Impact of positive surgical margins after radical prostatectomy differs by disease risk group.

PURPOSE: Positive surgical margins have a negative impact on disease outcomes after radical prostatectomy, yet their prognostic value may vary depending on specific pathological characteristics. We examined the relationship of positive surgical margins to biochemical progression according to several clinicopathological features.
MATERIALS AND METHODS: We analyzed data from 1,268 patients who underwent radical prostatectomy for clinically localized prostate cancer at our center between 1992 and 2008, and did not receive any neoadjuvant or adjuvant treatment. We examined the relation of age, pretreatment prostate specific antigen, pathological T stage, radical prostatectomy Gleason score, disease risk group and surgical margin status to biochemical progression-free survival.
RESULTS: The overall positive surgical margin rate was 20.8% and median followup was 79 months. The impact of positive surgical margins was dependent on risk group. Biochemical progression-free survival was 99.6% for the negative surgical margin group vs 94.9% for the positive surgical margin group in low risk disease (log rank p = 0.53), 93.5% for the negative surgical margin group vs 83% for the positive surgical margin group in intermediate risk disease (log rank p <0.001) and 78.5% for the negative surgical margin group vs 57.1% for the positive surgical margin group in high risk disease (log rank p = 0.003). These differences remained significant in a multivariate Cox regression model adjusting for other clinicopathological features.
CONCLUSIONS: Positive surgical margins are an independent predictor of biochemical progression in patients with intermediate and high risk prostate cancer. Patients with low risk disease have a favorable long-term outcome regardless of margin status and may be candidates for expectant management even with positive surgical margins, sparing them the side effects and costs of treatment.