In a study reported in the Journal of Clinical Oncology, Harshman et al found that a prostate-specific antigen (PSA) level ≤ 0.2 ng/mL at 7 months after the start of androgen-deprivation therapy (ADT) was significantly associated with longer overall survival in metastatic hormone-sensitive prostate cancer, irrespective of receipt of docetaxel. The addition of docetaxel increased the likelihood of lower PSA and was associated with improved survival, as well.
E3805 CHAARTED Details
The study was a landmark survival analysis using data from 719 (of a total of 790) patients receiving initial treatment with ADT plus docetaxel (n = 358) or ADT alone (n = 361) in the E3805 CHAARTED trial. Inclusion in the analysis required ≥ 7 months of follow-up and PSA levels at 7 months from ADT initiation. PSA prognostic classifiers were ≤ 0.2, 0.2 to 4, and > 4 ng/dL.
PSA Levels Associated with Improved Survival
Median follow-up was 23.1 months. On multivariable analysis, 7-month PSA ≤ 0.2 ng/dL was more likely with docetaxel treatment, low-volume disease, prior local therapy, and lower baseline PSA (all P ≤ .01). Among all patients, median overall survival was 60.4 months among those with 7-month PSA ≤ 0.2 ng/dL vs 22.2 months among those with PSA > 4 ng/dL (P < .001). Corresponding median durations of survival were 60.4 months vs 25.2 months among patients receiving ADT plus docetaxel (P < .001) and 72.8 months vs 21.6 months among those receiving ADT alone (P < .001).
On multivariable analysis, 7-month PSA ≤ 0.2 ng/dL and low-volume disease were associated with longer overall survival (both P < 0.01). The addition of docetaxel increased the likelihood of achieving PSA ≤ 0.2 ng/dL at 7 months (45.3% vs 28.8% with ADT alone). Patients on ADT alone who achieved a 7-month PSA ≤ 0.2 ng/dL were more likely to have low-volume disease (56.7%).
The investigators concluded, “PSA ≤ 0.2 ng/dL at 7 months is prognostic for longer overall survival with ADT for metastatic hormone-sensitive prostate cancer, irrespective of docetaxel administration. Adding docetaxel increased the likelihood of a lower PSA and improved survival.”
The study was supported by grants from the National Cancer Institute and the Eastern Cooperative Oncology Group–American College of Radiology Imaging Network (ACRIN).
Christopher J. Sweeney, MBBS, of the Lank Center for Genitourinary Oncology at Dana-Farber Cancer Institute, is the corresponding author for the Journal of Clinical Oncology article.
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