Study characterizes long-term impact of prostate cancer treatment

A recent study conducted by investigators from the SWOG Cancer Research Network shows that treatment for prostate cancer is associated with a higher risk of adverse effects and complications, even at 12 years following treatment.¹

The investigators assessed risk for 10 potential treatment-related complications.

This finding remained consistent even after accounting for age-related symptoms and disease of patients who received treatment vs those who were untreated.

“Past studies of prostate cancer treatment complications have had small sample sizes, limited follow up, or the absence of a valid control group,” said lead author Joseph M. Unger, PhD, MS, a biostatistician and health services researcher at Fred Hutchinson Cancer Center in Seattle, Washington, in a news release on the findings.² “Our study is distinguished by long follow-up, out to 12 years, looking at a broad spectrum of key complications. Critically, we were able to compare treated men to a representative control group of untreated men, which prior studies have not included.”

Overall, data for the cohort study were obtained from 2 large preventative trials––the Prostate Cancer Prevention Trial (PCPT) and the Selenium and Vitamin-E Cancer Prevention Trial (SELECT; NCT00006392). Data from the studies were linked to Medicare claims data.

In total, the analysis included 29,196 patients, of whom 3946 had prostate cancer. Among all patients with prostate cancer, 655 were first treated with prostatectomy and 1056 were first treated with radiotherapy.

The investigators assessed risk for 10 potential treatment-related complications, which included urethral stricture, placement of an artificial urinary sphincter (for severe incontinence), placement of a penile prosthesis, urinary incontinence, erectile dysfunction, radiation cystitis, radiation proctitis, bladder cancer, bladder cancer followed by cystectomy, and rectal cancer.

Findings showed that “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.”¹ This translates to a 6.57 times greater 12-year risk of having any 1 of these complications in the prostatectomy cohort and a 3.04 times greater risk in the radiotherapy cohort compared with participants who were untreated.

Looking at specific complications, patients who underwent prostatectomy had a 7.23-fold (95% CI, 5.96-8.78; P < .001) greater 12-year risk of urinary or sexual complications compared with untreated participants, and patients who underwent radiotherapy had a 2.76-fold (95% CI, 2.26-3.37; P < .001) greater risk.

Further, patients who underwent treatment with radiotherapy faced a nearly 3 times greater risk of bladder cancer vs untreated participants (HR, 2.78; 95% CI, 1.92-4.02; P < .001). These patients also had a 100-fold increased 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).

According to the authors, these findings highlight the importance of patient education both before treatment and before screening. They also recommend that quantitative information on the risks and benefits of treatment be included in national screening and treatment guidelines. This information is not currently included in any national guideline, according to the SWOG Cancer Research Network.²

Overall, the authors concluded, “Given the uncertain benefit of [prostate cancer] treatment for most patients, these findings highlight the importance of patient counseling before [prostate cancer] screening and treatment and provide a rationale for pursuing opportunities for cancer prevention.”¹

References

1. Unger JM, Till C, Tangen CM, et al. Long-term adverse effects and complications after prostate cancer treatment. JAMA Oncol. 2024.doi:10.1001/jamaoncol.2024.4397

2. Long-term risks from prostate cancer treatment detailed in new report. News release. SWOG Cancer Research Network. November 7, 2024. Accessed November 8, 2024. https://www.swog.org/news-events/news/2024/11/07/long-term-risks-prostate-cancer-treatment-detailed-new-report