Prostate Cancer Deaths in PSA-Detected Disease Remained Low at 15 Years

Long-term follow-up data from the phase 3 ProtecT trial suggest that prostate cancer–specific mortality following detection of localized disease with prostate-specific antigen (PSA) testing was low regardless of treatment method at 15 years of follow-up. The findings, which highlight the importance of weighing the risks associated with different prostate cancer treatment options, were published in the New England Journal of Medicine. 

PSA testing has significantly increased the early detection of prostate cancer, but the optimal management strategy for localized prostate cancer can be difficult to determine, the authors noted. When a patient presents with indolent disease, the potential harmful effects of treatment must be carefully considered.

The ProtecT trial aimed to evaluate the efficacy of conventional prostate cancer treatments in disease identified via PSA testing. Of 2664 men in the study cohort who had localized disease, 1643 were randomized to receive active monitoring (n = 545), prostatectomy (n = 553), or radiotherapy (n = 545). The median age at prostate cancer diagnosis was 62 years, and the median PSA level was 4.6 n/mL.

The new analysis included 1610 men with a life expectancy of at least 10 years at diagnosis who had full follow-up data available at a median follow-up of 15 years. Researchers aimed to assess the efficacy of each treatment method in terms of prostate cancer–specific and all-cause mortality, metastases, disease progression, and the initiation of long-term androgen-deprivation therapy in this population.

In 1999, when the ProtecT trial was initiated, 77.2% of cancers were Gleason grade group 1 and 76.0% of men had stage T1c cancer. But modern risk-stratification models showed that up to 34% of the cohort had intermediate or high-risk prostate cancer at baseline.

Researchers found that in the active monitoring, prostatectomy, and radiotherapy groups, 17, 12, and 16 patients died from prostate cancer, respectively. A total of 356 men died from any cause (21.7%), and the numbers were similar across treatment groups.

Fifty-one patients (9.4%) in the active monitoring group developed metastases compared with 26 (4.7%) in the prostatectomy group and 27 (5%) in the radiotherapy group. Sixty-nine (12.7%) men in the active surveillance group, 40 (7.2%) in the prostatectomy group, and 42 (7.7%) in the radiotherapy group initiated . In the monitoring, prostatectomy, and radiotherapy groups, clinical progression occurred in 141 (25.9%), 58 (10.5%), and 60 (11.0%) patients, respectively.

“Radical treatments (prostatectomy or radiotherapy) reduced the incidence of metastasis, local progression, and long-term androgen-deprivation therapy by half compared with active monitoring,” the authors wrote. “However, these reductions did not translate into differences in mortality at 15 years, a finding that emphasizes the long natural history of this disease.”

A total of 133 individuals (24.4%) in the active monitoring group were alive and had not received any treatment for prostate cancer by the end of the follow-up period.

Baseline risk-stratification score, PSA level, and disease stage or grade did not affect cancer-specific mortality in the cohort. Additionally, there were no reported treatment complications following a 10-year analysis.

Overall, mortality at a median follow-up of 15 years was very low across the active monitoring, prostatectomy, and radiotherapy treatment groups despite some improvement in the risk of disease progression when radical treatments were implemented.

“Our findings indicate that depending on the extent of side effects associated with early radical treatments, more aggressive therapy can result in more harm than good,” the authors wrote. “Clinicians may avoid overtreatment by ensuring that men with newly diagnosed, localized prostate cancer consider critical trade-offs between short-term and long-term effects of treatments on urinary, bowel, and sexual function, as well as the risks of progression.”

Reference

Hamdy FC, Donovan JL, Lane A, et al. Fifteen-year outcomes after monitoring, surgery, or radiotherapy for prostate cancer. N Eng J Med. Published online March 11, 2023. doi:10.1056/NEJMoa2214122