Metastatic hormone-sensitive prostate cancer (mHSPC) can be treated with androgen-deprivation therapy (ADT) alone, ADT plus abiraterone, ADT plus enzalutamide, ADT plus apalutamide, ADT plus docetaxel. However, most patients eventually progress to castration-resistant prostate cancer (CRPC) and die of the disease. Therefore, there is still a need to improve the therapeutic effect for mHSPC.~Many studies have shown that metabolic syndrome and its components are associated with increased development and progression of aggressive prostate cancer. Metformin, a common well-tolerated oral biguanide prescribed for type II diabetes, could be used to decrease the risk of prostate cancer development and improve the efficacy of treatment. Some studies reported that metformin could enhance the effectiveness of ADT, and improve recurrence-free survival, overall survival and cancer-specific survival. A prospective randomized study reported that metformin potentially lengthen time to CRPC in advanced prostate cancer patients when combined with ADT especially in those with high risk localized prostate cancer, clinically node positive and in those with low tumor volume metastatic hormone-sensitive patients.~After extensive research, there is no published results from prospective randomized trials evaluating the effect of metformin in combination with ADT and abiraterone among patients with newly diagnosed mHSPC.
The purpose of this study is to assess the effect of the addition of metformin to abiraterone on survival in patients with newly diagnosed metastatic hormone-sensitive prostate cancer. The half the patients will receive metformin in combination with androgen deprivation therapy (ADT) and abiraterone, and the other half will receive ADT and abiraterone only.