One-half of patients with low-risk prostate cancer switch from active surveillance to active treatment

Nearly half of men initially managed with active surveillance for "low-risk" prostate cancer transition to definitive treatment – such as surgery or radiation therapy—within a few years after diagnosis, reports a study in The Journal of Urology, an Official Journal of the American Urological Association (AUA).

"These population-based data show that while the number of patients initiating active surveillance has significantly increased over time, follow-up shows a relatively high rate of transitioning to other forms of treatment within five years," comments senior author Antonio Finelli, MD, MSc, FRCSC, of University of Toronto. The study provides new evidence for how long patients can expect to remain on active surveillance, as well as factors affecting the likelihood of transition to definitive treatment.

'Real-world' data on uptake and discontinuation of active surveillance

Using Ontario health databases, the researchers analyzed 8,541 men with low-grade prostate cancer who were initially managed using active surveillance (mean age 64 years).

Active surveillance is used as a way to monitor slow-growing, "low-risk" or localized prostate cancer rather than treating it straight away. It typically involves regular prostate-specific antigen (PSA) screenings, prostate exams, imaging studies, and repeat biopsies in order to carefully monitor prostate cancer growth or progression without compromising long-term outcomes. The aim of active surveillance is to avoid or delay unnecessary treatment and its side effects.

"Unfortunately, despite the fact that most patients with low-risk prostate cancer are managed in community settings, limited real-world data are available on discontinuation rates of active surveillance for patients outside of academic institution cohorts," according to the authors. They used general population health data to evaluate trends in the uptake and discontinuation of active surveillance.

Overall, active surveillance was the initial management strategy for 51 percent of men diagnosed with low-risk prostate cancer. Use of active surveillance increased from 38 percent of patients in 2008 to 69 percent in 2014.

However, a median of four years after prostate cancer diagnosis, 51 percent of men had discontinued active surveillance and proceeded to definitive treatment including surgery, radiation, or hormone therapy—mainly due to signs of tumor progression. The percentage of men remaining on active surveillance decreased from about 85 percent at one year to 52 percent at five years.

Average time to definitive treatment was 16 months, mostly reflecting reclassification of patients early. The researchers emphasize that 49 percent of the men continued on surveillance, maintaining quality of life without disease progression.  

The researchers also looked at factors associated with the transition from active surveillance to definitive treatment. Transition was more likely for younger patients and those with certain higher-risk characteristics, such as higher PSA levels and more positive (showing cancer cells) biopsies.

Transition to definitive treatment was also more likely for patients with more accompanying medical conditions and those treated at academic medical centers or at hospitals treating a high volume of prostate cancer patients. Patients treated by urologists, rather than radiation oncologists, were more likely to remain on active surveillance. 

Dr. Finelli and coauthors believe their findings have important implications for management of low-risk prostate cancer, including patient counseling and setting realistic expectations for men considering their treatment options. They highlight the "dire need" to develop more specific tests and imaging studies to guide selection and monitoring of men who choose monitoring over immediate treatment for favorable-risk prostate cancer. Dr. Finelli adds, "Current practice may be improved by the development of quality indicators, targeted continuing education for physicians, and patient education with shared decision making at the onset of active surveillance."