Does Second Review of Prostate Needle Biopsy Pathology Impact Radiation Therapy Management? A Tertiary Cancer Center Study

Abstract

Prostate cancer (PC) therapy options are determined by patient risk stratification, based on Gleason score (GS), PSA and clinical staging. Studies have reported GS interobserver variability between pathologists. It is unclear how these differences impact radiation oncology-related recommendations. We aim to determine the frequency of diagnostic discordance between outside pathologists (OP) and specialized urologic pathologists (UP), and impact on active surveillance (AS) or radiation (RT) recommendations. 208 second opinion needle prostate biopsy pathology reviews were performed by UP at our institution in 2016. Our cohort consisted of 154 cases after excluding those with inadequate specimens, lack of initial pathology report, metastatic disease, and history of local therapy. Number of cores involved and highest GS reported at our institution by UP were compared to those reported by OP. NCCN risk groups were determined for patients with available PSA and cT classification (n=130). Risk groups included low (LR), favorable intermediate (FIR), unfavorable intermediate (UIR) and high risk (HR). FIR >75 yo and all LR were considered candidates for AS. LR and FIR were eligible for EBRT or brachytherapy alone (BA). FIR and UIR were eligible for RT with short term androgen deprivation therapy (EBRT + ST-ADT) +/- brachytherapy boost (BB) for only UIR. HR was eligible for EBRT with long term ADT (LT-ADT) +/- BB. Prostate size and IPSS were available to determine BA/BB eligibility in 112 patients. The agreement of treatment options between institutions was tested by McNemar’s exact tests. Discrepancy in highest GS was noted in 25% of cases. 6/12 cases initially reported as negative for cancer were identified to have PC. 29% of cases with PC had changes in % positive cores. NCCN risk group changed based on UP review in 25% (n=32) of cases, upgrading 34% and downgrading 66% of these patients. After UP review, the following patients were not found suitable for initial eligible treatment: 7% initially eligible for AS, 9% for BA, 7% for EBRT, 18% for EBRT + ST-ADT, 24% for EBRT + ST-ADT +BB, 31% for RT + LT-ADT and 29% for EBRT + LT-ADT +BB. Based on UP review, 10 new patients out of the total cohort (8%) were eligible for AS, 5 (4%) for BA, 14 (11%) for EBRT, 12 (9%) for EBRT + ST-ADT, 7 (5%) for EBRT + ST-ADT+ BB and 2 (2%) for EBRT + LT-ADT. 8 (6%) became eligible for brachytherapy (6 for BA and 2 for EBRT + ST-ADT+BB), but found to be poor candidates based on IPSS or prostate size. There was a change in treatment eligibility for 25% of the entire cohort. McNemar’s exact test showed UP review significantly differed impacting eligibility for EBRT + LT ADT (p=0.02) and EBRT alone (p=0.03) but not eligibility for AS (p=0.09), BA (p=0.12), EBRT + ST-ADT (p=0.66) or EBRT + ST-ADT + BB (p=1.0). UP review of prostate biopsies impacts risk groups, modifying RT recommendations. Second pathology review by a UP should be strongly considered prior to final treatment decisions for PC patients.