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Health Outcomes Research

Assessing Performance Trends inLaparoscopic Nephrectomy and Nephron-sparing Surgery for Localized Renal TumorsMarc C. Smaldone, Alexander Kutikov, Brian Egleston, Jay Simhan, Daniel J. Canter,Ervin Teper, Rosalia Viterbo, David Y.T. Chen, Richard E. Greenberg, and Robert G. Uzzo

OBJECTIVE To assess the impact of laparoscopy on usage of partial nephrectomy (PN) by comparing nationalusage trends in patients undergoing surgery for localized renal tumors.

METHODS Using linked Surveillance, Epidemiology, and End Results (SEER)–Medicare data, we retrospec-tively examined trends in procedure usage from 1995 to 2007 for patients undergoing surgery forlocalized (stage I/II) renal masses. Procedures were classified as open radical nephrectomy(ORN), laparoscopic radical nephrectomy (LRN), open partial nephrectomy (OPN), and lapa-roscopic partial nephrectomy (LPN). Patients were further stratified by tumor size (�4 cm, �4–�7 cm, �7 cm). Data were primarily analyzed using logistic regressions.

ESULTS Patients (n � 11,689, mean age 74.4 � 5.7 years, 56% male) with a mean tumor size of 4.7 �3.3 cm met the inclusion criteria. From 1995 to 2007, ORN rates decreased and for each yearsuccessive year patients were more likely to be treated with OPN (odds ratio [OR] 1.17, 95%confidence interval [CI] 1.14-1.19), LRN (OR 1.44, CI 1.41-1.47), and LPN (OR 1.75, CI1.68-1.83). Although the increased usage of OPN (7.5% vs 13.6%, P � .001) and LPN (0% vs14.2%, P � .001) reached statistical significance, this was offset by a marked increase in LRNover the same time period (3.0% vs 43.0%, P � .001).

ONCLUSION Despite increasing emphasis on nephron preservation, PN usage rates remain low. Comparedwith a 40% increase in LRN, use of PN increased by only 20% from 1995 to 2007. As a result,72% of identified Medicare beneficiaries with localized tumors were managed with radicalnephrectomy (RN) in 2007. The trade-off of minimally invasive surgery for nephron preservation

may have adverse long-term consequences. UROLOGY 80: 286–292, 2012. © 2012 Elsevier Inc.

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In 2010, approximately 58,240 men and women werediagnosed with cancer of the kidney or renal pelvis(predominantly renal cell carcinoma [RCC]), and

13,040 (22.4%) will ultimately succumb to their disease.1

Because of increased use of cross-sectional abdominalimaging,2 a stage and size migration toward the detectionf smaller, clinically localized renal tumors has beenbserved resulting in an increased number of surgicalnterventions performed.3 Traditionally, clinical stage I

Financial Disclosure: The authors declare that they have no relevant financialinterests.Funding Support: This publication was supported in part by grant number P30CA006927 from the National Cancer Institute (to RGU). The content is solely theresponsibility of the authors and does not necessarily represent the official views of theNational Cancer Institute or the National Institutes of Health. The authors weresupported in part through the National Institutes of Health R03CA152388 (to BLE),and Department of Defense, physician Research Training Award (to AK).

From the Division of Urological Oncology, Department of Surgery, Fox ChaseCancer Center, Philadelphia, PA; and Department of Biostatistics & Bioinformatics,Fox Chase Cancer Center, Philadelphia, PA

Reprint requests: Robert G. Uzzo, M.D., Department of Surgery, Division ofUrologic Oncology, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA

e19111. E-mail: R_Uzzo@fccc.edu

Submitted: January 30, 2012, accepted (with revisions): February 28, 2012

286 © 2012 Elsevier Inc.All Rights Reserved

renal masses have been treated with surgical excision,most commonly by radical nephrectomy (RN). However,recent data has suggested that RN may predispose pa-tients to the sequelae of chronic kidney disease (CKD)when compared with PN (partial nephrectomy)4 withouta measurable cancer-specific survival benefit.5 This evi-dence has led national guidelines committees to recom-mend that nephron-sparing surgery (NSS) be consideredin all appropriate surgical candidates with a clinical T1renal mass presuming that adequate oncologic controlcan be achieved.6,7

