Normal preoperative endogenous testosterone levels predict prostate cancer progression in elderly patients after radical prostatectomy

Background: The impact of senior age on prostate cancer (PCa) oncological outcomes following radical prostatectomy (RP) is controversial, and further clinical factors could help stratifying risk categories in these patients.

Objective: We tested the association between endogenous testosterone (ET) and risk of PCa progression in elderly patients treated with RP.

Design: Data from PCa patients treated with RP at a single tertiary referral center, between November 2014 and December 2019 with available follow-up, were retrospectively evaluated.

Methods: Preoperative ET (classified as normal if >350 ng/dl) was measured for each patient. Patients were divided according to a cut-off age of 70 years. Unfavorable pathology consisted of International Society of Urologic Pathology (ISUP) grade group >2, seminal vesicle, and pelvic lymph node invasion. Cox regression models tested the association between clinical/pathological tumor features and risk of PCa progression in each age subgroup.

Results: Of 651 included patients, 190 (29.2%) were elderly. Abnormal ET levels were detected in 195 (30.0%) cases. Compared with their younger counterparts, elderly patients were more likely to have pathological ISUP grade group >2 (49.0% versus 63.2%). Disease progression occurred in 108 (16.6%) cases with no statistically significant difference between age subgroups. Among the elderly, clinically progressing patients were more likely to have normal ET levels (77.4% versus 67.9%) and unfavorable tumor grades (90.3% versus 57.9%) than patients who did not progress. In multivariable Cox regression models, normal ET [hazard ratio (HR) = 3.29; 95% confidence interval (CI) = 1.27-8.55; p = 0.014] and pathological ISUP grade group >2 (HR = 5.62; 95% CI = 1.60-19.79; p = 0.007) were independent predictors of PCa progression. On clinical multivariable models, elderly patients were more likely to progress for normal ET levels (HR = 3.42; 95% CI = 1.34-8.70; p = 0.010), independently by belonging to high-risk category. Elderly patients with normal ET progressed more rapidly than those with abnormal ET.

Conclusion: In elderly patients, normal preoperative ET independently predicted PCa progression. Elderly patients with normal ET progressed more rapidly than controls, suggesting that longer exposure time to high-grade tumors could adversely impact sequential cancer mutations, where normal ET is not anymore protective on disease progression.