Preoperative prediction of surgical margin status in patients with prostate cancer treated by radical prostatectomy

Abstract

Purpose: We sought to determine the preoperative factors associated with surgical margin status in patients who underwent radical prostatectomy for prostate cancer.

Patients and methods: The study group consisted of 339 patients who were treated by radical retropubic prostatectomy and bilateral pelvic lymphadenectomy at the Mayo Clinic. None received preoperative adjuvant therapy. The mean age at the time of surgery was 66 years (range, 45 to 79 years). All specimens were totally embedded and whole-mounted. Positive surgical margin was defined as the presence of cancer cells at the inked margins. Numerous pathologic characteristics in needle biopsies and preoperative clinical findings were analyzed.

Results: The overall margin positivity rate was 24%. In univariate analysis, preoperative serum prostate-specific antigen (PSA) level, Gleason score, perineural invasion, percentage of cancer in the biopsy specimens, and number and percentage of biopsy cores involved by cancer were all associated with positive surgical margins. In multivariate analysis, preoperative serum PSA level (odds ratio for a doubling of PSA levels, 1.9; 95% confidence interval, 1.5 to 2.4; P <.001) and percentage of cancer in the biopsy specimens (odds ratio for a 10% increase, 1.3; 95% confidence interval, 1.2 to 1.4; P <.001) were predictive of margin status in radical prostatectomy. With use of preoperative serum PSA level and percentage of cancer in the biopsy as predictors of surgical margins, the overall accuracy as measured by the area under the receiver operating characteristic curve was 0.74.

Conclusion: Preoperative serum PSA level and percentage of cancer in the biopsy specimens were independently associated with surgical margin status in patients who underwent radical prostatectomy for prostate cancer. The combination of these two factors provides a high level of predictive accuracy for margin status.