In the 201 men with a single positive SM, it was found in the apex in 75 men (37%), posterolateral in 70 men (35%), bladder neck in 20 men (10%), anterior in 25 men (12%), posterior in 11 men (5%), and in no men was a single positive SM found in the seminal vesicle. The positive SM rate decreased with time, from 18% in the early cohort versus 10% in the late cohort. Those with a positive SM had a 1.4 fold greater risk of progression than those with a negative SM (HR 1.39). In the multivariable analysis, significant differences were found between the effects of different sites of a positive SM on disease progression. A positive SM at the posterolateral or posterior regions significantly increased a patients’ risk of progression for a positive SM versus no SM at these sites. The authors attribute the posterolateral and posterior positive SM rates to neurovascular bundle preservation and an inherent risk of a nerve sparing operation.
This study out of Memorial Sloan Kettering reveals that there is a 40% increase in the recurrence rate of prostate cancer after surgery for a positive margin. The worst positive margins are in the area where the nerve bundles are.