Despite these recommendations, the adoption of PNhas been slow to gain traction,3 and a recent Surveil-ance, Epidemiology, and End Results (SEER) analysisrom 1999 to 2006 revealed that only 35% of patientsurgically managed for tumors �4 cm underwent NSS.8

The rapid diffusion of laparoscopic nephrectomy in com-munity urologic practice has been implicated in contrib-uting to the reduced usage of PN because of relativetechnical ease and low risk of morbidity.9,10 Using linked

EER-Medicare data from 1997 to 2002, Miller et al

legantly investigated trends in the use of PN and RN, as

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well as laparoscopy for patients undergoing renal surgeryand concluded that the surgery provided depended moreon individual surgeon practice style than on patient ordisease characteristics.11 Using a similar procedure iden-ification algorithm, our aim was to examine trends inenal surgery in a more contemporary SEER-Medicareohort (1995-2007) to further characterize use of laparo-copic nephrectomy and nephron-sparing techniques.

MATERIAL AND METHODS

The SEER program, as reported by the US National CancerInstitute, collects patient demographics and publishes incidenceand survival data from population-based cancer registries, cur-rently covering approximately 26% of the US population. Datafrom 1995 to 2007 from 17 SEER registries were abstracted.Among patients 65 years or older with a cancer diagnosisrecorded in the SEER data, 94% have been linked with Medi-care enrollment data.12

Study inclusion criteria included Medicare parts A and B ben-eficiaries for whom kidney cancer (�stage II, nonurothelial) wastheir first lifetime cancer diagnosis. For each identified case, wesearched both inpatient (Medicare Provider Analysis and Review[MEDPAR] file, based on International Classification of Diseases, 9thevision [ICD-9], Clinical Modification codes) and physician claimscarrier claims file, based on American Medical Association Cur-ent Procedural Terminology [CPT] and ICD-9 codes) for kidneyancer–specific diagnosis and procedural codes. All patients withn ICD-9 or CPT code indicating performance of surgery werencluded for analysis, whereas patients with missing procedure datand those with recurrent, advanced, or metastatic disease werexcluded.

National trends in procedure usage were determined from995 to 2007. Using physician and inpatient claims coding,ach surgical case was assigned to one of the following 4xclusive groups: (1) open radical nephrectomy (ORN); (2)pen partial nephrectomy (OPN); (3) laparoscopic radical ne-hrectomy (LRN); and (4) laparoscopic partial nephrectomyLPN). To account for lag between introduction of LRN andPN techniques and their respective CPT codes (2000, 2002),he proportion of laparoscopic cases before 2002 were estimatedased on an algorithm described by Miller et al incorporatingoth direct and indirect laparoscopy codes.13

Data AnalysesPatient characteristics were compared between procedure groupsusing analysis of variance and �2 tests. The Charlson comorbidityindex (CCI),14 modified for use with administrative claims data-ets,15,16 was calculated using physician, outpatient, and inpatient

hospital claims data. We restricted the study sample to subjectswho were �66 years at diagnosis to ensure that all subjects had �1year of claims data from which to derive comorbidity. Associationsbetween patient characteristics were assessed using multivariableregression analyses controlling for year treated. Estimates of pro-cedure usage over time were assessed using logistic regressionanalysis of the treatment received with year of diagnosis enteredvia restricted cubic splines, with 5 knots placed at empirical quan-tiles.17 Multinomial logistic regressions of surgery type with year ofiagnosis as the sole covariate were fit separately for each tumorize (ordinal variable: �4 cm, �4 – �7 cm, and �7 cm) to test

hether time trends in procedure use differed by tumor size group.

UROLOGY 80 (2), 2012

ll analyses were conducted using Stata version 10 (StataCorp,ollege Station, TX), with P values of � .05 considered statisti-

ally significant.

