Adjuvant radiation may reduce the risk for all-cause mortality in a subgroup of men with very high-risk adverse pathologic characteristics at the time of radical prostatectomy for prostate cancer, new findings suggest.

Among 8362 men who underwent radical prostatectomy at a single center from 1987-2020, 926 men had grade group 4-5 disease with pT3a or higher stage and/or lymph node invasion. Among the 926 men, 538 (58%) received adjuvant radiation, 89 (10%) early salvage radiation therapy, and 299 (32%) observation alone for prostate cancer. The 10-year overall survival (OS) rate was 90%.

Multivariable Cox models showed that having more than 2 positive nodes (vs none) was significantly associated with a 2.1-fold increased risk for all-cause mortality, Elio Mazzone, MD, of IRCCS Ospedale San Raffaele in Milan, Italy, and colleagues reported in The Journal of Urology. Having 1-2 positive nodes (vs none) or Gleason Grade group 5 (vs 4 or less) were both significantly associated with a 1.8-fold increased risk of death. Pathologic stage T3b or higher disease was significantly associated with a 1.3-fold increased risk of death.

The investigators assigned a score to each adverse feature: 1 point for pT3b; 2 points for Grade Group 5 or 1-2 positive nodes; and 3 points for more than 2 positive nodes. Based on scoring, they defined novel subgroups: The novel high-risk group had 4 or more points; the intermediate-risk group had 2-3 points; and the low-risk group had 0-1 points.

Only the high-risk group benefited from adjuvant radiation therapy, which was significantly associated with a 57% improvement in 10-year overall survival compared with observation with or without early salvage radiation therapy (overall 10-year survival 76% vs 63%), the investigators reported.

Adjuvant Radiation Tx May Benefit Select Men With High-Risk Prostate Cancer

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