SEARCH

SEARCH BY CITATION

Keywords:

  • kidney neoplasms;
  • health services;
  • diabetes mellitus;
  • hypertension

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

Study Type – Therapy (cohort)

Level of Evidence 2b

What’s known on the subject? and What does the study add?

We know that a major benefit of partial nephrectomy (PN) over radical nephrectomy (RN) is greater preservation of kidney function. Emerging evidence also suggests that chronic kidney disease (CKD) correlates with survival, likely as a result of increased cardiovascular morbidity. We also know that Diabetes Mellitus (DM) followed by Hypertension (HTN) are the two most frequent causes of end-stage renal disease (ESRD). Given the strong association between renal functional decline and the surgical treatment of small renal masses, one would expect utilization of PN in patients with HTN or DM to be high, however minimal data exist on PN use in these populations. We are thus unable to determine whether these patients are being managed optimally.

Our large study demonstrates that PN is being underutilized in patients at risk for CKD, particularly patients with Diabetes Mellitus and Hypertension. Unlike previously published reports, our population-level study provides a description of the landscape of care for patients with renal masses in general practice, and does not simply reflect treatment patterns at tertiary referral centers.

The finding of low PN use in patients at risk for CKD deserves further study. Future studies should focus on determining the specific factors contributing to PN underutilization in these susceptible patients, as well as developing clinical tools to reliably identify those patients in whom the benefits of PN outweigh the risks.

OBJECTIVE

  • • 
    To determine partial nephrectomy (PN) use in patients at risk of chronic kidney disease (CKD), such as those with diabetes mellitus (DM) and hypertension (HTN).

PATIENTS AND METHODS

  • • 
    We conducted a national, population-based, retrospective, observational study using the Canadian Institute for Health Information Discharge Abstract Database.
  • • 
    We included all patients treated surgically for renal cell carcinoma from 1 April 1998 to 31 March 2008.
  • • 
    Patients with DM and HTN were identified using specific diagnosis codes.
  • • 
    The proportions of patients treated with PN were compared in patients with and without DM and HTN using multivariable logistic regression adjusting for covariates.

RESULTS

  • • 
    A total of 24 579 patients were treated for a renal mass; of these, 4292 (17.5%) underwent PN.
  • • 
    In our sample, 5613 (22.8%) patients were identified as having HTN, and 2738 (11.1%) were identified as having DM.
  • • 
    PN was used in 17.3% of patients with HTN compared to 17.5% of those without HTN, whereas, in patients with DM, PN was used in 18.6% compared to 17.3% of patients without DM.
  • • 
    After adjusting for covariates, neither HTN, nor DM were found to be independently associated with increased PN use (odds ratio, 1.07; 95% CI, 0.98–1.16 and odds ratio, 1.08; 95% CI, 0.96–1.20, respectively).

CONCLUSIONS

  • • 
    In this contemporary national analysis, PN appears to be underutilized in DM and HTN, despite their known relationship with chronic renal failure.
  • • 
    Further studies are needed to elucidate the specific factors contributing to PN underutilization in these susceptible patients.

Abbreviations
CDI

Charlson Index

CIHI

Canadian Institute for Health Information

CKD

chronic kidney disease

DAD

Discharge Abstract Database

DM

diabetes mellitus

FSA

forward sortation area

HTN

hypertension

ICD

International Classification of Disease

OR

odds ratio

PN

partial nephrectomy

RN

radical nephrectomy

SEER

Surveillance, Epidemiology and End Results

INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

A major benefit of partial nephrectomy (PN) over radical nephrectomy (RN) is greater preservation of kidney function. Recent reports suggest that patients with T1a tumours are at significant risk of developing chronic kidney disease (CKD) after RN [1,2]. Emerging evidence also suggests that CKD correlates with survival, probably as a result of increased cardiovascular morbidity, with even mild reductions in estimated glomerular filtration rate [3–6]. Furthermore, recent studies have supplied preliminary evidence of an overall survival benefit with PN compared to RN [7–9].