RESULTSBetween 1995 and 2007, 11,689 patients were identifiedwho met all inclusion criteria and had complete data.Mean age and CCI at the time of diagnosis were 74.4 �5.7 years (median 74, range 66-97) and 0.82 � 1.2(median 0, range 0-10), respectively, and review of de-mographic characteristics revealed a cohort of patientswho were predominantly male (56%), married (62%),and Caucasian (86%). Mean tumor size was 4.7 � 3.3 cm(median 4, range 0.1-9.9), of which 86% of identifiedmasses were categorized as stage I (�7 cm) at the time oftreatment (Table 1).

Patients were classified by procedure type: ORN (n �6542, 56%); OPN (n � 1580, 13%); LRN (n � 2886,25%); and LPN (n � 681, 6%) and usage rates weretrended by year of treatment received (Fig. 1). Treatmentgroups were similar with respect to race and Charlsonscore, whereas significant differences were observed inpatient age (P � .001), gender (P � .001), marriagestatus (P � .006), and geographic area of residence (P �.001). Comparing clinical characteristics, significant dif-ferences were observed with respect to tumor size (P �.001) and stage (P � .001) at the time of diagnosis (Table1). Controlling for year treated, age, CCI, gender, race,marital status, area of residence, and tumor size, patientswith increasing tumor size were less likely to undergoOPN (�4 – �7 cm, OR 0.23 [CI 0.20-0.27]; �7 cm, OR0.10 [CI 0.08-0.13]); LPN (�4 – �7 cm, OR 0.12 [CI0.09-0.16]; �7 cm, OR 0.04 [CI 0.02-0.07]); or LRN (�4– �7 cm, OR 0.81 [CI 0.73-0.90]; �7 cm OR 0.38 [CI0.33-0.45]) compared with patients undergoing ORN(Table 2). In addition, patients who were older at diagnosiswere less likely to undergo OPN (OR 0.96 [CI 0.95-0.97]),whereas patients from urban areas were more likely to un-dergo OPN (OR 1.39 [CI 1.18-1.65]), LPN (OR 1.59 [CI1.23-2.05]), or LRN (OR 1.32 [CI 1.15-1.51]) when com-pared with patients undergoing ORN. Additional observa-tions were that female patients were less likely to undergoOPN (OR 0.85 [CI 0.74-0.95], Hispanic patients were lesslikely to undergo LRN (OR 0.56 [CI 0.40-0.79]), and pa-tients with increasing CCI were less likely to undergo LPN(OR 0.90 [CI 0.84-0.97]).

Examining procedure usage over time, the rates ofORN decreased, whereas for each successive year patientswere more likely to be treated with OPN (OR 1.17, CI1.14-1.19), LRN (OR 1.44, CI 1.41-1.47), and LPN (OR1.75, CI 1.68-1.83). When stratified by tumor size (Fig.1), the increased usage of OPN and LPN was mostnotable for small (�4 cm) and intermediate (�4 – �7cm) tumors. The use of LRN significantly increased re-gardless of tumor size, and the decreased usage of ORNwas attenuated for larger tumors (Table 3). Comparing

usage trends between 1995 and 2007 for all tumors re-

287

n

Figure 1. Trends in usage from 1995 to 2007 of ORN, LRN, OPN, and LPN for the entire patient sample and stratified by tumorsize (�4 cm, �4 – �7 cm, and �7 cm). LPN performance trends from 1995 to 1999 are based on smoothed estimates and do

Table 1. Demographic and clinical data by procedure type

VariableAll Proceduresn � 11,689

ORNn � 6542

OPNn � 1580

LRNn � 2886

LPNn � 681 P Value

Mean � SD (median), N (column %)Age (y) 74.4 � 5.7 (74) 74.6 � 5.8 (74) 73.3 � 5.0 (73) 74.8 � 5.8 (74) 74.3 � 5.7 (74) �.001Gender �.001

Male 6552 (56.0) 3655 (55.9) 943 (59.7) 1547 (53.6) 407 (59.8)Female 5137 (44.0) 2887 (44.1) 637 (40.3) 1339 (46.4) 274 (40.2)

Marriage status .006Unmarried 4446 (38.0) 2527 (38.6) 548 (34.7) 1131 (39.2) 240 (35.2)Married 7243 (62.0) 4015 (61.4) 1,032 (65.3) 1755 (60.8) 441 (64.8)

