Bruno Nahar, Andrew Katims, Marcelo Panizzutti Barboza, Nachiketh Soodana Prakash, Vivek Venkatramani, Bruce Kava, Ramgopal Satyanarayana, Mark L. Gonzalgo, Chad R. Ritch, Dipen J. Parekh, Sanoj Punnen

To evaluate the impact of adding MRI-US fusion biopsy cores to standard 12-core biopsy in selecting men for Active Surveillance(AS). Among men undergoing a fusion biopsy for evaluation of prostate cancer, we selected men who were eligible for at least one of seven different AS criteria based on the standard biopsy alone. We assessed each patient's eligibility for each AS criteria with and without the inclusion of fusion biopsy cores. The primary endpoint was the proportion of men who were initially eligible for AS but became ineligible after addition of the fusion biopsy cores. 100 men were eligible for at least one AS criteria. After addition of fusion biopsy cores, the proportion of men who became ineligible for AS varied from 10.3% to 40.7%. Criteria that incorporated an absolute maximum number of cores positive had the highest rates of ineligibility. Using a percentage of positive cores helped to reduce the number of patients who would have been excluded. Combining the targeted biopsy cores into one, or taking the single core with the highest grade or volume did not appear to reduce the proportion of men who became ineligible. The addition of fusion biopsy to standard 12-core biopsy significantly increased the number of men who became ineligible for AS. Using the percent of positive cores, instead of an absolute number, allowed fewer exclusions. AS criteria may need to be updated to prevent the unnecessary exclusion of men due to an oversampling of low-risk disease.