Objectives: To study the evolution of surgical margins in robotic prostatectomy (DVP), to ascertain the surgical volume necessary to provide quality cancer care.
Methods: Clinicopathologic data on consecutive DVP patients were abstracted from our institutional database. The primary outcome evaluated was the presence of any positive surgical margin. Surgeon DVP volume was the unit of exposure. A logistic model was fit to measure the association of volume and margin status, adjusting for patient differences.
Results: Between November 2001 and August 2005, 193 consecutive patients underwent DVP. Disease and patient characteristics were similar across the levels of surgeon volume. Overall, surgical margins did not dramatically decline over time (first 15 cases, 26% versus cases 81 and beyond, 22%; P = 0.82). However, extensive margins were largely eliminated (first 15 cases, 12% versus cases 81 and beyond, 2%; P = 0.05). After adjusting for preoperative patient differences, the odds of any positive margin among those treated by a surgeon in the highest-volume group was 0.99 (95% confidence interval 0.36 to 2.72) compared with those treated during a surgeon's first 15 cases.
Conclusions: Although extensive surgical margins decline with increasing volume, overall positive margin rates after DVP respond slowly. It seems that cumulative surgeon volume beyond that which can be obtained in the typical urology practice may be needed to obtain ideal margin rates with this new technology.