New Protocol of Intermittent Androgen Deprivation Therapy for Patients With Metastatic Prostate Cancer: A Retrospective Study.

Abstract

The optimal points for halting and resuming treatment in intermittent androgen deprivation therapy (IADT) for metastatic prostate cancer patients are controversial. In the 65 metastatic prostate cancer patients in group 1, androgen deprivation therapy was stopped when prostate-specific antigen (PSA) levels reached a nadir and was resumed when PSA levels doubled and≥ 1.0 ng/mL (new protocol). In the 62 patients in group 2, androgen deprivation therapy was stopped 3 months after PSA= 0.2 ng/mL and resumed at PSA≥ 4.0 ng/mL (Chinese Urological Association guideline). The total IADT duration, overall on-treatment and off-treatment time, tumor clinical progression ratio, performance status improvement, and treatment-related adverse effects were retrospectively analyzed. In groups 1 and 2, the median total IADT durations were 51 and 46.5 months (significant difference, P= .006), median overall on-treatment times were 28 and 27.5 months (no significant difference, P > .05), and median overall off-treatment times were 23 and 19 months (significant difference, P< .001), respectively. Multivariate Cox regression analysis indicated that patients in group 1 had significantly higher progression-free-survival (hazard ratio, 0.634; P= .014). Two cases of clinical progression occurred group 1 and 5 in group 2; there was no significant difference (P > .05). There were no significant differences between the groups in terms of performance status improvement and treatment-related adverse effects. The new protocol was found to be beneficial, showing less biochemical/clinical progression, satisfactory performance status, and acceptable treatment-related adverse effects.