Race .959Caucasian 10,045 (85.9) 5619 (85.9) 1,351 (85.5) 2481 (86.0) 594 (87.2)African American 922 (7.9) 513 (7.8) 128 (8.1) 231 (8.0) 50 (7.3)Asian/Hispanic/

Other722 (6.2) 410 (6.3) 101 (6.4) 174 (6.0) 37 (5.4)

CharlsonComorbidityIndex

0.82 � 1.2 (0) 0.80 � 1.2 (0) 0.85 � 1.2 (0) 0.86 � 1.2 (0) 0.80 � 1.1 (0) .1173

Tumor size (cm) 4.7 � 3.3 (4.0) 5.3 � 3.5 (4.5) 3.3 � 2.1 (2.9) 4.5 � 3.2 (4.0) 2.8 � 1.5 (2.5) �.001Clinical stage �.001

I (�7 cm) 10,059 (86.1) 5272 (80.6) 1521 (96.3) 2597 (90.0) 669 (98.2)II (�7 cm) 1630 (13.9) 1270 (19.4) 59 (3.7) 289 (10.0) 12 (1.8)

Area of residence �.001Rural 1817 (15.5) 1118 (17.1) 206 (13.0) 407 (14.1) 86 (12.6)Urban 9872 (84.5) 5424 (82.9) 1374 (87.0) 2479 (85.9) 595 (87.4)

ot represent the actual proportion of patients receiving LPNs in any given year. (Color version available online.)

288 UROLOGY 80 (2), 2012

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gardless of size, there was a marked reduction in numberof patients undergoing ORN (89.5% vs 29.2%, P �.001). However, although usage of OPN (7.5% vs 13.6%,P � .001) and LPN (0% vs 14.2%, P � .001) increasedignificantly over the time period, this was offset by aarked increase in LRN over the same time period (3.0%

s 43.0%, P � .001). For tumors �4 cm, although totalN usage rates increased from 1995 to 2007 (10.2% vs1.1%; P � .001), a similar trend was observed in theerformance of LRN (3.4% vs 36.7%; P � .001). As aesult, in our sample of Medicare beneficiaries with lo-alized disease, usage of nephron-sparing techniques in-reased by only 20% over the 10-year period, with 72% ofdentified patients still managed with RN in 2007.

COMMENTAfter the adoption of practice guidelines,6,7 performancef NSS for localized renal tumors has been proposed as auality of care indicator and has important implications

Table 2. Multinomial logistic regression analysis demonstrand type of procedure received

Characteristic

OPN

OR (CI) P Value

Year of diagnosis 1.18 (1.16-1.2) �.001Age (y) 0.96 (0.95-0.97) �.001CCI 0.98 (0.94-1.03) .517Gender

MaleFemale 0.84 (0.74-0.95) .007

RaceCaucasianAfrican American 1.01 (0.81-1.25) .953Other 0.96 (0.63-1.44) .831Asian 1.21 (0.80-1.83) .375Hispanic 0.81 (0.55-1.2) .292

Marriage statusUnmarriedMarried 1.06 (0.93-1.21) .376

Area of residenceRuralUrban 1.39 (1.18-1.65) �.001

Tumor size�4 cm�4 – �7 cm 0.23 (0.20-0.27) �.001�7 cm 0.10 (0.08-0.13) �.001

ORs indicate the increased odds of having the procedure relative

Table 3. ORs (95% CI) for year effect from multinomial logi�4 – �7 cm, and �7 cm)

Procedure:year effect

Tumor SizeP Value

Tu�4 cm �4

ORN 1.00OPN 1.21 (1.18-1.24) �.001 1.11LRN 1.45 (1.41-1.49) �.001 1.48LPN 1.83 (1.74-1.92) �.001 1.75

or the assessment of institutional case mix.18 However,

UROLOGY 80 (2), 2012

nitial efforts to characterize national practice patternsor the surgical management of the clinically localizedenal mass has revealed that nationwide usage of PN,lthough slowly increasing over time, remains an infre-uent occurrence.3,8,11,18 Consistent with these findings,erformance of PN in our sample of Medicare beneficia-ies rose only 20% over a 12-year period, reaching 28% in007. With heightened national attention to the risks ofKD associated with RN,4 further research is needed toetter understand why NSS remains underused. Similaro previous studies using SEER and the Nationwide In-atient Sample (NIS), our sample of Medicare beneficia-ies support that tumor size is most likely the primaryatient determinant of procedure type, whereas otherharacteristics such as patient age, comorbidity, gender,arital status, and geographic location can also be im-

