Study Following A Steroid Switch From Prednisone To Dexamethasone In Castration-resistant Prostate Cancer Patients Progressing On Abiraterone

Objective:To evaluate the clinical efficacy and biochemical transformation of conversion of prednisone to dexamethasone combined with abiraterone after PSA progression in patients with castration-resistant prostate cancer(CRPC).Methods:From May 2015 to October 2018,201 patients with CRPC were admitted to the First Affiliated Hospital of Ji Nan University and Sun Yat-sen University Cancer Center.They were treated with 1 000 mg of abiraterone once a day and 5 mg of prednisone twice a day.After PSA progression,prednisone was changed to 0.5mg of dexamethasone once a day in 31 patients.The serum prostate specific antigen(PSA)efficiency and toxicity were observed.The difference between PSA decline ≥50% and PSA decline < 50% was compared,and the PSA PFS of patients with abiracetone combined with dexamethasone was analyzed by kaplan-meier.The Cox regression model was used to analyze the influencing factors of PSA PFS by univariate and multivariate analysis.Results:(1)31 patients were followed up for 2.10～7.80 months.The median follow-up time was 4.9 months.The remission rate of PSA decreased by more than 50% was 19.4%.The median PFS of AA+D was 3.83 months(95%CI: 2.74-4.92).The PSA PFS of patients with PSA decreased by more than 50% was 4.03 months(95%CI: 1.11-6.95),and the PSA PFS of patients with PSA decreased less than 50% was 3.13 months(95%CI: 2.01-4.26).(2)Unifactorial analysis results showed that ALP ≤ 125U/L and PSA < 50ng/ml at dressing change were influential factors for the good prognosis of PSA PFS in patients with AA+D.Multivariate analysis results suggested that ALP>125U/L was an independent prognostic risk factor for PSA PFS.(3)AA+D was well tolerated,and there were no grade 3 and grade 4 adverse events.The main side effects were edema,hypokalemia and hypertension.Conclusion:Conversion of prednisone to dexamethasone in the treatment of resistant prostate cancer(CRPC)patients using abiraterone prolonged PSA PFS.ALP>125U/L at dressing change is an independent risk factor for the prognosis of PSA PFS.Meanwhile,with good tolerance and safety,it is an alternative treatment plan that such patients can choose,but the long-term efficacy and side effects also need to be confirmed by large sample prospective study.