MP33-20: Utility of additional targeted and systemic biopsies in the presence of an Index PI-RADS 5 lesion

Ahmad Alzubaidi*, Hershey, PA, Michael Maidaa, Gainesville, FL, Mohammad Said, Iowa City, IA, Grant Owens, Max Yudovich, Hershey, PA, R.Scott Grant, Camphill, PA, Thomas F. Stringer, Gainesville, FL, Chad Tracy, Iowa City, IA, Jay D. Raman, Hershey, PA

Introduction: Prostatic mpMRI targeted biopsy is increasingly utilized for the diagnosis of prostate cancer (CaP). Traditionally, systematic biopsy (SB) and targeted biopsies are performed for all index and non-index lesions. The diagnostic yield of additional biopsies is not clearly defined. We evaluate the utility of additional biopsies of non-index and SB in patients with a PI-RADS 5 index lesion to detect clinically significant cancer (CSC).

Methods: Records of 1029 patients undergoing transrectal mpMRI targeted biopsy across 4 medical centers were reviewed. Those with a PI-RADS 5 index lesion were included. Pathology obtained from the index PI-RADS 5 lesion was then compared to SB pathology, and that of the other PI-RADS lesions to evaluate for pathologic upgrade from benign or clinically insignificant cancer (CIC) to clinically significant cancer (CSC) (Grade Group=2).

Results: We identified 326 Index PI-RADS 5 lesions in patients. 191 (59%) targeted PI-RADS 5 biopsies had CSC, while 135 (41%) noted CIC or benign pathology. Figure summarizes pathologic findings in these respective subgroups. Of the 191 CSC lesions, SB further upgraded 40 patients (21%). Of the 135 CIC or benign lesions, SB upgraded 22 (16%) to CSC. 119 patients had =2 lesions; biopsy of non-index lesions showed an upgrade in only 15 (13%) patients, while 104 patients (87%) showed no change or downgraded Grade group.

Conclusions: When performing MRI targeted biopsy of an index PI-RADS 5 lesion, additional biopsies of non-index lesions offers minimal additional clinical value and could potentially be omitted. However, SB potentially identifies significant malignancies whereby 37% upgraded to CSC or higher Grade group.

Source of Funding: None