The following is a summary of “Clinical and treatment characteristics of secondary bladder malignancies following low dose rate brachytherapy for prostate cancer,” published in the June 2023 issue of Urologic Oncology by Chin et al.

The study aims to characterize the clinical course and prognosis of bladder cancers associated with prior prostate brachytherapy. Their institution’s database was queried for bladder cancer (BC) patients diagnosed between January 2005 and April 2019 who had undergone low dose rate (LDR) prostate brachytherapy. Patients diagnosed with BC were included at least one year after LDR prostate brachytherapy with or without external beam radiation therapy. Clinical and disease-specific characteristics were extracted from medical records, and Kaplan-Meier analysis was used to estimate survival outcomes. Researchers compared the pathologic features and prognosis of secondary BCs in their study cohort to those of BCs diagnosed after prostate cancer treated without radiation and reported to the Surveillance, Epidemiology, and End Results (SEER) population-based database between 2005 and 2018. 

About 375 patients with a combined diagnosis of prostate cancer and BC were identified, and 51 met the inclusion criteria for the study cohort. Study and SEER cohort median durations from brachytherapy to bladder cancer diagnosis were 9.5 ± 4.5 and 6.3 ± 4.1 years, respectively. In comparison to the SEER cohort, a substantially more significant proportion of BC from the study cohort presented as high-grade (study: 78.4%, SEER: 52.3%, P = 0.0008) and as MIBC (study: 35.3%, SEER: 17.3%, P = 0.0009). 5-year overall survival was comparable between the research and the SEER cohort (study: 67.9%, SEER: 58.0%, P = 0.1099), as was 5-year cancer-specific survival (study: 81.0%, SEER: 82.2%, P = 0.5559). 

The 5-year progression-free survival rate for the study population was 43.7% (95% CI: 28.8–57.8). Compared to bladder cancers caused by prostate cancer treated without radiation, bladder cancers caused by prostate LDR brachytherapy have a higher grade and are more likely to be muscle-invasive. Despite the aggressive presentation of BC after prostate brachytherapy, there were no disparities between the groups in terms of overall and cancer-specific survival.

Source: sciencedirect.com/science/article/abs/pii/S1078143922004914