Dear OncoLink "Ask the Experts,"
I am on Goserelin (Zoladex) for 3 months and one renewal before radiation. Please advise what is the optimal time of Goserelin before radiation?
Li Liu, MD, OncoLink Editorial Assistant, responds:
Thank you for your interest and question.
The question you raised is very common, and the answer remains controversial. For years, oncologists have been using androgen-ablation therapy (like Goserelin) for prostate cancer. The long-term use of androgen-ablation therapy has proven effective on short-term local control, disease free survival, and overall survival in selected patients with prostate cancer. A number of trials using different timings, dosings, and durations of hormone use have been conducted. The follow-up of those trials remains too short to draw any definitive conclusions.
The Radiation Therapy Oncology Group (Journal of Clinical Oncology, 15:1013-1021, 1997) reported a randomized phase III trial (Protocol 8531) of adjuvant Goserelin in definitively irradiated patients with organ confined prostate cancer. Patients were randomized either to radiotherapy and adjuvant Goserelin (arm I) or to radiotherapy alone followed by observation and application of Goserelin at the time of relapse (arm II). This study demonstrated significant improvement in local control and freedom from disease progression with adjuvant androgen suppression using Goserelin (Arm I). However, the median follow-up time was only 4.5 years. A Canadian trial reported by Dr. Laverdiere (International Journal of radiation Oncology, biology, and Physics, 37:247-252, 1997) randomized patients between external beam radiation therapy alone (group 1), 3 months of hormone prior to radiation (group 2), and a third group receiving hormone 3 months before, during, and 6 months after radiation. The preliminary results suggest that patients treated with radiation therapy alone (Group I) had a significantly higher rate of positive biopsies at 12 and 24 months after the end of radiation therapy. No comparison was made between group 2 and 3.
Longer follow-up and more trials will be needed to determine the true role of androgen-ablation therapy as a complement to local prostate therapy. You should talk to your doctor regarding hormonal therapy.