Diabetes mellitus (DM) followed by hypertension (HTN) are the two most frequent causes of end-stage renal disease [10]. End-stage renal disease leads to significant morbidity and mortality and is a major burden to any healthcare system. Given the strong association between renal functional decline and the surgical treatment of small renal masses, one would expect the utilization of PN in patients with HTN or DM to be high; however, minimal data exist on PN use in these populations. A study using administrative data found that PN was used at a slightly higher rate in patients with HTN compared to those without (12.4% vs 9.9%) [11], although this was not the focus of the study, and therefore PN use in HTN was not examined in any detail. Data on PN use in patients with DM have not been published. We are thus unable to determine whether these patients are being managed optimally. The present study aimed to determine PN use in patients susceptible to CKD, specifically patients with HTN and DM.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

DATA

The present study comprised was a population-based, retrospective, observational study using administrative data. Data were obtained from the Canadian Institute for Health Information (CIHI) Discharge Abstract Database (DAD). The latter is a national database of all admissions to acute care institutions, and includes all Canadian provinces except Quebec [12]. Data for the present study included all acute inpatient records on patients treated by either RN or PN from 1 April 1998 to 31 March 2008. These were identified using specific procedure codes (see Appendix 1).

Demographic variables available from the CIHI DAD and analyzed in the present study include age, gender and forward sortation area (FSA; the first three digits of the postal code). Age was analyzed as both a continuous and a five-level categorical variable (<50, 50–59, 60–69, 70–79, ≥80). FSA was used as an ecologic proxy to estimate income quintile. Median individual income estimates were obtained for each FSA using Canadian 2006 census data and grouped into quintiles [13]. Additionally, given that the numbers of patients varied considerably between provinces, provinces were grouped into regions to allow adequate numbers for comparison. Provincial groupings were created for Atlantic (New Brunswick, Nova Scotia, Newfoundland and Prince Edward Island) and Prairie provinces (Alberta, Saskatchewan and Manitoba), whereas British Columbia and Ontario were analyzed independently. Using the total number of kidney procedures performed during the 10-year observation period, surgeon and hospital volume quartiles were also created for analysis.

CIHI permits a maximum of 25 diagnostic codes per hospitalization file in the DAD (comorbid conditions and complications). Specific diagnosis codes for DM (International Classification of Disease-9, ICD-9: 250.0–250.9 and ICD-10: E10–E14) and hypertension (ICD-9: 401.0–405.9 and ICD-10: I10–I15) were used to identify patients with these medical conditions. In the present study, adjustment of comorbidity was performed using the Deyo adaptation of the Charlson Index (CDI) [14,15], one of the most commonly used comorbidity measures for administrative data [14]. When analyses included the Charlson score as well as the presence of DM, a modified Charlson score excluding DM was used to avoid double-counting. Furthermore, as is standard for the CDI, patients were not scored for their primary diagnosis, which, in this case, was cancer of the kidney [16]. Ethics approval was obtained from the University of Toronto.

There were no missing data for fiscal year, age, gender or CDI category. Provincial region and income quintile were not available in 2 (8.2 × 10–5%) and 285 (1.2%) patients, respectively.

STUDY SAMPLE

The initial study sample included all discharge abstracts for patients treated by either RN or PN at an inpatient facility in one of the nine provinces supplying data to CIHI from 1 April 1998 to 31 March 2008. This represented information from 35 039 discharge abstracts. The dataset was restricted to patients aged ≥18 years (excluded 534 abstracts) given that indications for PN in paediatric tumours are not as well defined as in adult patients, and that the incidence of RCC in this age group is exceedingly low. Furthermore, only patients whose indication for surgery was a solid or cystic renal mass were included in the present study sample (i.e. tumours that could potentially be treated with PN). Other indications for nephrectomy, such as urothelial carcinoma, infection, polycystic kidney disease, non-function, etc., were not included because PN would not be offered to these patients (excluded 9926 abstracts). Thus, the final study sample included data on 24 579 discharge abstracts.

To assess more contemporary trends in PN use in susceptible patients, we performed a subset analysis on patients treated in the years 2006 and 2007 (5911 abstracts).

STATISTICAL ANALYSIS

The primary outcome of interest in the present study is PN utilization determined by specific procedure codes. The proportion of patients treated with PN was compared between those with and without DM using the chi-square test and an unadjusted logistic regression model. The same approach was used for HTN. Multivariable logistic regression models were also created with DM and HTN as independent variables, and adjusted for fiscal year category, age category, gender, provincial region, CDI score (excluding DM) and income quintile. Model discrimination and goodness-of-fit of the model were assessed using the concordance statistic and Hosmer–Lemeshow test, respectively.

In the contemporary subset (i.e. those treated in 2006 or 2007 only), the above analyses were repeated.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

A total of 24 579 patients were treated surgically for a renal mass between 1 April 1998 and 31 March 2008. Baseline characteristics of the patients are given in Table 1. Overall, 20 286 patients (82.5%) were treated with RN and 4292 patients (17.5%) were treated with PN. Descriptive statistics for patients treated with PN and RN are given in Table 2. No clear difference in gender or income is observed between the two groups; however, patients treated with PN appear to be younger, on average, than patients treated with RN.

