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 (HSPC) treated with androgen deprivation therapy (ADT) with or without docetaxel (Taxotere). This analysis focuses on 10-year overall survival (OS) stratified by disease volume and on-therapy prostate-specific antigen (PSA) levels at 6 months.

PATIENTS AND

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 versus ≥0.2 ng/ml). Multivariable Cox regression analysis was used to evaluate correlation of PSA nadir with 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 + docetaxel) versus 22.5% [ADT; hazard ratio (HR) 0.78, P = 0.004]. HV patients treated with docetaxel had significantly higher OS (20.9% versus 11.4%, P < 0.0001). PSA <0.2 ng/ml at 6 months was associated with improved median OS in both ADT + docetaxel (100.3 versus 45.4 months, P < 0.0001) and ADT (116.8 versus 31.8 months, P < 0.0001) arms. PSA nadir <0.2 ng/l 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 + docetaxel significantly improves OS in metastatic HSPC patients with 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.