Long-Term Second Malignancies in Prostate Cancer Patients Treated With Low-Dose-Rate Brachytherapy and Radical...

Area of Science:

• Urology
• Oncology
• Radiation Oncology

Background:

• Second malignancies are a rare but serious complication following prostate cancer treatment.
• Long-term data on the risk of second malignancies after prostate brachytherapy are limited.
• Understanding comparative risks between brachytherapy and radical prostatectomy (RP) is crucial for patient counseling.

Purpose of the Study:

• To estimate and compare the incidence of pelvic second malignancies after prostate brachytherapy versus radical prostatectomy (RP).
• To assess the long-term risk of developing secondary cancers in the pelvic region following these treatments.

Main Methods:

• Retrospective review of patients treated with low-dose ¹²⁵I brachytherapy or RP in British Columbia (1999-2010).
• Kaplan-Meier analysis for pelvic, invasive pelvic, any second malignancy, and death from any second malignancy.
• Cox multivariable analyses adjusted for age, smoking history, and post-RP treatment status.

Main Results:

• 15-year estimates for pelvic second malignancy were 6.4% after brachytherapy and 3.2% after RP.
• Brachytherapy was an independent factor for increased risk of pelvic (HR 1.81) and invasive pelvic (HR 2.13) second malignancies compared to RP.
• Increased age and smoking were also associated with higher risks of second malignancies.

Conclusions:

• Patients treated with brachytherapy showed numerically higher long-term risks of pelvic and invasive pelvic second malignancies compared to those treated with RP.
• These findings were observed after adjusting for key patient and treatment factors.
• The study underscores the need for careful consideration of long-term oncologic outcomes when selecting prostate cancer treatment.