl (p< 0.001) and this predicted survival (OS 4m if Alb < 3.5 and 7m if Alb > 3.5, p <0.001). Use of chemotherapy in the metastatic setting (66% in Gp1 vs 93% in Gp 2) and number of agents used also predicted survival with 202 (42%) pts in Gp 1 and 79 (87%) in Gp 2 having received > one agent in the metastatic setting (p < 0.001). Liver metastases were more common as an initial site in Gp1 vs Gp2 [329 (70%) vs 48 (47%) respectively, p < 0.001]. In contrast, lung metastases were more common in Gp 2 [42 (9%) Gp 1 vs 20 (19%) in Gp 2, p< 0.001]. The median survival for pts with liver as initial metastatic site was worse than those with lung metastases (5m vs 7m, p < 0.001). Conclusions: Use of chemotherapy and increasing number of agents are associated with better survival in mPC, in line with the current practice of using combination chemotherapy. The site of initial metastasis and serum albumin also predict for survival. Clinical trial designs should consider the latter as stratification factors.