CRTA Post-Doctoral Research Fellow, Urologic Oncology Branch, National Cancer In
Introduction: The influence of anatomic location of prostate cancer (PCa) on biochemical recurrence (BCR) after radical prostatectomy (RP) is an active area of research. Some evidence suggests that anterior lesions are more commonly associated with extra prostatic extension (EPE) due to lack of a distinct capsule in the anterior portion of the prostate, and are more prone to metastasize due to proximity of the Batson venous plexus. We sought to evaluate whether anterior index lesion location is associated with increased rates of EPE, BCR or lymph node invasion (LNI). Methods: Clinical, imaging, and histopathological data were retrospectively analyzed for patients with PCa who underwent MRI prior to RP between 2008 and 2022. Anterior lesion location, as well as zonal anatomy, was determined by an expert genitourinary radiologist. Correlation with EPE, LNI, and BCR were analyzed using Wilcoxon rank sum and chi-squared tests. BCR-free survival (RFS) was analyzed using Kaplan-Meier (KM) survival curves. Results: 662 RP patients were identified with median follow up of 19 months (IQR 11-35). Anterior lesions were not associated with an increased rate of MRI-detected EPE (p>0.995), pathology-confirmed EPE (p=0.119), LNI (p=0.059), or BCR (p=0.203) (Table 1). A sub-group analysis of anterior lesions by zonal anatomy revealed that transition zone (TZ) lesions were associated with higher rates of MRI-detected EPE than peripheral zone (PZ) lesions (25/144 [19.4%] vs 2/54 [3.7%], p=0.024) but not pathology-confirmed EPE (p=0.392), LNI (p=0.890), or BCR (p=0.525). Differences in RFS were not significant for anterior vs non-anterior lesions overall (p=0.27) or when zonally divided (p=0.11) (Figure 1). Conclusions: Anterior prostate lesions were not associated with increased rate of EPE, LNI, or difference in RFS, even when sub-stratifying lesions by zone. Thus, anterior vs non-anterior lesion location is unlikely to impact risk stratification or clinical decision making. SOURCE OF Funding: N/A