licated.3,8,18

Although inequities in access to NSS have been dem-onstrated,19,20 provider reluctance is likely multifactorialin origin and is not determined strictly by patient or

associations between patients and clinical characteristics

LRN LPN

OR (CI) P Value OR (CI) P Value

(1.42-1.48) �.001 1.8 (1.72-1.88) �.001(1.00-1.01) .308 0.99 (0.98-1.01) .319(0.93-1.01) .180 0.90 (0.84-0.97) .006

(0.97-1.2) .149 0.81 (0.68-0.98) .029

(0.86-1.24) .743 1.01 (0.72-1.41) .945(0.78-1.5) .639 0.45 (0.21-0.97) .041(0.68-1.41) .906 1.33 (0.75-2.38) .330(0.40-0.79) .001 0.60 (0.32-1.12) .110

(0.92-1.14) .604 1.08 (0.89-1.31) .436

(1.15-1.51) �.001 1.59 (1.23-2.05) �.001

(0.73-0.90) �.001 0.12 (0.09-0.16) �.001(0.33-0.45) �.001 0.04 (0.02-0.07) �.001

RN.

regressions fit separately for stratified tumor size (�4 cm,

SizeP Value

Tumor SizeP Value7 cm �7 cm

OR (95% CI)0 1.007-1.16) �.001 0.99 (0.92-1.06) .6943-1.53) �.001 1.36 (1.29-1.43) �.0013-2.01) �.001 1.24 (1.01-1.52) .035

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rence, underappreciation of the impact of RN on renalfunction, and the increased risk of urologic complicationsas a result of the increased technical complexity ofNSS21,22 have all been attributed as contributing factorss well. What has been poorly characterized to date is thempact of the diffusion of laparoscopy in communityractice on nephron preservation. Introduced in early99123 and rapidly integrated in contemporary prac-

tice,24 LRN has been shown to have equivalent long-term oncologic outcomes, improved convalescence, andequivalent risk of morbidity when compared withORN.25,26

There is increasing concern that dissemination of LRNhas overtaken usage of NSS because of technical facilityand the perceived decreased risk of short-term postoper-ative morbidity.27 Consulting Ontario Cancer Registryecords from 1995 to 2004, Aboussaly et al demonstratedhat PN rates increased until 2003, then abruptly de-lined, a change that coincided with the introductionnd adoption of LRN.9 Although findings from a singleegional cancer registry cannot be extrapolated to esti-ate nationwide practice patterns, these data suggest

hat differential adoption of laparoscopy may contributeo this emerging quality-of-care issue. Using linkedEER-Medicare data from 1997 to 2002, Miller et alemonstrated that although PN rates increased, thereas a simultaneous rise in the use of LRN, an increase

hat was most pronounced in patients with tumors �4m.11 In our expanded sample of Medicare beneficiariesdentified over a 12-year period, the odds of undergoingPN increased by 17% per year (most notably for tumors4 cm), whereas the odds of undergoing LRN increased

y 44% per year over the same time period regardless ofumor size. Although a rapid increase in usage of LPNOR 1.75 [CI 1.68-1.83]) was observed over the sameime period, these odds ratios may be misleading becausef the small proportion of patients in our sample. Al-hough these trends demonstrate that NSS has demon-trably increased over time, it is still disheartening that in007, PN was performed in only 41% of Medicare ben-ficiaries with tumors �4 cm, whereas RN was performedn 59%.

