Effective prostate cancer treatments live from the MOGA/FRO convention in Cairns

This morning, Professor Ian Tanner came over from Canada to present an overview of how prostate cancer has been treated up until now and where future treatments are going. The future looks promising for prostate cancer patients with new chemotherapy regimens showing both improved pain control and PSA, and use of biphosphonates for selected patients has proven useful for treating pain resulting from bone metastases.

Professor Ian Tanner from Canada presented a historical overview of prostate cancer treatment and reviewed some of the latest developments. In particular, he was looking at the disease known as hormone refractory prostate cancer. Prostate cancer usually responds well to hormonal agents but when it progresses this response can be lost. After failure of the hormonal agents there was previously not much choice but recent years have seen a number of exciting developments.When prostate cancer becomes hormone refractory, survival is usually short, approx 18 months.Previous standard treatment consisted of pain killers, laxatives and spot welding with targeted radiotherapy.Newer evolutions.Strontium 89 is a radioactive isotope chemically similar to calcium. This is then treated as calcium by the body and concentrated in bone, especially in the bone metastases. This kills the cancer cells and in some trials has advantage over targeted radiation for symptom relief. However, a significant problem is the thrombocytopenia (low platelet count) that often ensues.Chemotherapy trialsIn the first modern significant chemotherapy achievement for prostate cancer, the first Canadian Randomised Clinical Trial (RCT) randomized 161 patients to either prednisolone or mitoxantrone and prednisolone. The Primary end point was a 2 point reduction in a 6 point pain assessment scale.Although there was no improvement in survival in this small number of patients treated, there was a significant improvement in pain with 29% of patients improving compared to 12% with prednisolone alone. The time to progression of pain was also better being 24 weeks in the mitoxantrone group versus 10 weeks in the prednisolone group.Subsequent larger trials confirmed the benefits of this chemotherapy agent in selected patients. This then became the gold standard of chemotherapy care.Bisphosphonates, Any use??There has been considerable interest in the bisphosphonates as a way of palliating bone pain. The small trials of clodronate did not show any benefit. Zoledronate has also been trialed with a 3 week infusion of 8mg and 4mg. The 8mg was ceased due to renal toxicity and the 4mg produced a minor effect on bone events only (44% v 33% with placebo). This very modest difference was at the cost of mild overall increase in toxicity. Some specialists use Zoledronate to treat bone metastases in prostate cancer patients in selected patients.New Chemotherapy RegimensNewer chemotherapy treatment with a taxane, docetaxel, has shown the most promise. Early small trials with docetaxel demonstrated a 40 to 50% response of PSA and so a much larger RCT was undertaken involving 1006 patients. They were randomized to receive either docetaxel 75mg/m2 3 weekly, docetaxel 30mg/m2 weekly or mitoxantrone 12mg/m2. All were given prednisolone 10mg per day. Overall survival was better in the 3 weekly docetaxel group, being 19 months rather than 17 months for mitoxantrone. Median survival was 19 months v 16.5 with mitoxantrone.Symptomatically, 35% of the docetaxel 3 weekly treated group got improved pain control (21% mitox) and 45% got improved PSA (mitox 31%).There were a number of groups recognized that fared better than others. Your cancer specialist can advise you whether or not this treatment would benefit you.