Combined radiation and hormone therapy best treatment for aggressive prostate cancer

01 June 2010

June 2010 – A study led by Canadian researchers has found that a combination of radiation and hormone therapy helps men with aggressive prostate cancer live longer.

The findings are expected to change clinical practice worldwide and challenge the currently accepted standard that hormone therapy alone should be the treatment of choice for aggressive prostate cancer. The findings were presented at the annual conference of the American Society of Clinical Oncology in June.

The results are at odds with what many clinicians have believed and practiced for many years, says Dr. Padraig Warde, who led the trial coordinated by the NCIC Clinical Trials Group (CTG) and the Medical Research Council in the United Kingdom. The CTG is funded by the Canadian Cancer Society.

Until now, most clinicians thought that patients with locally advanced prostate cancer should be treated with hormone therapy alone, says Dr. Warde, a radiation oncologist at Toronto’s Princess Margaret Hospital. The results of this clinical trial show that many of these patients could benefit from radiation therapy as well, he adds.

While combining radiation therapy with androgen-deprivation therapy (ADT) is already available at some treatment centres to some high-risk patients, it is not a worldwide standard. Most men receive the current standard therapy of just ADT to curb the production of testosterone – the male sex hormone that fuels the growth of prostate tumours.

The clinical trial involved 1,205 patients whose disease, at the time of diagnosis, had spread to the area around the prostate gland or who had other high risk factors, such as a high PSA level. About half the men were given the 2 therapies, while the other half received only hormone treatment. The study is one of the largest ever to test the effectiveness of this treatment method.

After 7 years of follow-up, 74% of men who had received the combination of radiation and hormone therapy were still alive, compared with 66 % of men who received hormone therapy alone. The combination treatment is particularly beneficial because the toxicity and related side effects are minimal due to lower levels of radiotherapy.

About 15 to 25 % of all newly diagnosed prostate cancer is locally advanced and therefore high risk. Dr Warde expects that the findings will lead to a change in the standard of care for this group of patients.

Prostate cancer is the most common cancer among Canadian men (excluding non-melanoma skin cancer). In 2010, an estimated 24,600 men will be diagnosed with prostate cancer and 4,300 will die of it.