Prostate cancer grows in response to testosterone. Testosterone can be blocked by injections which can be administered every 1, 3 or 6 months, by tablets or by removing the testicles. This can cause the prostate cancer to shrink back. It does not cure the cancer but holds it at bay. Primary hormonal therapy is usually reserved for patients who have other significant problems such that other radical treatments are not warranted. It may also be used in conjunction with radiotherapy or brachytherapy in some instances.