Comparison of Laparoscopic and Open Partial Nephrectomy. A retrospective review at the Massachusetts General Hospital
Audley L. Osbourne, MD, Ali K. Daha, MD, Christopher J. Cutie, MD, Dahl M. Dahl, MD, Adam S. Feldman, MD.
Massachusetts General Hospital, Boston, MA, USA.
BACKGROUND: Laparoscopic urologic surgeons have persistently challenged the gold standard with the hopes of providing improved outcomes in recovery and cancer treatment. Our study attempts to compare and contrast several variables with respect to laparoscopic vs. open partial nephrectomy for renal tumors.
METHODS: We reviewed data on 254 patients who underwent partial nephrectomy for Renal Cell Carcinoma (RCC) from November 1998 through March 2009. Individuals were separated into two cohorts, laparoscopic (LPN n=125) and open (OPN n=129). Individuals received open or laparoscopic surgery based on surgeon and patient preference and were not picked based on any particular clinical factor. We evaluated surgical margins in both groups taking note of any correlation with technique, tumor size, and stage. Patients were classified as having either T1 disease or T2 or greater.in an effort to simplify comparative analysis. We utilized student t-test, wilcoxon and pearson chi-square for statistical analysis.
RESULTS: Of the total open cases 87 patients (67.4%) were male, 42 patients (32.6%) female. Of the total laparoscopic cases 84 patients (67.2%) were male, 41 patients (32.8%) female. The mean age for OPN and LPN was 58.3 and 56.9 respectively showing no statistical difference in age make up between groups (p=0.18, t-test). The average tumor size for RCC in OPN and LPN was 2.99cm (range 1-16) and 2.35cm (range 0.5-7) respectively, illustrating a statistical difference (p=0.005, t-test). Average hospital stay for OPN patients was 4.6 days compared to 2.9 in the LPN group showing a statistical difference (p<0.001, t-test). Average surgical time for OPN was 3:35 compared to 3:55 for LPN. Of the OPN patients, 113 (87.60%) had T1 disease while 16 patients (12.4%) had T2 or greater. Of the LPN patients, 115 (92%) had T1 disease while 10 patients (8%) had T2 or greater showing no statistical difference between the two (p=0.25, pearson chi-square). 12 of 129 OPN patients (9.3%) and 5 of 125 LPN patients (4%) were found to have positive margins. Across both OPN and LPN, positive margin status correlated with size. Mean negative margin tumor size is 2.62cm, versus a mean positive margin tumor size of 3.37cm yielding a p-value of 0.0270 (Wilcoxon rank sums). When OPN and LPN groups are separated, margin status and tumor size bear no significant correlation.
CONCLUSIONS: Laparoscopic nephron sparing surgery is an efficacious minimally invasive alternative to the gold standard open approach for RCC. Our study has illustrated that a similar demographic of patients are being offered laparoscopic as well as open surgery for nephron sparing RCC surgery. Although there was a slight difference in tumor size between the lap and the open group, the challenge of obtaining negative margins in larger tumors seems to be independent of surgical approach. From a raw data standpoint, positive margin rate, surgical time, and hospital stay after LPN continue to stay low and or decrease, justifying it as a viable less invasive alternative to the traditional gold standard open method. We will likely need retrospective multicenter data in an effort to increase power and statistical significance.