Cancer-specific mortality in high-risk or very high-risk prostate cancer patients treated with cryotherapy vs. external beam radiation therapy.

INTRODUCTION: Cryotherapy in high-risk or very high-risk prostate cancer (PCa) is not guidelines recommended, but it is occasionally used outside of formal clinical trials. However, its effect on cancer-specific mortality (CSM) relatively to standard treatment options such as external beam radiation therapy (EBRT) is unknown and was addressed in the current study. METHODS: In the Surveillance, Epidemiology, and End Results (SEER) database (2010-2022), high-risk or very high-risk PCa patients according to the National Comprehensive Cancer Network (NCCN) guidelines, treated with either cryotherapy or EBRT were identified. Univariable competing risks regression (CRR) models, after 1:1 propensity score matching (PSM), tested for CSM differences after accounting for other-cause mortality (OCM) as a competing event. RESULTS: Overall, 33,961 high-risk or very high-risk PCa patients treated with cryotherapy or EBRT were identified. Of those, 245 (0.7%) underwent cryotherapy and 33,716 (99.3%) EBRT. In 1:1 PSM, 245 cryotherapy patients were matched with one EBRT control. After 1:1 PSM, at 120-months of follow-up, CSM after EBRT was 7.7% vs. 16.7% after cryotherapy. The corresponding OCM rates were 32.2% after EBRT vs. 32.1% after cryotherapy. In univariable CRR models, accounting for OCM, cryotherapy increased CSM in a 2.2-fold fashion (HR: 2.20; 95% CI: 1.15-4.17; p = 0.017). CONCLUSION: Despite lack of guidelines endorsement, occasional high-risk or very high-risk PCa patients are treated with cryotherapy at large. Population-based observations indicate that cryotherapy is associated with a higher risk of CSM compared with EBRT in these patients.