Impact of prior cancer on the overall survival of patients with nasopharyngeal carcinoma.

PURPOSE Prior cancer history is an important exclusion criterion from clinical trials and may decrease their generalizability. This study aimed to investigate the impact of prior cancer on the prognosis of patients with nasopharyngeal carcinoma and to describe their characteristics. MATERIALS AND METHODS Data of patients with nasopharyngeal carcinoma diagnosed between 2010 and 2015 were collected from the Surveillance, Epidemiology, and End Results database. The discrepancy in baseline characteristics was adjusted by propensity score matching. Kaplan-Meier and Cox regression analyses were performed to assess the impact of prior cancer on overall survival. RESULTS A total of 3412 individuals were identified, of which 418 (12.25%) had prior cancer. Prostate cancer was the most frequently detected type of prior cancer (18.42%). Nearly 45% of the prior cancers were diagnosed within 5 years before the nasopharyngeal carcinoma. Patients with prior cancer had an inferior survival compared to those without prior cancer (p < 0.001). Notably, patients with prior prostate, breast, hematological, and nasopharyngeal cancers had a non-inferior overall survival. Prior cancer history was an independent factor of poor overall survival (hazard ratio = 1.329, p = 0.003). CONCLUSIONS This is the first study to provide the comprehensive insight that patients with nasopharyngeal carcinoma and prior cancer have lower overall survival. Different prior cancer types had a different impact on the clinical outcome, suggesting that the exclusion criteria should be individually defined by unique cancer types.