It has been proposed that the breadth of availableechnology and ancillary health services present mayediate surgeon use of nephron-sparing or minimally

nvasive techniques.20 Although it is surprising that us-age of LRN continued to increase so dramatically overour study period, future investigations assessing the im-pact of current practice guidelines on contemporary prac-tice will be necessary because current SEER informationis available only through 2007. The use of NSS at tertiarycenters has risen dramatically over the past decade, andrecent institutional series report that up to 90% of pa-tients with a new diagnosis of a localized renal mass �4cm undergo NSS.28,29 Although population level analy-ses have not demonstrated such dramatic trends, urban

location, teaching hospital status, and high nephrectomy

290

volume have been associated with increased use ofPN.3,20 Since our sample was limited to cases diagnosedbetween 1995 and 2007, further investigation is neededto determine whether performance trends will supportfuture regionalization of patients with localized kidneytumors to higher-volume centers with substantial expe-rience in NSS.

Use of a patient sample comprised exclusively of Medi-care beneficiaries �66 years of age at the time of diag-nosis limits the generalizability of our results, which maynot be representative of the general population of pa-tients undergoing renal surgery for localized kidney can-cer.30 However, recent evidence has demonstrated thatinked SEER-Medicare claims may represent the mostccurate data source for ascertainment of population-ased patterns of surgical care, and a recent externalalidation of the claims algorithm used in this study tolassify the specific type of surgical therapy received re-orted a 98.3% agreement between data sources for clas-ification of PN vs RN and 97.5% for the open vs lapa-oscopic approach13 In addition, lack of clinical data,ncluding tumor anatomy, baseline renal function, andatient/surgeon preferences, affect the ability to deter-ine whether NSS or LRN is the most appropriate

reatment option on an individual basis. Furthermore,hronologic differences in the introduction of laparo-copic nephrectomy and increased emphasis on nephron-paring techniques affect the performance trends ob-erved in our study. Despite these limitations, we feel thatur study represents the most comprehensive contempo-ary analysis of trends in renal surgery performance toate, which has important implications for future quality-f-care assessment studies.

CONCLUSIONSRecent evidence suggests that NSS reduces the risk ofCKD and may affect survival in patients with localizedrenal tumors. Although rates of ORN have decreased by60% since 1995, there has been a 2-fold rise in the use ofLRN when compared with PN, and in 2007 72% ofpatients were still managed with RN. In patients present-ing with a clinically localized renal mass, the short-termbenefits of laparoscopy must be weighed against the long-term advantages of nephron preservation, even in thepresence of a normal contralateral kidney.

References1. Jemal A, Siegel R, Xu J, et al. Cancer statistics, 2010. CA Cancer

J Clin. 2010;60:277-300.2. Chow WH, Devesa SS, Warren JL, et al. Rising incidence of renal

cell cancer in the United States. Jama. 1999;281:1628-1631.3. Hollingsworth JM, Miller DC, Daignault S, et al. Rising incidence

of small renal masses: a need to reassess treatment effect. J NatlCancer Inst. 2006;98:1331-1334.

4. Huang WC, Levey AS, Serio AM, et al. Chronic kidney diseaseafter nephrectomy in patients with renal cortical tumours: a retro-spective cohort study. Lancet Oncol. 2006;7:735-740.

5. Van Poppel H, Da Pozzo L, Albrecht W, et al. A prospective,

randomised EORTC intergroup phase 3 study comparing the on-

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U

cologic outcome of elective nephron-sparing surgery and radicalnephrectomy for low-stage renal cell carcinoma. Eur Urol.2011;59:543-552.

6. Campbell SC, Novick AC, Belldegrun A, et al. Guideline formanagement of the clinical T1 renal mass. J Urol. 2009;182:1271-1279.

7. Ljungberg B, Cowan NC, Hanbury DC, et al. EAU guidelines onrenal cell carcinoma: the 2010 update. Eur Urol. 2010;58:398-406.

8. Dulabon LM, Lowrance WT, Russo P, et al. Trends in renal tumorsurgery delivery within the United States. Cancer. 2010;116:2316-2321.[PubMed].

9. Abouassaly R, Alibhai SM, Tomlinson G, et al. Unintended con-sequences of laparoscopic surgery on partial nephrectomy for kid-ney cancer. J Urol. 2010;183:467-472.

