The results of the study, which appear in the New England Journal of Medicine, are controversial because medical opinions have long been divided about whether to surgically remove the prostate gland in the early stages of cancer or treat it with radiation or hormone therapy.
“When you remove the prostate gland, you get rid of the cancer but many men become impotent and some of them become incontinent. It’s very difficult to know how to best advise these patients,” the author of the study, Hans-Olov Adami, professor of cancer epidemiology at Sweden’s Karolinska Institute, told AFP.
Adami said however that his results clearly show that surgery gives patients the best chance of survival.
In the study, which began in 1989, 347 men diagnosed with prostate cancer underwent surgery, while 348 men with the cancer were placed in a control group which underwent radiation or hormone therapy.
In the surgery group 30 men died of prostate cancer, compared to 50 in the control group. And the benefits of the surgery seem to increase over time. Over the average 8.2-year observation period, 50 of the 347 men in the operation group developed new tumours, compared to 79 in the control group.
“Surgery reduces the mortality rate. But the absolute reduction is small: to save one life you have to operate 19 men,” Adami said.
He said the study was the first of its kind where a surgery group was compared to a control group.