Radical prostatectomy provides long-term benefits in clinically detected, localized prostate cancer
Radical prostatectomy can provide long-term survival benefits and reduce the risk of distant metastasis in otherwise healthy men with clinically detected, localized prostate cancer, according to findings from 23 years of follow-up of the SPCG-4 study (Scandinavian Prostate Cancer Group Study Number 4).
The current analysis included 695 patients randomized to undergo radical prostatectomy (n=347) or watchful waiting (n=348) between October 1989 and February 1999. After a median follow-up of 23.6 years, the cumulative incidence of death due to prostate cancer was 19.6 percent (n=71) in the radical prostatectomy group vs 31.3 percent (n=110) in the watchful waiting group. The relative risk vs watchful waiting was 0.55 (95 percent confidence interval [CI], 0.41 to 0.74; p<0.001), with an absolute difference in risk of 11.7 percent (95 percent CI, 5.2 to 18.2) and a number needed to treat of 8.4 to avert one death. [N Engl J Med 2018;379:2319-2329]
The cumulative incidence of death at 23 years was 71.9 percent in the radical prostatectomy group vs 83.8 percent in the watchful waiting group, with a relative risk of 0.74 (95 percent CI, 0.62 to 0.87; p<0.001) and an absolute difference of 11.9 percent (95 percent CI, 5.5 to 18.4).
“At 23 years, a mean of 2.9 extra years of life were gained with radical prostatectomy,” reported the investigators.
The cumulative incidence of distant metastases at 23 years was also lower in the radical prostatectomy vs watchful waiting group (26.6 percent vs 43.3 percent; relative risk, 0.54; 95 percent CI, 0.42 to 0.70; p<0.001).
“The effect of radical prostatectomy among men younger than 65 years of age at diagnosis was greater than that in men older than 65 years with regards to all three investigated endpoints,” the researchers noted.
In men aged <65 years at diagnosis, radical prostatectomy was associated with absolute risk reductions of 15 percent in overall mortality, 15.1 percent in mortality due to prostate cancer, and 18.6 percent in metastasis (relative risk, 0.62 [95 percent CI, 0.48 to 0.80], 0.50 [95 percent CI, 0.34 to 0.75], and 0.49 [95 percent CI, 0.34 to 0.70], respectively).
In men aged ≥65 years at diagnosis, the absolute risk reductions were 10.1 percent, 8.5 percent and 14.6 percent, respectively, while the relative risks were 0.86 (95 percent CI, 0.69 to 1.07), 0.63 (95 percent CI, 0.40 to 0.99), and 0.59 (95 percent CI, 0.41 to 0.86), respectively.
“Among men who underwent radical prostatectomy, extracapsular extension was associated with a relative risk of death from prostate cancer of 5.21 [95 percent CI, 2.42 to 11.22] compared with men without extracapsular extension,” the investigators reported.
Furthermore, a Gleason score of 8–9 was associated with a relative risk of death from prostate cancer of 10.63 (95 percent CI, 3.03 to 37.30) compared with a score of 3–6.“The patient’s life expectancy is an important factor to consider in decision making,” the investigators concluded. “When our results are applied to inform current practice, the lead time induced by screening, the addition to modern cohorts of overdiagnosed nonlethal cancers, and the influence of modern diagnostics on the definition of risk groups should also be considered. The amount of absolute benefit [from radical prostatectomy] is highly dependent on baseline risk.”