10. Miller DC, Taub DA, Dunn RL, et al. Laparoscopy for renal cellcarcinoma: diffusion versus regionalization? J Urol. 2006;176:1102-1106; [Discussion:1106-1107].

11. Miller DC, Saigal CS, Banerjee M, et al. Diffusion of surgicalinnovation among patients with kidney cancer. Cancer. 2008;112:1708-1717.

12. Giordano SH, Kuo YF, Duan Z, et al. Limits of observational datain determining outcomes from cancer therapy. Cancer. 2008;112:2456-2466.

13. Miller DC, Saigal CS, Warren JL, et al. External validation of aclaims-based algorithm for classifying kidney-cancer surgeries.BMC Health Serv Res. 2009;9:92-99.

14. Charlson ME, Pompei P, Ales KL, et al. A new method of classi-fying prognostic comorbidity in longitudinal studies: developmentand validation. J Chronic Dis. 1987;40:373-383.

15. Klabunde CN, Potosky AL, Legler JM, et al. Development of acomorbidity index using physician claims data. J Clin Epidemiol.2000;53:1258-1267.

16. Romano PS, Roos LL, Jollis JG. Adapting a clinical comorbidityindex for use with ICD-9-CM administrative data: differing per-spectives. J Clin Epidemiol. 1993;46:1075-1079; [Discussion:1081-1090].

17. Harrell FE Jr., ed. Regression Modeling Strategies: With Applications toLinear Models, Logistic Regression, and Survival Analysis. New York:Springer-Verlag; 2001.

18. Miller DC, Hollingsworth JM, Hafez KS, et al. Partial nephrectomyfor small renal masses: an emerging quality of care concern? J Urol.2006;175:853-857; [Discussion:858].

19. Hollenbeck BK, Taub DA, Miller DC, et al. National utilizationtrends of partial nephrectomy for renal cell carcinoma: a case ofunderutilization? Urology. 2006;67:254-259.

20. Miller DC, Daignault S, Wolf JS Jr., et al. Hospital characteristicsand use of innovative surgical therapies among patients with kid-ney cancer. Med Care. 2008;46:372-379.

21. Gill IS, Kavoussi LR, Lane BR, et al. Comparison of 1,800 laparo-scopic and open partial nephrectomies for single renal tumors.J Urol. 2007;178:41-46.

22. Simhan J, Smaldone MC, Tsai KJ, et al. Objective measures ofrenal mass anatomic complexity predict rates of major complica-tions following partial nephrectomy. Eur Urol. 2011;60:724-730.

23. Clayman RV, Kavoussi LR, Soper NJ, et al. Laparoscopic nephrec-tomy: initial case report. J Urol. 1991;146:278-282.[PubMed].

24. Morris DS, Miller DC, Hollingsworth JM, et al. Differential adop-tion of laparoscopy by treatment indication. J Urol. 2007;178:2109-2113; [Discussion:2113].

25. Tan HJ, Wolf JS Jr., Ye Z, et al. Population-level comparativeeffectiveness of laparoscopic versus open radical nephrectomy forpatients with kidney cancer. Cancer. 2011;117:4184-4193.

26. Wolf JS Jr., Merion RM, Leichtman AB, et al. Randomized con-trolled trial of hand-assisted laparoscopic versus open surgical livedonor nephrectomy. Transplantation. 2001;72:284-290.

27. Matin SF, Gill IS, Worley S, et al. Outcome of laparoscopic radicaland open partial nephrectomy for the sporadic 4 cm. or less renaltumor with a normal contralateral kidney. J Urol. 2002;168:1356-

1359; [Discussion:1359-1360]. t

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28. Thompson RH, Kaag M, Vickers A, et al. Contemporary use ofpartial nephrectomy at a tertiary care center in the United States.J Urol. 2009;181:993-997.

29. Zini L, Patard JJ, Capitanio U, et al. The use of partial nephrectomyin European tertiary care centers. Eur J Surg Oncol. 2009;35:636-642.

30. Cooper GS, Virnig B, Klabunde CN, et al. Use of SEER-Medicare data for measuring cancer surgery. Med Care.2002;40:IV-43-IV-48.

