ABSTRACT
Background: Androgen deprivation therapy (ADT) for prostate cancer (PCa) is accompanied by side effects affecting health-related quality of life (HRQL). Objective: To assess the effects of the fetal estrogen estetrol (E4) on symptoms related to estrogen and androgen deficiency, and on HRQL measured using the validated Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire. Design setting and participants: This was a phase 2, double-blind, randomized, placebo-controlled study in patients with advanced PCa. Intervention: Patients receiving ADT were randomly assigned at a 2:1 ratio to daily treatment with a high dose of E4 (HDE4; n = 41) or placebo (n = 21) for 24 wk. Outcome measurements and statistical analysis: The primary outcome was the effect of HDE4 cotreatment on hot flushes (HFs). Secondary outcomes were the Q-Man questionnaire for evaluation of the effect on estrogen and androgen deficiency symptoms, and the FACT-P questionnaire for evaluating HRQL. Results and limitations: At 24 wk, the number of patients experiencing HFs was significantly lower in the HDE4 group than in the placebo group (14.3% vs 60.0%; p < 0.001). HDE4 treatment was associated with lower incidence of night sweats, arthralgia, and fatigue, but more nipple tenderness and gynecomastia. At 24 wk, the mean HRQL score favored HDE4 over placebo for the FACT-P total score (122.2 ± 12.3 vs 118.7 ± 19.7) and for several other FACT subscales. Conclusions: Daily HDE4 coadministration almost completely prevented HFs in patients with advanced PCa treated with ADT. HDE4 also had positive effects on HRQL and counteracted other estrogen deficiency symptoms caused by ADT. These data support the dual efficacy concept of ADT and HDE4 to improve HRQL and increase the antitumor effect of ADT. Patient summary: For patients on androgen deprivation therapy for advanced prostate cancer, cotreatment with a high dose of estetrol almost completely prevents the occurrence of hot flushes and improves quality of life and well-being, but nipple sensitivity and an increase in breast size may occur.
ABSTRACT
BACKGROUND: Androgen deprivation therapy (ADT) for prostate cancer with luteinizing hormone-releasing hormone (LHRH) agonists can be improved. OBJECTIVE: To assess safety, the frequency and severity of hot flushes (HFs), bone health, and antitumor effects of high-dose estetrol (HDE4) when combined with ADT. DESIGN SETTING AND PARTICIPANTS: A phase II, double-blind, randomized, placebo-controlled study was conducted in advanced prostate cancer patients requiring ADT (the PCombi study). INTERVENTION: Patients receiving LHRH agonist treatment were randomized 2:1 to 40 mg HDE4 (n = 41) or placebo (n = 21) cotreatment for 24 wk. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Coprimary endpoints were frequency/severity of HFs and levels of total and free testosterone (T). Secondary endpoints included assessments of bone metabolism (osteocalcin and type I collagen telopeptide [CTX1]), prostate-specific antigen (PSA), and follicle-stimulating hormone (FSH). Efficacy analysis was based on the selected per-protocol (PP) population. RESULTS AND LIMITATIONS: Of 62 patients included in the study, 57 were suitable for a PP analysis (37 HDE4; 20 placebo). No E4-related serious cardiovascular adverse events occurred at 24 wk. Weekly HFs were reported by 13.5% of patients with HDE4 and 60.0% with placebo (p < 0.001). Daily HFs occurred in 5.9% versus 55%. Bone turnover parameters decreased significantly with HDE4 (p < 0.0001). Total and free T decreased earlier (p < 0.05), and free T was suppressed further (p < 0.05). PSA suppression was more profound and earlier (p < 0.005). FSH levels were suppressed by 98% versus 57% (p < 0.0001). Estrogenic side effects were nipple sensitivity (34%) and gynecomastia (17%). CONCLUSIONS: HDE4 cotreatment of ADT patients with advanced prostate cancer was well tolerated, and no treatment-related cardiovascular adverse events were observed at 24 wk. HFs and bone turnover were substantially reduced. Suppression of free T, PSA, and FSH was more rapid and profound, suggesting enhanced disease control by HDE4 cotreatment. Larger and longer-lasting studies are needed to confirm the results of the study reported here. PATIENT SUMMARY: Cotreatment of androgen deprivation therapy with high-dose estetrol in advanced prostate cancer patients results in fewer occurrences of hot flushes, bone protection, and other antitumor benefits. Nipple sensitivity and gynecomastia may occur as side effects.
