Caution: Active Surveillance Ill Advised in Men with Intermediate-Risk Prostate Cancer
Orlando, FL—Active surveillance is sometimes used as management strategy in patients with intermediate-risk prostate cancer, especially in older, sicker men with short life expectancy. A new study validates the use of active surveillance for men with low-risk prostate cancer but provides sobering data regarding this type of management for those with intermediate-risk prostate cancer. The study results were presented at the 2015 Genitourinary Cancers Symposium.
Surveillance Can Increase Mortality
The study findings showed that intermediate-risk patients had almost a 4-fold higher risk for dying from prostate cancer compared with patients with low-risk prostate cancer when managed by active surveillance.
“This is the first study to analyze long-term outcomes of intermediate-risk patients managed by active surveillance. This study validates active surveillance for low-risk patients with prostate cancer. We were surprised by the greater risk of prostate cancer death in the intermediate-risk patients assigned to active surveillance,” stated senior investigator, D. Andrew Loblaw, MD, MSc, of the Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Lead investigator Hima Bindu Musunuru, MD, of the Sunnybrook Health Sciences Centre, said, “Extreme caution should be exercised if active surveillance were to be implemented for intermediate-risk patients.”
Dr Loblaw said that further study is needed to define favorable versus unfavorable intermediate-risk patients. “We think there may be a subgroup of intermediate-risk patients out there who may be safely managed by active surveillance,” he stated.
The prospective study included 945 patients with prostate cancer who were managed with active surveillance between 1995 and 2013 at Sunnybrook Health Sciences Centre; 237 (23.9%) patients had intermediate-risk disease and a median follow-up of 6.9 years, and 708 patients had low-risk prostate cancer and a median follow-up of 6.4 years. The median treatment-free interval for intermediate-risk patients was 12.3 years.
Patients with progressive disease, as reflected by a prostate-specific antigen doubling time of <3 years, were offered radiation or surgery; 86 patients with intermediate-risk prostate cancer received treatment.
For patients with intermediate-risk prostate cancer, the 10- and 15-year overall survival rates were 68.4% and 50.3%, respectively, versus 83.6% and 68.8%, respectively, for low-risk patients (P <.001).
The 10- and 15-year cancer-specific survival was 95.5% and 88.5%, respectively, for the intermediate-risk group, and 98.2% and 96.3%, respectively, for the low-risk patients (P = .006).
Just under 66% of the intermediate-risk patients were aged >70 years. In the study, active surveillance was offered to men with shorter life expectancy and comorbidities, which is in line with the current National Comprehensive Cancer Network guidelines.
The risk for dying from any cause was twice as high for intermediate-risk patients compared with low-risk patients. Moreover, the risk for prostate cancer–specific death at 15 years was 3.75 times higher for intermediate-risk patients compared with low-risk patients at the same time point (11.5% vs 3.7%, respectively).
The field of molecular and biological markers for intermediate-risk prostate cancer is an active area of investigation, according to Dr Loblaw and American Society of Clinical Oncology Expert and 2015 Genitourinary Cancers Symposium News Planning Committee team member Charles Ryan, MD, of the University of California, San Francisco.