Long-Term Adverse Effects and Complications After Prostate Cancer Treatment.

Importance: Due to the often indolent nature of prostate cancer (PCA), treatment decisions must weigh the risks and benefits of cancer control with those of treatment-associated morbidities. Objective: To characterize long-term treatment-related adverse effects and complications in patients treated for PCA compared to a general population of older males. Design, Setting, and Participants: This cohort study used a novel approach linking data from 2 large PCA prevention clinical trials (the Prostate Cancer Prevention Trial and the Selenium and Vitamin-E Cancer Prevention Trial) with Medicare claims records. This analysis included patients with PCA who had been treated with prostatectomy or radiotherapy compared with an untreated control group. Multivariable Cox regression was used, with a time-varying covariate for the occurrence of PCA treatment, adjusted for age, race, and year of time-at-risk initiation, and stratified by study and intervention arm. Data analyses were performed from September 21, 2022, to March 18, 2024. Exposure: Prostatectomy and radiotherapy occurring after a PCA diagnosis, identified from trial data or Medicare claims records. Main Outcomes and Measures: Ten potential PCA treatment-related complications identified from Medicare claims data. Results: The study sample comprised 29 196 participants (mean [SD] age at time-at-risk initiation, 68.7 [4.8] years). Of these, 3946 participants had PCA, among whom 655 were treated with prostatectomy and 1056 with radiotherapy. The 12-year hazard risk of urinary or sexual complications was 7.23 times greater for those with prostatectomy (95% CI, 5.96-8.78; P < .001) and 2.76 times greater for radiotherapy (95% CI, 2.26-3.37; P < .001) compared to untreated participants. Moreover, among participants treated with radiotherapy, there was a nearly 3-fold greater hazard risk of bladder cancer than in the untreated (hazard ratio [HR], 2.78; 95% CI, 1.92-4.02; P < .001), as well as an approximately 100-fold increased hazard risk of radiation-specific outcomes including radiation cystitis (HR, 131.47; 95% CI, 52.48-329.35; P < .001) and radiation proctitis (HR, 87.91; 95% CI, 48.12-160.61; P < .001). The incidence per 1000 person-years of any 1 of the 10 treatment-related complications was 124.26 for prostatectomy, 62.15 for radiotherapy, and 23.61 for untreated participants. Conclusions and Relevance: This cohort study found that, even after accounting for age-related symptoms and disease, PCA treatment was associated with higher rates of complications in the 12 years after treatment. Given the uncertain benefit of PCA treatment for most patients, these findings highlight the importance of patient counseling before PCA screening and treatment and provide a rationale for pursuing opportunities for cancer prevention.