He C, et al. - In patients with second primary pancreatic ductal adenocarcinoma (PDAC), an aggressive and lethal disease with an annually increasing incidence, researchers evaluated the prognostic factors and assessed the survival impact of prior cancer using the Surveillance, Epidemiology, and End Results (SEER) database. Data were obtained from the SEER database of 9235 patients with PDAC from 2004 to 2015, consisting of 438 (4.74%) patients with prior cancer and 8797 (95.26%) patients without prior cancer, then pair-matched patients using propensity score matching (PSM) analysis. Investigators found that patients with PDAC who had previous cancer had similar rates of overall survival (OS) and cancer-specific mortality as patients without previous cancer. It should be considered the inclusion of patients with a prior cancer in PDAC clinical trials.