Metastasis Rates Among Men on Active Surveillance for Prostate Cancer

Approximately 3% of men on active surveillance for prostate cancer were found to have metastasis by a median of 7 years after diagnosis, a recent study found.

Active surveillance is an approach put in place to manage low and low-intermediate risk prostate cancer (Gleason Score 6 or less with PSA 10 ng/ml or less), to help reduce harm from overtreatment and diagnosis.

The study, published in The Journal of Urology, analyzed 980 patients and found that 12.5% (211) were classified as intermediate risk, 11.1% (109) had a baseline PSA greater than 10 ng/ml, and 13.6% (133) had GS 7 disease. The median follow-up was 6.3 years (range 0.2 to 20.2).

The results of the study confirmed that active surveillance seems to be safe in patients who are low risk, and certain patients at intermediate risk.

Of the 980 participants, 3% developed metastasis. Additionally, 11 patients were found to be living with metastases at the end of the study, while 15 patients died from prostate cancer and 4 died from a different cause.

“The reported rate of 3% is a best case scenario and it is likely that many more men have metastatic disease,” said researcher Joel B. Nelson, MD.

There were 60% of patients who had metastases develop in the bone, while 43% saw development in the lymph nodes. In patients with GS 7 disease, the risk for metastasis increased to 10% in 13 of 133 patents.

“The researchers may be overly optimistic about the safety of surveillance, particularly in patients with Gleason 7 disease,” said researcher Michael O. Koch, MD. “Since median follow-up was only 6.3 years, the number of patients with Gleason 7 disease in whom metastases develop will grow even further. As of now active surveillance would appear to be ill-advised in this group of patients.”

During a diagnostic biopsy, patients who showed elements of Gleason pattern 4 had a threefold to fourfold increased risk for future metastasis when treated with an initial conservative approach.

“Such patients should be offered surveillance with caution,” said researcher Laurence Klotz, MD, FRCS(C) “Further evaluation with magnetic resonance imaging and/or genetic biomarkers should be strongly encouraged if surveillance is elected as an option in these patients.”

Although active surveillance is safe in prostate cancer patients who do not develop metastatic disease, further research needs to be done.

“Active surveillance is obviously safe in men who do not progress,” Nelson said. “The task now is to avoid misclassification of disease as indolent when it is not and detect progression before it is too late.”