The researchers followed Swedish, Finnish and Icelandic prostate cancer patients. Radical prostatectomy (surgical removal of the prostate gland) was performed on 347 randomly chosen male patients, while “watchful waiting” (careful monitoring combined with hormone treatment in cases of disease progression) was pursued with respect to 348 others. The men averaged 65 years of age when diagnosed with prostate cancer.
The results, which were analysed every third year, have significantly impacted how patients are treated today, both nationally and internationally. The study represents the only randomised investigation thus far to demonstrate that surgery reduces the risk of mortality from prostate cancer. The majority of the men had palpable tumours; 12 percent had non-palpable tumours that could only be identified using PSA (a marker for prostate cancer).
After 15 years, 48 per cent of the men in the surgical group had died, against 58 per cent in the watchful-waiting group. Of patients in the surgical group, 16 per cent died due to prostate cancer, against 23 per cent in the watchful-waiting group. The risk of cancer spreading beyond the prostate gland was 12 per cent lower for those who received surgery.
It was primarily younger men who benefitted from surgery. Analysis on the basis of age groups showed that men younger than 65 benefitted most. Among older men, there was no significant difference between the surgical group and the watchful-waiting group, presumably due to the fact that older men run a greater risk of mortality due to other illnesses, on account of which a much larger study would be required to show any difference.
The researchers also studied a group of men with tumours of the least aggressive kind (a low-risk group), even there finding differences in survival rate depending on whether surgery was performed. The low-risk group in question cannot, however, be perfectly compared with currently defined low-risk groups, and better markers will be required to determine the likelihood that low-risk tumours will assume a more aggressive form.
“The study shows that surgery reduces the risk of mortality due to prostate cancer, even for men with low-risk tumours,” says Anna Bill-Axelson, chief physician at the Department of Surgical Sciences at Uppsala University. “But not everybody benefits from surgery, so individual risks and potential gains have to be assessed on the basis of age, other illnesses, tumour type and patient preferences.”
Another finding of the study is that that surgical patients whose tumours had grown beyond the prostate gland ran a seven-times-greater risk of mortality due to prostate cancer than those whose tumours were limited to the prostate gland. The former group can greatly benefit from adjuvant treatment such as radiation therapy.
The most common side effects of surgical treatment were impotence and incontinence. More patients in the watchful-waiting group required ameliorative treatment due to tumor progression (hormone therapy) after a number of years. Both early side effects due to surgery and late side effects due to ameliorative treatment impact the quality of life of patients and must be part of discussions with patients about treatment options.
The study, designated “SPCG-4” (Scandinavian Prostate Cancer Group Study 4) was financed by the Swedish Cancer Society and, in recent years, also by the National Institutes of Health in the US.
A major study similar to the SPCG-4 study is currently under way in the US, with results expected soon. Another large study, comparing surgical, radiation-therapeutic and watchful-waiting outcomes in connection with localised prostate cancer, is under way in the UK.
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Read the article in the New England Journal of Medicine [Ref 1]. Radical Prostatectomy versus Watchful Waiting in Early Prostate Cancer, N Engl J Med 2011;364:1708-17.
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