EDITORIAL COMMENTIt is well known that the treatment trends of localized kidneytumors have varied widely among tertiary care centers and thegeneral medical community for nearly a decade. Since the mid-to late 2000s, investigators from centers of excellence havereported usage rates of partial nephrectomy (PN) to be as highas 90% for pT1a tumors, whereas population-based studies, suchas those from the SEER cancer registry, have demonstrated ratesof �50% for similar sized tumors.1,2

The explanation for this disparity has been widely speculatedand is likely multifactorial. Putative factors include concernsover oncologic control of PN, lack of knowledge of the kidneyfunction benefits on nephron sparing, fear of surgery-relatedcomplications, as well as the technical challenges of PN. An-other factor, however, which has been suspected to be a deter-rent to the widespread use of PN, has been the adoption oflaparoscopy for the management of kidney tumors.3 Comparedwith open radical nephrectomy (ORN), laparoscopic radicalnephrectomy (LRN) has demonstrable benefits in perioperativeoutcomes, including decreased blood loss, less pain, shorterlength of stay, improved cosmesis, and faster return to work andnormal activities.4 Furthermore, from a technical standpoint,

RN is generally considered less demanding than PN, particu-arly laparoscopic PN (LPN), which is associated with uniquehallenges, including renorrhaphy as well as the time con-traints of renal ischemia.

The investigators in this study used the SEER Cancer Reg-stry linked to Medicare claims to assess the usage trends inRN as well as ORN, open partial nephrectomy (OPN), andPN for localized renal tumors treated between 1995 and 2007.he results of this interesting study demonstrate that although

here was a statistically significant increase in the usage of OPN7.5% vs 13.6%, P �.001) and LPN (0% vs 14.2%, P �.001)uring this time period, the substantial decline in the usage ofRN coincided with a dramatic increase in the usage of LRN

3% vs 43%, P �.001). What is most concerning, however, ishat such trends occurred for not only pT1b and pT2 tumors,ut also for pT1a tumors, which had been treated predomi-antly with PN at tertiary care centers by 2007. Although the

mpact of LRN on the usage of PN cannot be measured directlyrom this study, the results strongly support the notion that theidespread adoption of LRN by the general urologic commu-ity may be responsible in part for the disparity observed in these of PN observed at the end of the study period.Given the equivalent oncologic outcomes of PN vs RN, as

ell as the kidney functional advantages, it is imperative thatrologic surgeons recognize the potentially adverse downstreamffects of RN.5,6 Urologists, however, should also be remindedhat the benefits of LRN over ORN may be offset by the loss of

he entire kidney, particularly in patients with pT1a tumors.

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William C. Huang, M.D., NYU School of Medicine/NYUCancer Institute, New York, New York

References1. Sivarajan G, Huang W. Current practice patterns in the surgical

management of renal cancer in the United States. Urol Clin NorthAm. 2012;39:149-160 [PubMed].

2. Dulabon LM, Lowrance WT, Russo P, et al. Trends in renal tumorsurgery delivery within the United States. Cancer. 2010;116(10):2316-2321 [PubMed].

3. Abouassaly R, Alibhai SM, Tomlinson G, et al. Unintended con-sequences of laparoscopic surgery on partial nephrectomy for kidney

cancer. J Urol, Feb.;183(2):467-472.

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4. Dunn MD, Portis AJ, Shalhav AL, et al. Laparoscopic versus openradical nephrectomy: a 9-year experience. J Urol. 2000;164(4):1153-1159 [PubMed].

5. Huang WC, Levey AS, Serio AM, et al. Chronic kidney disease afternephrectomy in patients with renal cortical tumours: a retrospectivecohort study. Lancet Oncol. 2006;7(9):735-740 [PubMed].

6. Huang WC, Elkin EB, Levey AS, et al. Partial nephrectomy versusradical nephrectomy in patients with small renal tumors—is there adifference in mortality and cardiovascular outcomes? J Urol. 2009;181(1):55-61; [Discussion:61-52]. Epub 2008, 2013.

http://dx.doi.org/10.1016/j.urology.2012.02.069

UROLOGY 80: 291–292, 2012. © 2012 Elsevier Inc.

UROLOGY 80 (2), 2012