Risk of second primary malignancies associated with radiotherapy in prostate cancer patients: competing risk analysis

Lay abstract Patients with prostate cancer have the highest 5-year survival rate, which increases the risk for developing second primary malignancies (SPMs). The effect of radiotherapy (RT) for SPMs is controversial among prostate cancer survivors. This study analyzed a mass of prostate cancer patients from a public database to compare risk for SPMs between RT and non-RT groups. RT indeed increased certain categories of SPM and intensive surveillance should be considered. Background: The effect of radiotherapy (RT) for second primary malignancies (SPMs) among prostate cancer survivors is controversial. Methods: Applying logistic regression, competing risk analysis and propensity score matching method, this study analyzed clinical data from the Surveillance, Epidemiology, and End Results program to compare the risk for SPMs between patients receiving RT and non-RT. Results: In this study, prostate cancer patients treated with RT developed more SPMs in the anus, bladder, rectum, liver, lung and bronchus and lymphoma than non-RT groups. Conclusion: More intensive surveillance should be adopted for these cancers among prostate cancer survivors.