Study results suggest prostate cancer classification of ‘very low risk’ may no longer be necessary

A recent University of California, San Francisco (UCSF) study found a decrease in patients meeting the criteria for “very low risk” (VLR) prostate cancer over time, with no patients meeting the criteria after 2018.

The findings were published in European Urology.¹

At the time of assessment, 364 (28.5%) of the 1276 initial patients met the NCCN VLR criteria.

Investigators conducted a retrospective analysis of patients diagnosed with prostate cancer from 2000 to 2020, yielding a total of 1276 patients with cT1–2 N0/x M0/x prostate cancer, prostate-specific antigen (PSA) level lower than 10 ng/mL, and biopsy Gleason grade group 1. All patients underwent active surveillance (AS) through UCSF.

For the study, VLR prostate cancer was defined using National Comprehensive Cancer Network (NCCN) criteria, which require that the disease is grade group 1, the patient has fewer than 3 positive cores—with 50% or lower cancer per core—and PSA density lower than 0.15 ng/mL/mL. The primary end point was upgrading on subsequent biopsy, which was defined as grade group 2 or higher.

At the time of assessment, 364 (28.5%) of the 1276 initial patients met the NCCN VLR criteria. The proportion of patients with VLR prostate cancer decreased over the study period, and there were no patients that met the criteria after 2018. This decrease was largely due to patients’ inability to meet the VLR requirement of having fewer than 3 positive cores over time. The median time to upgrade to grade group 2 or higher was 23 months.

Recently, the American Urological Association (AUA) merged the VLR and low-risk categories into a single category, but the National Comprehensive Cancer Network (NCCN) guidelines still include VLR as a subcategory in their classification. The authors urged the NCCN to revisit their inclusion of VLR as a subcategory for prostate cancer and consider replacing it with more contemporary risk stratification tools.

“In this study, we highlight a significant decrease in diagnoses of NCCN ‘very low risk’ prostate cancer at our high-volume prostate cancer center of excellence. We think this is an important call to action for the NCCN to follow in the footsteps of the AUA, who recently removed VLR from its prostate cancer guidelines in its most recent update, because there is no difference in preferred treatment compared to low-risk prostate cancers. (Both should receive active surveillance.) We further the rationale for its removal by showing that VLR prostate cancer is simply less relevant in the targeted biopsy area and should be replaced by more modern risk stratification tools,” said lead author Kevin Shee, MD, PhD, in an email to Urology Times®. Shee is a urology resident at UCSF.

The investigators also compared NCCN VLR classifications against scores from the UCSF multivariable Cancer of the Prostate Risk Assessment (CAPRA). Data showed that although NCCN VLR classification was not associated with upgrading on biopsy (P < .01), CAPRA score was associated with upgrading on biopsy (P < .01). The findings for both tools held even when controlling for patient age, genomic test results, and MRI findings.

Given that the CAPRA score effectively substratified patients over the same period and was able to predict upgrading on repeat biopsy to Gleason grade group 2 or higher (P < .01), the authors concluded that CAPRA scores or similar instruments could offer a potential alternative to the NCCN VLR subclassification for prostate cancer.

Reference

1. Shee K, Cowan JE, Balakrishnan A, et al. Limited relevance of the very low risk prostate cancer classification in the modern era: Results from a large institutional active surveillance cohort. Eur Urol. 2023 Mar 2;S0302-2838(23)02622-2. doi:10.1016/j.eururo.2023.02.013.