Are Conservative Management Approaches to Low-Risk Prostate Cancer Catching On?

The use of active surveillance or watchful waiting (AS/WW) for low-risk prostate cancer (LRPC) has increased substantially in recent years, according to a new study published in Cancer. Outcomes with this approach have been good, though there is still a higher rate of AS/WW among older patients than younger patients.

“Conservative management of LRPC with AS/WW has been shown to be an efficacious alternative to definitive treatment and is now a National Comprehensive Cancer Network guideline-approved standard of care,” wrote study authors led by Brandon A. Mahal, MD, of the Dana-Farber Cancer Institute in Boston. “Although AS/WW can reduce overtreatment of indolent disease, concern about a greater risk of development of metastatic disease has led to reexamination of AS/WW for LRPC.”

Using non-public data from the Surveillance, Epidemiology, and End Results database, the researchers examined treatments and outcomes for 50,302 men diagnosed with LRPC from 2010 through 2015. Results of the analysis were published online ahead of print on June 28 in Cancer.

The cohort was divided into those aged 55 years and younger, and those aged 56 years and older. In the younger group, a total of 1,957 patients (19.6%) were treated with AS/WW, 6,041 patients (60.6%) underwent radical prostatectomy, and 1,975 patients (19.8%) underwent definitive radiotherapy. In the older group, 28.6% were managed with AS/WW, 35.9% underwent radical prostatectomy, and 35.5% underwent radiotherapy.

In both age groups, there was a marked increase in the use of AS/WW over time. The rate rose from 8.61% in 2010 to 34.56% in 2015 (P < 0.001) in those aged 55 years and younger; in the older patients, the use of AS/WW rose from 15.99% to 43.81% over that period (P < 0.001). The use of the definitive treatments decreased from 2010 to 2015.

Among men with two or fewer positive biopsy cores, the rate of AS/WW use rose from 12.90% in 2010 to 48.78% in the younger patients, and from 21.85% to 58.01% in the older patients. Among those with at least three positive cores, the rate of AS/WW rose from 3.89% to 22.45% in younger patients and from 10.05% to 28.49% in older patients (P < 0.001 for all).

On a multivariate analysis, several factors were associated with receiving AS/WW. Age of 56 years or above was a significant factor, with an odds ratio of 1.63 (95% CI, 1.54–1.72; P < 0.001), as were PSA increase, number of positive biopsy cores, and year of diagnosis.

Over a median follow-up period of 41 months, there were nine prostate cancer deaths among the younger patients (none with AS/WW, 9 with definitive treatment) and 64 among the older patients (11 with AS/WW, 53 with definitive treatment. There was no difference in prostate cancer-specific mortality by initial management (P = 0.40). The five-year prostate cancer-specific mortality rates were 0% in the younger AS/WW patients, 0.14% in the younger definitive therapy patients, 0.22% in the older AS/W patients, and 0.30% in the older definitive management patients. The five-year overall survival rates exceeded 98% in the younger patients, and 96% in the older patients.

“Our study demonstrates that there has been a rapid uptake of AS/WW as initial management, and AS/WW may be a reasonable approach for both younger and older patients with low-risk disease,” the authors concluded. “Despite a more rapid uptake of AS/WW in younger patients, there are still higher absolute rates of AS/WW in older patients, and radical prostatectomy remains the favored initial management approach for younger patients.”

In an accompanying editorial led by Andrew M. Fang, MD, of the University of Alabama at Birmingham, experts wrote that the use of active surveillance remains controversial in younger men. “This stems from concerns with the burden of continued follow-up, potential missed opportunities for cure, and the psychological burden of patients knowing they harbor a malignancy,” they wrote.

Still, improvements in recent years in imaging techniques has allowed active surveillance to be further refined, and studies suggest it is an effective management approach.

“As the body of literature continues to advance and technologies progress, the role of AS in the management of low-risk prostate cancer should continue to expand irrespective of the patient’s age,” the authors wrote.