WASHINGTON • The survival rate for early-stage prostate cancer is 99 per cent after 10 years, regardless of whether men undergo surgery, radiation or are "actively monitored", according to studies published this week.
Researchers hailed the results as good news, saying they had been expecting a survival rate of 90 per cent.
The two new studies, published in the New England Journal Of Medicine on Wednesday, also illustrated the complicated treatment equations facing men with early-stage prostate cancer, and they immediately set off a debate among physicians about how to interpret the results.
Researchers from the universities of Oxford and Bristol found no difference in survival rates among men who were randomly assigned to surgery, radiation or monitoring; it is the largest study of its kind.
Those who underwent surgery or radiation cut in half the risk that their disease would spread to bones and lymph nodes, compared with those who were simply monitored.
Researchers studied mortality rates at 10 years and whether the cancer progressed and spread; a second study addressed the impact of treatments reported by the men. Their conclusion was that the three approaches - surgery, radiation or actively monitoring - did not translate into "significant differences" in deaths caused by prostate cancer or other causes.
Although the treatment did not extend life during the first 10 years, a survival benefit might yet emerge in the next five or 10 years, the researchers said.
They also found that surgery and radiation treatments sometimes caused severe side effects, including sexual dysfunction, incontinence and bowel problems, that hurt the patients' quality of life.
"Men with newly diagnosed, localised prostate cancer need to consider the critical trade-off between the short-term and long-term effects of radical treatments on urinary, bowel and sexual function and the higher risks of disease progression" that come with monitoring, they wrote.
Professor Freddie Hamdy, a professor of surgery and urology at the University of Oxford who was the lead researcher, said his advice to patients is that they should not "rush to receive treatment, but to really digest and really look at the side effects that the treatments produce".
However, in an editorial that accompanied the studies, Dr Anthony D'Amico, chief of genitourinary radiation oncology at Brigham and Women's Hospital and the Dana-Farber Cancer Institute, emphasised the studies' finding that surgery and radiation reduced the risk of metastasis and disease progression.
The study looked at 1,600 men between 1999 and 2009. Researchers studied mortality rates at 10 years and whether the cancer progressed and spread; a second study addressed the impact of treatments reported by the men. Their conclusion was that the three approaches did not translate into "significant differences" in deaths caused by prostate cancer or other causes. "Thus," they concluded, "longer-term follow-up is necessary."
Dr Otis Brawley, chief medical officer for the American Cancer Society, who had no role in the study, noted: "This study has just 10 years of data, and it may take 20 or 25 years to see survival improvements from treatment, so we cannot say yet with certainty whether and how much of an advantage treatment has over no treatment. We can only say that at 10 years, there is no difference."