Comparative Study Of Intermittent Versus Continuous Androgen Blockade In The Treatment Of Advanced Prostate Cancer

ObjectiveTo compare the efficacy and side effects of total intermittent androgen deprivation (IAD) versus total continuous androgen deprivation (CAD) for treating patients with advanced prostate cancer.MethodsThe study included 44 patients with advanced prostate cancer.Of them,21 patients (group IAD) received IAD therapy,and 23 patients (group CAD) underwent CAD,ie,surgical castration plus anti-androgen.The response to therapy and occurrence to disease progression was monitored by observing patients'prostate-specific antigen(PSA) and testosterone levels.Patients'quality of life also was measured by European Organization for Research and Treatment of Cancer Quality of Life Questionnaire PR25(EORTC QLQ-PR25).The time to prostate cancer progression,quality of life,and side effect rate were compared between the 2 groups.Results1.The mean follow-up period was 24 months(range,10-39 months)in group IAD and 22 months(range,9-36 months)in group CAD.The median time to disease progression was 36 months in group IAD and 30 months in group CAD,respectively.there was no significant difference between group IAD and CAD in the progression-free survival rate (P=0.132).2.The 21 patients treated with IAD completed 19 cycles.The mean cycle length was 15.9 months(time-on treatment and time-off treatment were 9.1 months and 7.6 months,respectively).The percentage of time-off treatment for each individual patient decreased and the disease progression rate increased with successive cycles.3.During the off-treatment period,scores of the patient in group IAD reflected improvement in treatment related symptoms over baseline levels during on-treatment period(P=0.007).But there was on significant difference between the two period in the urinary symptoms scores,bone pain scores,and bowel symptoms scores(P>0.05).After 5 months of androgen deprivation therapy,scores of the patient in group CAD reflected development in urinary symptoms over baseline levels in 5 months ago(P=0.007).But there were no significant changes in scores of bowel symptoms,treatment related symptoms,and bone pain(P>0.05).Side-effects were found in more patients of group CAD than in group IAD,including hot flash [60.9%(14/23) vs 28.6%(6/21),P<0.05];gynecomastia[52.2%(12/23) vs 19.0%(4/21),P<0.05].During off treatment period,patient treated with IAD experience improvement in hot flash and gynecomastia(P<0.05).But patinet treated with CAD experience remaining in these symptoms after 5 months of androgen deprivation therapy(P>0.05).ConclusionsIAD therapy is safe and feasible.It can minimize the negative effects of androgen deprivation therapy while maximize the clinical benefits and patients'quality of life.The efficacy of IAD therapy prolonging the time to androgen independence is equal to CAD therapy at least.Accordingly,Maybe IAD therapy is a better choice of androgen deprivation treatment for advanced prostate cancer.