Table 1.  Descriptive statistics on 24 579 discharge abstracts included in the present study
VariableValue
Fiscal year, n (%) 
 19982 048 (8.3)
 19992 187 (8.9)
 20002 267 (9.2)
 20012 255 (9.2)
 20022 246 (9.1)
 20032 384 (9.7)
 20042 583 (10.5)
 20052 698 (11.0)
 20062 875 (11.7)
 20073 036 (12.4)
Age 
 Mean (SD), years 61.4 (13.0)
 Median (IQR), years 62 (52–71)
 Range (years) 18–96
 <50, n (%)4 613 (18.8)
 50–59, n (%)5 885 (23.9)
 60–69, n (%)6 609 (26.9)
 70–79, n (%)5 852 (23.8)
 ≥80 (%)1 620 (6.6)
Gender, n (%) 
 Male14 769 (60.1)
 Female9 810 (39.9)
Provincial region, n (%) 
 Ontario12 394 (50.4)
 BC3 606 (14.7)
 Prairies5 218 (21.2)
 Atlantic3 359 (13.7)
Charlson category, n (%) 
 018 521 (75.4)
 13 635 (14.8)
 21 681 (6.8)
 ≥3742 (3.0)
Income quintile, n (%) 
 Q1: <$21 7584 877 (20.07)
 Q2: $21 758–24 4894 869 (20.04)
 Q3: $24 490–27 2294 844 (19.94)
 Q4: $27 230–30 4574 770 (19.63)
 Q5: ≥$30 4584 934 (20.31)
Physician volume quartile, n (%)
 Q1: ≤25 (1009 surgeons)6 185 (25.16)
 Q2: >25 to ≤47 (182 surgeons)6 254 (25.44)
 Q3: >47 to ≤95 (90 surgeons)6 064 (24.67)
 Q4: >95 (43 surgeons)6 076 (24.72)
Institution volume quartile, n (%) 
 Q1: ≤146 (145 hospitals)6 285 (25.57)
 Q2: >146 to ≤305 (27 hospitals)6 105 (24.84)
 Q3: >305 to ≤796 (13 hospitals)6 308 (25.66)
 Q4: >796 (six hospitals)5 881 (23.93)
Table 2.  Descriptive statistics for patients treated with partial nephrectomy (PN) and radical nephrectomy (RN)
VariablePN (n= 4292)RN (n= 20 286)
  1. IQR, interquartile range.

Age (years)  
 Mean (sd) 58.6 (13.1) 62.0 (12.9)
 Median (IQR) 60 (50–69) 63 (53–72)
 Range 18–93 18–96
Gender: male, n (%)2 553 (59.5)12 215 (60.2)
Median individual income ($)  
 Median (IQR)26 277 (22 806–30 033)25 772 (22 573–29 502)
Hypertension, n (%) 968 (22.6)4 645 (22.9)
Diabetes mellitus, n (%) 509 (11.9)2 228 (11.0)
Hypertension and diabetes mellitus, n (%) 238 (5.6)1 037 (5.1)
Charlson category, n (%)  
 03 322 (77.4)15 199 (74.9)
 1 612 (14.3)3 022 (14.9)
 2 234 (5.5)1 447 (7.1)
 ≥3 124 (2.9) 618 (3.1)

Using univariate logistic regression analyses, year of surgery, age category, provincial region, surgeon volume quartile, hospital volume quartile, Charlson category, and income quintile were all found to be associated with PN use, whereas gender was not. The odds ratio (OR) and 95% CI for all variables tested in a univariate logistic regression are given in Table 3.

Table 3.  Univariate logistic regression analyses assessing predictors of the use of partial nephrectomy
VariableUnivariate analyses
OR (95% CI)P
  1. OR, odds ratio.

