Significance of Prostatic Adenocarcinoma Perineural Invasion on Biopsy in Patients Who Are Otherwise Candidates for Active Surveillance.
Turki Alhussain, Jonathan I Epstein. The Johns Hopkins Hospital, Baltimore, MD
Background: The finding of perineural invasion on biopsy is associated with an increased of extra-prostatic extension at radical prostatectomy (RP). However, the significance of perineural invasion on biopsy in patients who otherwise meet biopsy criteria for active surveillance has not been studied.
Design: We utilized the most common biopsy criteria for active surveillance: 1) Gleason score ≤6; 2) ≤3 positive cores; and 3) ≤50% involvement any positive core. In addition, all cases had at least 12 biopsy cores (12-30), as this is also one of the criteria for our active surveillance program. We retrieved 313 cases which met the biopsy criteria for active surveillance, although men elected to undergo immediate RP at our institution between 1992 and 2008. These included 51 cases with perineural invasion and 262 cases without perineural invasion.
Results: Mean patient age was 58.2 years. There was no significant difference in patient age and mean serum PSA values in cases with perineural invasion and without perineural invasion, respectively). The maximum percentage of cancer per core per case was 40% (range 2-40% and mean 15.6%). Cases with perineural invasion on biopsy had a higher maximum percentage of cancer on biopsy (18.6%) vs. those w/o perineural invasion (15.0%), p=0.02. Cases with perineural invasion also had slightly more cases with 2 positive cores, compared to cases without perineural invasion (56.9% and 39.7% respectively, p=0.02). Despite a greater extent of cancer on biopsy, cases with and without perineural invasion on biopsy showed no significant difference in surgical margin involvement [3/50 (6%) vs. 19/262 (7.3%), respectively] or having organ confined disease [43/51 (84.3%) vs. 240/262 (91.6%), respectively]. In one case with perineural invasion the surgical margin was equivocal.
|Organ Confined||Margin (+)||RP GS > 6|
|PNI||43/51 (84.3%)||3/50 (6%)||13/51 (25.5%)|
|No PNI||240/262 (91.6%)||19/262 (7.3%)||54/259 (20.8%)|