After definitve treatment of prostate cancer, whether by surgery or radiation, a certain percentage of men will have a rising PSA. This implies residual or recurrent cancer. The recurrence can either be in the pelvis, or distant spread. In some men, all that is required is to follow the PSA closely every 3 months to see what will happen. In other men, androgen ablation is needed. This is tablets and/or injections of drugs that suppress testosterone. When testosterone production is suppressed, this halts the growth of prostate cancer cells for a certain period of time. The controversy is “when is the best time to start this treatment”. Androgen ablation carries many untoward side effects and reduces quality of life. They include; reduced libido, fatigue, loss of muscle mass, obesity, diabetes, osteoporosis, cardiac problems including coronary artery disease, altered lipid profile, mental changes, breast tenderness or pain, and hot flashes. We use “triggers” to determine the best time to start hormonal therapy. If the PSAdt (doubling time) is rapid (<6 months), or the PSA never reached a low nadir (a low level), or the PSA never was <0.01, then one could argue to commence hormones early. If the Gleason grade was 8 or higher, or lymph node in the pelvis were positive, these are other reasons to start hormones early. Thre is a consensus that waiting for bone metastases on a bone scan is too late. Some urologists use a PSA cut-off of greater than 0.4 ng/ml, while others use a cut-off of PSA >5 ng/ml. Each case must be individualised, and often a multi-disciplinary approach is needed in consultation with a radiation and medical oncologist.