AUA 2011 - Has a minimally invasive approach become more important than nephron preservation in the management of the clinically localized renal mass? - Beyond the Abstract

WASHINGTON, DC  USA ( - Due to increased utilization of cross sectional abdominal imaging, a stage and size migration towards the detection of smaller, clinically localized renal tumors has been observed resulting in an increased number of surgical interventions performed.

Traditionally, clinical stage I renal masses have been treated with surgical excision, most commonly by radical nephrectomy. However, recent data has suggested that radical nephrectomy may predispose patients to the sequelae of chronic kidney disease when compared to partial nephrectomy without a measurable cancer specific survival benefit. Despite these observations, the adoption of partial nephrectomy has been slow to gain traction, which may be at least partially attributed to the preferential adoption of laparoscopic nephrectomy in community practice.

As clinicians, we have the responsibility to continually reassess practice patterns to ensure we are providing optimal care. The AUA guidelines for the management of localized renal masses highlight the importance of oncologic efficacy, nephron preservation, and the use of minimally invasive techniques when appropriate, but radical nephrectomy utilization rates for localized tumors remains alarmingly high. Using a previously described algorithm for procedure identification using a large, national, administrative dataset, we examined trends in open and laparoscopic renal surgery over the past decade to further characterize the impact of laparoscopy on utilization of nephron sparing techniques

Using linked SEER-Medicare data, we examined national trends in utilization of open radical nephrectomy (ORN), laparoscopic radical nephrectomy (LRN), open partial nephrectomy (OPN), and laparoscopic partial nephrectomy (LPN) in patients with localized (stage I/II) renal masses from 1995-2005. (Linked data was not available after 2005.) Associations between clinical and demographic characteristics were assessed using multivariable regression analyses controlling for year treated. Estimates of procedure utilization over time for all tumors and stratified by tumor size (<4cm, >4 to <7cm, and ≥7cm) were assessed using logistic regression analyses of the treatment received with year of diagnosis entered via restricted cubic splines with 5 knots placed at empirical quantiles.

We identified 6,716 patients (mean age 74.2±5.7 years, 53.4% male) who underwent surgery for clinically localized tumors (mean tumor size of 4.8±3.2cm). Comparing patients undergoing ORN, LRN, OPN, and LPN, groups were similar with respect to marriage status, race, and Charlson Co-morbidity Index, while significant differences were observed in patient age (p<0.001), gender (p=0.01), and geographic area of residence (p<0.001). Comparing clinical characteristics between procedure groups, significant differences were observed with respect to tumor size (p<0.001) and clinical stage (p<0.001) at time of diagnosis When evaluated over time, the rates of ORN decreased while for each year successive year, patients were more likely to be treated with OPN (OR 1.18, CI 1.14- 1.21), LRN (OR 1.44, CI 1.40-1.48) and LPN (OR 1.68, CI 1.56-1.81). When stratified by tumor size (<4cm, ≥4-<7cm, ≥7cm), the increased utilization of OPN was most notable for <4cm tumors, the use of LRN significantly increased regardless of tumor size, and the decreased utilization of ORN was attenuated for larger tumors Comparing utilization trends in 1995 and 2005, there was a marked reduction in number of patients undergoing ORN (86.7% vs. 36.4%, p<0.001). However, while the increased utilization of OPN (6.7% vs. 13.5%, p=0.001) and LPN (0.6% vs. 9.3%, p<0.001) reached statistical significance, this was offset by a marked increase in LRN over the same time period (6.1% vs. 40.8%, p<0.001). As a result, utilization of nephron sparing techniques increased by only 15.5% over the ten year period, with 77% of identified patients with localized tumors still managed with radical nephrectomy in 2005.

Recent evidence suggests that nephron sparing surgery reduces the risk of chronic kidney disease and may impact survival in patients with renal cell carcinoma. In our cohort of Medicare beneficiares, while rates of ORN for clinically localized renal masses have decreased by 50% since 1995 there has been a two-fold rise in the utilization of LRN when compared to partial nephrectomy. The trade off of minimally invasive surgery for nephron preservation may have adverse long term consequences, and this issue should be further investigated.


Authored and presented by Marc Smaldone, Alexander Kutikov, Brian Egleston, Daniel Canter, Ervin Teper, Rosalia Viterbo, David Chen, Richard Greenberg and Robert Uzzo at the American Urological Association (AUA) Annual Meeting - May 14 - 19, 2011 - Walter E. Washington Convention Center, Washington, DC USA



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