Active surveillance (AS) is a durable management option for favorable-risk prostate cancer (PCa), with 64% of patients remaining on AS after 5 years, according to a population-based study of Swedish men.

Stacy Loeb, MD, of New York University, along with Pär Stattin, MD, PhD, and colleagues from the National Prostate Cancer Register of Sweden, looked at data from 11,726 men aged 70 years or younger in this comprehensive Swedish registry. The men were diagnosed with very low-risk to intermediate-risk PCa from 2003 to 2007 and had completed a 5-year follow-up.

By year 5, 36% of the men had discontinued AS, Dr. Loeb’s group reported online ahead of print in European Urology. Among men with very low-risk, low-risk, and intermediate-risk disease, the discontinuation rate by year 5 was 35%, 33%, and 41%, respectively.

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“In a population-based setting outside clinical trials, we demonstrate that AS is a feasible and durable management strategy to reduce PCa overtreatment while at the same time maintaining the chances of detection of high-risk PCa,” Dr. Loeb and her colleagues concluded.

Of 614 men who discontinued AS during follow-up, data on the reasons for discontinuation were available for 530 (86%). The reason was patient preference for 108 men (20%), PSA progression for 276 (52%), biopsy progression for 129 (24%), and other reasons for 17 (3%). For the men who discontinued AS for nonbiologic reasons, “there is a need for support and counseling for men to continue AS in the absence of signs of progression to improve adherence to AS and decrease overtreatment.”

In the subset of men who discontinued AS because of PSA progression, the median PSA level was 6.3 ng/mL at diagnosis and 9.8 ng/mL at discontinuation.

Of the men who discontinued AS, 68% underwent radical prostatectomy and 32% received radiation therapy.

The study also examined predictors of AS discontinuation. In multivariable analysis, compared with men younger than 60, men aged 65–70 years were 31% less likely to discontinue AS. The likelihood of discontinuing AS increased by 1% with each 0.1 ng/mL increment in PSA and decreased by 14% with each 1-unit increment in Charlson score. Men with T2 disease were 63% more likely to discontinue AS than those with T1 disease. A high level of education was associated with a 45% increased likelihood of discontinuing AS compared with a low level of education. “From a public health perspective,” the authors wrote, “it is critical to understand the underlying reasons for discontinuing AS,” Dr. Loeb’s group observed.

In their discussion of study strengths, the researchers noted that their “evaluation provides real-world data on the adherence to AS outside the confines of a specific protocol and on whether discontinuation was for biologic or nonbiologic reasons.” With respect to study limitations, they noted that they did not measure cancer-related anxiety, which prior investigations found to be a critical factor in AS adherence. In addition, data from Swedish men may not be generalizable to other populations with different healthcare systems and cultural backgrounds.