Safest for Favorable-risk Prostate Cancer: Surveillance

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Active surveillance may be the safest management strategy for men with favorable-risk prostate cancer, according to a new long-term study, which points to the value of surveillance over surgery or radiation for men with low-risk disease.

“Our study should reassure men that carefully selected patients enrolled in active surveillance programs for their low-risk prostate cancers are not likely to be harmed by their disease,” said H. Ballentine Carter, MD, Professor of Urologic Oncology and Director, Division of Adult Urology of the Brady Urological Institute at Johns Hopkins in Baltimore.

The study comes at an appropriate time because September is Prostate Cancer Awareness Month.

In the study, the men, median age 66 years, had a median follow-up of 5 years. Their risk level was determined, in part, by Gleason scores. Favorable-risk patients are defined as patients with a Gleason score of 6 or lower and a prostate-specific antigen level lower than 10 ng/mL.

Of the 1298 men, 47 died of non–prostate cancer causes, mostly cardiovascular disease; 9 of the 47 had received treatment for their prostate cancer. Two men died from prostate cancer, 1 after 16 years in the active surveillance program. In the second man’s case, Johns Hopkins doctors recommended surveillance, but the patient sought monitoring at another hospital and died 15 months after his diagnosis. Metastatic disease developed in 3 men.

The researchers calculated that overall men in the program were 24 times more likely to die from a cause other than prostate cancer over a 15-year span.

At 10-year and 15-year follow-up, overall survival was 93.2% and 68.7%, cancer-specific survival was 99.9% and 99.9%, and metastasis-free survival was 99.4% and 99.4%, respectively.

Slightly more than one-third of the men had prostate cancers that were reclassified to a more aggressive level within a median time of 2 years from enrollment in the active surveillance program.

For men with very low-risk cancers, the cumulative risk of a grade reclassification to a level that would have generally precluded enrollment in the program over 5, 10, and 15 years was 13%, 21%, and 22%, respectively. For men with low-risk cancers, this risk increased to 19%, 28%, and 31%.

Over the same time frames, the cumulative risk of a grade reclassification to a level that would be considered potentially lethal in most cases, but still curable, was no more than 5.9% for both very low and low-risk prostate cancers, Dr Carter said.

Also among the group, 109 men opted for surgical or radiation treatment despite the absence of significant change in their prostate cancer status.

Most of the men in the study were Caucasian, and Dr Carter cautioned that the outcomes may not apply to African-American men, who tend to have more aggressive cancers.

These data suggest that for men with an extended life expectancy of more than 15 years, active surveillance may be an acceptable management strategy.

“Our goal is to avoid treating men who don’t need surgery or radiation,” said Dr Carter. “The ability to identify men with the most indolent cancers for whom surveillance is safe is likely to improve with better imaging techniques and biomarkers.”