Analysis of Risk Factors Associated with Prostate Cancer Extension to the Surgical Margin and Pelvic Node Metastasis at Radical Prostatectomy

Abstract

We analyzed data from 107 consecutive patients with clinical stage B prostate cancer in an attempt to identify those at high risk for having involved margins or nodal metastasis. Each patient underwent transrectal ultrasound-guided sextant biopsies of the prostate. Patient age, surgical approach to prostatectomy, pre-biopsy prostate specific antigen (PSA) level, and number, location and maximum Gleason score of positive biopsies were statistically evaluated for all patients groups. Prostate volume and PSA density (PSAD) were calculated for all patients undergoing prostatectomy. Of the 101 patients who underwent radical prostatectomy 64 had negative margins, 37 had at least 1 positive margin and 11 of the 37 had more than 1 positive margin. Involved margins were most common at the apex (62%) and mid portion (59%) of the gland. Prostatectomy was not performed on 6 patients with nodal metastases evident on frozen section examination. Therefore, 43 patients are considered to be at high risk for having residual disease after surgery. The mean PSAD, PSA level and number of positive biopsies were significant (p < 0.05) predictors of tumor extension to the surgical margin. The mean number of positive biopsies, biopsy Gleason score and PSA level were significantly greater (p < 0.05) in patients with nodal metastases. Only 15% of the patients with a single positive biopsy had positive margins versus 47% of those with multiple positive biopsies (p < 0.05). Of the patients with tumor positive nodes on frozen section 67% had 5 or more positive biopsies, whereas only 9% of all others had that many positive biopsies (p < 0.05). The number of positive biopsy sites, PSAD and PSA level were significantly associated with tumor at the surgical margin or metastatic to the pelvic nodes.