Fiscal year category <0.001
 00–01 vs 98–991.25 (1.09–1.42) 
 02–03 vs 98–991.93 (1.70–2.19) 
 04–05 vs 98–992.12 (1.88–2.39) 
 06–07 vs 98–992.82 (2.51–3.16) 
Age category <0.001
 50–59 vs <500.79 (0.72–0.87) 
 60–59 vs <500.73 (0.66–0.80) 
 70–79 vs <500.60 (0.55–0.67) 
 ≥80 vs <500.29 (0.24–0.36) 
Gender (Female vs Male)1.03 (0.96–1.10)0.37
Hypertension (Yes vs No)0.98 (0.91–1.06)0.63
Diabetes mellitus (Yes vs No)1.09 (0.98–1.21)0.097
Charlson category 0.001
 1 vs 00.93 (0.84–1.02) 
 2 vs 00.74 (0.64–0.85) 
 ≥3 vs 00.92 (0.75–1.12) 
Income quintile <0.001
 Low vs Very low0.97 (0.87–1.08) 
 Intermed. vs Very low1.14 (1.03–1.27) 
 High vs Very low1.12 (1.01–1.25) 
 Very high vs Very low1.24 (1.12–1.38) 

PN USE AMONG PATIENTS WITH HYPERTENSION OR DIABETES

In the present study sample, 5613 patients (22.8%) were identified as having HTN, 2738 patients (11.1%) were identified as having DM and 1275 patients (5.2%) were identified as having both. Patients with HTN, DM, both, and neither, had mean Charlson scores (excluding DM) of 0.50, 0.50, 0.59 and 0.20, respectively. Patients with HTN were treated with PN in almost the same proportion as those without HTN (17.3% vs 17.5%, respectively; P= 0.63) (Fig. 1A). Patients with DM were treated with PN in a slightly higher proportion compared to patients without DM (18.6% vs 17.3%, respectively); however, this difference was not statistically significant (P= 0.097) (Fig. 1B). Patients with both HTN and DM were treated with PN 18.7% of the time, compared to 17.4% for patients with neither (P= 0.27). In a univariate logistic regression, the odds of having a PN did not significantly differ by the presence or absence of HTN (OR, 0.98; 95% CI, 0.91–1.06) or DM (OR, 1.09; 95% CI, 0.98–1.21). Furthermore, after adjusting for other covariates, neither HTN (OR, 1.07; 95% CI, 0.98–1.16), nor DM (OR, 1.08; 95% CI, 0.96–1.20) were found to be associated with PN use (Table 4). In the final model, fiscal year category, age category, provincial region, surgeon volume quartile, hospital volume quartile and Charlson category (excluding DM) were found to be associated with PN use, whereas gender, HTN, DM and income quintile were not. The model yielded a concordance statistic of 0.663, and model fit, as measured by the Hosmer–Lemeshow goodness-of-fit test, was adequate (P= 0.094).

image

Figure 1. Partial nephrectomy (PN) use by (A) hypertension (HTN) status and (B) diabetes mellitus (DM) status. RN, radical nephrectomy.

Download figure to PowerPoint

Table 4.  Multivariable logistic regression analysis assessing predictors of the use of partial nephrectomy
VariableMultivariable analysis*
OR (95% CI)P
  1. OR, odds ratio. *Multivariable analysis also adjusted for geographic region, surgeon volume quartile, and hospital volume quartile. C-statistic = 0.66, Hosmer–Lemeshow, P= 0.095.

Fiscal year category <0.001
 00–01 vs 98–991.16 (1.01–1.32) 
 02–03 vs 98–991.59 (1.39–1.81) 
 04–05 vs 98–991.71 (1.51–1.94) 
 06–07 vs 98–992.24 (1.98–2.53) 
Age category <0.001
 50–59 vs <500.77 (0.70–0.85) 
 60–59 vs <500.73 (0.66–0.80) 
 70–79 vs <500.62 (0.56–0.69) 
 ≥80 vs <500.31 (0.25–0.38) 
Gender (Female vs Male)1.05 (0.97–1.12)0.24
Hypertension (Yes vs No)1.07 (0.98–1.16)0.14
Diabetes mellitus (Yes vs No)1.08 (0.96–1.20)0.19
Charlson category (excluding diabetes mellitus) 0.001
 1 vs 00.91 (0.79–1.04) 
 2 vs 00.74 (0.64–0.87) 
 ≥3 vs 01.11 (0.85–1.43) 
Income quintile 0.46
 Low vs Very low0.98 (0.87–1.10) 
 Intermed. vs Very low1.04 (0.93–1.16) 
 High vs Very low1.02 (0.91–1.14) 
 Very high vs Very low1.08 (0.96–1.21) 

In the subset analysis of patients treated in 2006 or 2007 (1436 patients with PN; 24.3%), the results were unchanged compared to the entire cohort, and neither HTN, nor DM was associated with greater PN use (data not shown).

