Background: In 2004, the European Study Group for Pancreatic Cancer (ESPAC)-1 long-term data concluded that adjuvant chemotherapy provided a survival benefit for patients with pancreatic ductal adenocarcinoma (PDAC), whereas adjuvant chemoradiation was associated with worse overall survival. In this study, we investigated how long it took for US practice patterns to change following this trial.
Methods: The National Cancer Database was used to identify patients with stage I-III PDAC who underwent R0 or R1 resection followed by adjuvant chemotherapy or chemoradiation between 1998 and 2015. A multivariate analysis was performed to determine predictors of receiving adjuvant chemoradiation in the post-ESPAC-1 era.
Results: Between 1998 and 2015, adjuvant chemotherapy use increased from 2.9% to 51.6%, whereas adjuvant chemoradiation decreased from 49.5% to 22.9%. In 2010, adjuvant chemotherapy utilization surpassed that of chemoradiation. For patients diagnosed in the post-ESPAC-1 era, adjuvant chemotherapy (n = 7733) and chemoradiation (n = 6969) groups were compared. Patients who underwent adjuvant chemoradiation were younger, had private insurance, underwent surgery at nonacademic centers, and had more pathologically advanced cancers (all P < 0.01). After 2010, R1 resection was the strongest independent predictor of adjuvant chemoradiation use by multivariate analysis (OR 2.05, CI 1.8-2.3, P < 0.01).
Conclusions: Adjuvant chemotherapy use exceeded that of adjuvant chemoradiation 6 y after the final publication of ESPAC-1 in 2004, highlighting the challenges of disseminating and adopting clinical data. After 2010, R1 disease was the most significant predictor of receiving adjuvant chemoradiation. Prospective studies are underway to definitively address the role of adjuvant chemoradiation in PDAC.
Keywords: Adjuvant therapy; ESPAC-1; Pancreatic cancer.
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