Survival outcomes in prostate cancer patients with a prior cancer.

Background: To shed light on the survival outcomes of prostate cancer (PCa) patients diagnosed after a prior cancer and identify prognostic factors for overall survival (OS) and cancer-specific survival (CSS) in PCa patients.

Methods: In the primary group, a total of 1,778 PCa patients with a prior cancer were identified in the Surveillance, Epidemiology, and End Results (SEER) database from 2005 to 2015, retrospectively. Baseline characteristics and causes of death (COD) of these patients were collected and compared. In the second group, a total of 10,296 PCa patients [5,148 patients with PCa as the only malignancy and 5,148 patients with PCa as their second primary malignancy (SPM)] diagnosed between 2010 and 2011 were extracted to investigate the impact of prior cancers on survival outcomes.

Results: In PCa patients with a prior cancer, the most common type of prior cancer was from gastrointestinal system (29.92%), followed by urinary system (21.37%). Patients were more likely to die of the prior caner, and those with prior cancer from respiratory system had the worst survival outcomes. Moreover, the overall ratios in patients with stage (PCa) I-II and III-IV diseases were 0.21 and 1.65, indicating that patients with higher stage diseases were more likely to die of PCa. In the second group, patients with PCa as the SPM had worse OS than those with PCa as the first primary cancer. Lastly, prognostic factors for OS and CSS in PCa patients were explored.

Conclusions: PCa remains to be an important COD for patients with a prior malignancy, especially for those with high-stage diseases. PCa patients with a prior cancer had worse survival outcomes than those without.