Combining radiation and hormone therapy appears to help men with advanced prostate cancer live longer than either treatment alone, concludes a new study published in The Lancet medical journal.
Between 15 and 25 per cent of the 25,500 new cases of prostate cancer diagnosed every year in Canada are considered high risk. Until this research, it had been assumed that most of those patients should be treated with hormone therapy alone.
That therapy, called androgen-deprivation therapy (ADT), is designed to curb the production of testosterone, the male sex hormone that fuels the growth of prostate tumours.
But this large new study led by Dr. Padraig Warde, a radiation oncologist at Toronto's Princess Margaret Hospital, found that many of these patients could benefit from radiation therapy as well.
Findings from the study were presented more than a year ago to a conference of clinical oncologists. The research has already begun to change the way that advanced prostate cancer patients are treated.
The study looked at more than 1,200 men from Canada, the U.S. and the U.K. with high-risk prostate cancer. All the men had cancer that had either spread to the area around the prostate gland or they had other high risk factors, such as a high PSA level.
Half were randomly chosen to be given the usual androgen deprivation therapy alone, while the other half received hormone therapy and external-beam radiation.
After seven years, 66 per cent of men who had hormone therapy only were still alive, compared with 74 per cent who received the combined therapy.
Among those in the hormone-only group, 26 per cent died from their prostate cancer, versus 10 per cent who received the hormone therapy and radiation combination.
Both hormone therapy and radiation therapy come with side effects. Hormone therapy can result in reduced libido and impotence, while radiation can cause bowel problems, bladder problems, urinary incontinence and impotence.
But the researchers say that combining the therapies can minimize the side effects because lower levels of radiation are required.
Warde says that radiation therapy is improving so that it can focus more precisely on the tumours, leading to fewer side effects.
"In the past, these patients were felt to be incurable and were treated with hormone therapy alone just to keep the cancer under control, but in fact the addition of radiation treatment in this study had a marked improvement in the cure rate," Warde told CTV News. "I think that is really a very significant finding."
He adds that he hopes now to get the message out to more clinicians who treat prostate cancer about the benefits of this combination therapy.
"I would say that it is a practice-changing study and I would hope that it is going to change lives," Warde says.
With a report from CTV's Avis Favaro and producer Elizabeth St. Philip
