Natural History of Biochemical Progression After Radical Prostatectomy Based on Length of a Positive Margin

Objectives: To assess the effect of length of positive margin on prognosis in men after radical prostatectomy. Methods: The positive surgical margin without either seminal vesicle invasion or lymph node metastases was identified in 117 men undergoing prostatectomy between 1991 and 1999. The length of positive margin was obtained by adding together the lengths of all areas of the tumor in contact with the inked surface. Biochemical failure was defined as a serum prostate specific antigen level 0.1 ng/mL or greater. Statistical analyses were performed to compare times with progression and to determine factors for progression. Results: The median follow-up duration was 43 months, and the overall 5-year progression-free survival (PFS) rate was 74.6%. The differences in prognoses between men with a positive margin 1 mm or less and those with a margin 1.1 to 3 mm was not significant; however, there was a significant difference in prognosis between men with a margin 3 or less and those with a margin greater than 3 mm (P <0.01). Multivariate analyses revealed that both Gleason score 8 or greater and a margin 3 mm or greater were independent predictors. The prognoses in men with neither of these risk factors was statistically better than that of men with either or both of these risk factors (5-year PFS rates 93% versus 57%, respectively; P <0.0001). Conclusions: The length of positive margin is significantly associated with disease progression. The Gleason score and the extent of positive margin can be used to stratify the risk for recurrence in patients with positive margin.