Phase 3 clinical trial comparing intermittent hormonal therapy and continuous hormonal therapy in patients with advanced prostate cancer

The present study compared the effectiveness of two kinds of hormonal therapy in advanced prostate cancer (cancer that has spread beyond the prostate gland). These are intermittent hormonal therapy (IHT) and continuous androgen-deprivation therapy (ADT). In this study, IHT was similar to ADT in terms of survival, but showed better quality of life in patients with advanced prostate cancer (PCa).

PCa needs male hormones (androgens) to grow. Hormonal therapy (also known as ADT) lowers the amount of androgens in a man’s body, thus slowing the growth of PCa. However, the lower level of male hormones due to ADT has side effects such as sexual problems, hot flushes and enlargement of the breasts which may influence the patients’ quality of life. Currently, ADT is considered to be the standard therapy for advanced PCa. To increase the effectiveness of ADT and decrease side effects, many patients may choose alternate treatment such as IHT in between ADT cycles. However, no study to date has reported the use of IHT with anti-androgens (cyproterone acetate) as single treatment option in advanced PCa. 

This phase 3 clinical trial included 918 PCa patients. 462 patients were randomly assigned to receive IHT and 456 patients received ADT. The main parameters measured were overall survival or OS (defined as the percentage of patients who have survived for a certain period of time), side effects and quality of life. After approximately 12 years of follow up there was a 10% higher OS for patients in the IHT group compared to ADT. IHT was more effective than ADT in patients with a PSA (a protein specific to the prostate whose level rise in prostate disease) of 1 ng/ml or lower, with a 21% higher OS. Side effects such as hot flashes, breast enlargement, headaches or skin reactions were more common in the ADT group than the IHT group. An improvement in sexual activity was reported with those treated with IHT.

In summary, with regard to OS and quality of life, IHT is as effective as continuous ADT in patients with advanced PCa. IHT showed improved sexual function and quality of life in PCa patients.