Researchers have extended the lives of men with advanced prostate cancer by simply re-arranging the sequence in which they take their medication.
The benefits are so substantial it has been suggested this strategy should become a new standard of treatment.
When presented at the American Society of Clinical Oncology annual meeting in Chicago on Sunday, the result was described as unprecedented.
The strategy gives men an extra year of life, and more. This is highly unusual in adults with solid tumours whose cancer is already widely spread.
Outgoing ASCO president Clifford Hudis said he was not aware of any historical study that offered this magnitude of improvement in survival.
The strategy resulted from a trial funded by the prestigious US National Cancer Institute. It was stopped prematurely after an interim analysis showed a significant survival difference for the men using the new strategy.
The key was changing the usual order of hormone therapy and chemotherapy in men who have been newly diagnosed with metastatic prostate cancer – cancer that has spread to other parts of their body.
Traditionally, men receive hormone therapy first and when that fails they move on to chemotherapy.
Male hormones, known as androgens, promote the growth of advanced prostate cancer.
For more than 60 years, androgen deprivation therapy (ADT) has been routinely used to stop or slow this growth. But it only works for a while.
INCREASED LIFE EXPECTANCY
When it stops working, chemotherapy is given in the form of the drug docetaxel. But the study showed those men who received ADT and docetaxel together from the beginning of treatment lived about 14 months longer than those who initially received ADT only.
The length of survival was even greater for men who had high-extent disease, which means their cancer had spread to major organs and/or to their bones. They lived 17 months longer than those who initially received ADT only.
Overall, men who received the docetaxel lived nearly 58 months compared to 44 months for those not given the drug.
The meeting was told the new strategy also delayed men experiencing symptoms or discovering new areas of cancer spread by about 13 months.
Their blood markers for cancer, PSA, rose more slowly, their time to hormone resistance was lengthened and so was the progression of disease.
The study was conducted by the Dana-Farber Cancer Institute in Boston. It involved about 800 men who were newly diagnosed with metastatic hormone-sensitive prostate cancer. About two-thirds had high-extent disease.
Lead author Christopher Sweeney said this was first study to identify a strategy that prolongs survival for men with “newly diagnosed” metastatic prostate cancer.
“The benefit is substantial and warrants this being a new standard treatment for men who have high-extent disease and are able to have chemotherapy,” he said.
The results prompted comment about the importance of testing older medicines, like docetaxel, which are cheap and off patent.
Mark Frydenberg, president-elect of the Urological Society of Australia and New Zealand, said giving ADT and docetaxel together in high-risk cases was novel and seemed to have significant benefit.
“Obviously it would require further studies and validation in other centres but appears to be a promising strategy for high-risk cases,” he said.