BRACHYTHERAPY is linked to a higher long-term risk of pelvic second malignancy compared to radical prostatectomy (RP), according to recent findings.
The authors conducted a retrospective review of patients treated with low-dose 125I brachytherapy and RP in British Columbia, Canada, from 1999–2010. The study assessed Kaplan Meier (KM) estimates for pelvic second malignancy (bladder and rectum), invasive pelvic second malignancy, any second malignancy, and death from any second malignancy. Cox multivariable analyses were adjusted for initial treatment type, age, post-RP adjuvant/salvage external beam radiation therapy status, and smoking history.
A total of 2,378 patients who underwent brachytherapy (median age: 66 years) and 9,089 patients who underwent RP (median age: 63 years), were included in the study. The KM estimates for pelvic second malignancy at 15 and 20 years were 6.4% and 9.8% after brachytherapy, respectively, and 3.2% and 4.2% after prostatectomy. Time to any second malignancy, and time to death from any second malignancy, were not significantly different (P>0.05) between the two groups.
Authors reported that, on Cox-multivariable analysis, brachytherapy, compared to RP, was an independent factor for pelvic second malignancy (hazard ratio: 1.81; 95% confidence interval: 1.45–2.26; P<0.001) and invasive pelvic second malignancy (hazard ratio: 2.13; 95% confidence interval: 1.61–2.83; P<0.001). Increased age and smoking were also associated with higher estimates of events (P<0.001). However, tobacco use was unknown in more than 60% of the RP group, compared to 5% of the brachytherapy group, which is a limitation of the study.
While second pelvic malignancy after external-beam radiation therapy for localised prostate cancer has been reported, data regarding brachytherapy have previously been conflicting. The authors highlighted the importance of continued screening and education in patients undergoing brachytherapy, especially for younger patients with long life expectancies following prostate cancer treatment.
Reference
St-Laurent MP et al. Long term second malignancies in prostate cancer patients treated with low-dose-rate brachytherapy and radical prostatectomy. J Urol. 2024;DOI:10.1097/JU.0000000000003965.
