Ten-year survival rates by PSA nadir in patients with metastatic hormone-sensitive prostate cancer: long-term survival analysis from the ECOG-ACRIN 3805 (CHAARTED) trial.

Background: The CHAARTED trial investigated the long-term survival of patients with metastatic hormone-sensitive prostate cancer (mHSPC) treated with androgen deprivation therapy (ADT) with or without docetaxel (D). This analysis focuses on 10-year overall survival (OS) stratified by disease volume and on-therapy PSA levels at 6 months.

Methods: OS was calculated using the Kaplan-Meier method from randomization to death or last known alive date. Patients were grouped based on baseline disease characteristics (high-volume/HV or low-volume/LV) and PSA levels at 6 months (<0.2 ng/mL vs. ≥0.2 ng/mL). Multivariable Cox regression analysis was used to evaluate correlation of PSA nadir with overall survival (OS) adjusted for treatment arm, disease volume, Gleason score, and prior local therapy.

Results: Of 790 patients, 225 were without recorded death after a median follow-up of 10 years. The 10-year OS was 25.9% (ADT+D) vs. 22.5% (ADT; HR: 0.78; p=0.004). HV patients treated with docetaxel had significantly higher OS (20.9% vs. 11.4%; p<0.0001). PSA <0.2 ng/mL at 6 months was associated with improved median OS in both ADT+D (100.3 vs. 45.4 months; p<0.0001) and ADT (116.8 vs. 31.8 months; p<0.0001) arms. PSA nadir <0.2 at 6 months was an independent predictor of improved OS (HR: 0.41; p<0.0001) adjusting for disease volume, prior local therapy, gleason score and treatment arm.

Conclusions: Long-term follow-up confirms that ADT+D significantly improves OS in mHSPC patients with in HV disease. PSA nadir <0.2 ng/mL at 6 months is a strong prognostic marker for OS, supporting its use in response-adapted de-escalation strategies.