AB37. The combination of I brachytherapy with intermittent androgen deprivation in treating locally advanced prostate cancer

Objective: To evaluate the clinical efficacy of combination of intermittent androgen deprivation and I brachytherapy (BT) for the treatment of locally advanced prostate cancer.

Method: A total of 31 patients with locally advanced prostate cance were treated with the Combination Of I Brachytherapy and Intermittent Androgen Deprivation. Bicalutamide 50 mg Qd and Goserelin 3.6 mg every 28 days were given after surgery. When PSA fell to 0.1 ng/mL and stabilized for two months, treatment was stopped (off phase). A PSA relapse was defined according to the ASTRO consensus definition (PSA was more than 0.5 ng/mL and three successive PSA elevations after a post-operation nadir was achieved). When the PSA relapse happened, hormonal therapy was restarted.

Results: All cases were followed up 12-65 months average 35 months. All the patients’ PSA fell to the normal range (≤4 ng/mL) 3 to 5 months after operation. A total of 28 patients’ PSA decreased to <0.1 ng/mL and stopped hormonal therapy. Three cases did not reach standard, so they maintained the hormonal therapy. A total of 7 of the 28 patients suffered the PSA relapse 5 to 26 months after stopping hormonal therapy. Hormonal therapy was restarted and the PSA decreased to 0 ng/mL again in 5 cases of the 7 PSA relapse patients. A total of 21 of the 31 patients did not suffer the PSA relapse during the follow up. The duration of first off phase was 12-57 months, averaging about 26.9 months. Bone metastasis happened in two patients. One patient was diagnosed as bone metastasis 16 months after operation. One patient was diagnosed as bone metastasis and died 42 months after operation.

Conclusion: Combination of intermittent androgen deprivation and I brachytherapy is an effective and safe treatment for locally advanced prostate cancer. Our results need to be approved by multicenter prospective randomized trial.

Keywords: I brachytherapy; prostate cancer (PCa); androgen