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

Overall, the present study showed low PN usage (17.5%) for the treatment of renal tumours in Canada. Fewer than one in five patients undergoing kidney surgery for a renal mass have their ipsilateral kidney preserved. This number is similar to other population-based studies examining PN utilization using either data from Surveillance, Epidemiology and End Results (SEER) [11,17,18] or the Nationwide Inpatient Sample [19]. These studies indicate an overall PN use of 7.5–11.1% in the USA [11,17,19] and data from SEER show that 35% of tumours ≤4 cm are treated with PN [18]. For these small tumours, many have suggested that PN usage in this range is too low, and that PN underutilization exists. Underutilization of PN is particularly troubling given the recent link established between renal function and overall survival [3]. Indeed, studies suggest that PN may offer a survival advantage over RN, even after adjusting for potential confounders, possibly as a result of renal functional preservation [7–9]. Recently published American Urological Association guidelines for the treatment of small renal masses suggest that PN be considered the reference standard for patients with T1a tumours, taking into account comorbidities and life expectancy [20].

The present study sample was found to have a 22.8% prevalence of HTN. This is similar to the 22.1% prevalence identified in a recent validation study assessing 4008 randomly selected hospital discharge records using specific ICD-10 diagnosis codes [21]. Compared to chart review, identifying the prevalence of HTN using hospital discharge administrative data yielded a positive predictive value of 79%, a negative predictive value of 92% and a kappa of 0.72 [21]. Similarly, in the present study, we would expect our definition of HTN to be highly specific, with a somewhat lower sensitivity. Therefore, patients labelled as having HTN are likely to have it and, as a result, a difference in PN use in this group probably would be detected in the present study.

Few data exist on the use of PN in patients with HTN. This is a result of comorbidity information not being available in SEER. However, one study identified patients with HTN using inpatient and physician Medicare claims that were submitted during the 12 months before the index admission for surgery of cancer of the kidney [11]. Linking these data to SEER, on univariate analysis, they found that patients with HTN were treated with PN 12.4% of the time compared to 9.9% in patients without HTN. The present study showed almost identical unadjusted PN use in patients with and without HTN (17.5% vs 17.3%, respectively). Even after adjusting for covariates, the odds of being treated with PN were not different between the two groups of patients (OR, 1.07; 95% CI, 0.98–1.16). Given the known link between HTN and CKD, the lack of increased PN use in this group is troubling.

In terms of DM, we found a prevalence of 11.1% in the dataset from the present study. Again, this is similar to the prevalence of 10.2% identified in the above-mentioned validation study [21]. Compared with HTN, the agreement with the chart data for DM was somewhat higher, with a positive predictive value of 0.82, a negative predictive value of 0.98 and a kappa of 0.79 [21]. The present study detected modestly higher PN use in patients with DM compared to patients without HTN (18.6% vs 17.3%, respectively); however, the adjusted odds of being treated with PN were not significantly associated with the presence of DM (OR, 1.08; 95% CI, 0.96–1.20).

The present study also investigated whether increased PN use in recent years has occurred given that long-term oncological efficacy data for elective PN has only been available since 1999 [22,23]. However, once again, we found no association between PN use and the presence of HTN and/or DM. This suggests that there is no trend of increased use in susceptible patients in recent years.

A potential reason for the underuse of PN in these susceptible patients may reflect the perceived increased morbidity of this procedure compared to RN, particularly in patients with potential sequelae of these comorbid conditions. On the other hand, we also know that the hazard ratio of death from all causes is strongly associated with renal function; ranging from 1.2 with an estimated GFR of 45–59 mL/min/1.73 m2 (95% CI, 1.1–1.2) to 5.9 with an estimated GFR of less than 15 mL/min/1.73 m2 (95% CI, 5.4–6.5) [3]. At the present time, the optimal balance between long-term renal functional preservation and increased short-term morbidity associated with PN is unknown. More research is needed to provide the surgeon with a clinical tool that can help weigh these factors, and determine the best treatment for a particular patient.

The most important limitation of the present study is the fact that tumour characteristics were not available for analysis. It is clear that tumour size, location and stage play an important role in treatment selection for RCC. However, at the present time, there are no data suggesting different tumour characteristics at presentation in susceptible patients (i.e. HTN and DM). Nonetheless, future population-based studies would be strengthened by the availability of tumour size and/or stage for analysis. The present study also lacks information on renal function and indications for treatment (i.e. elective vs imperative), which are factors that undoubtedly affect treatment selection in patients with renal masses. Another limitation of the present study is the fact that renal tumours treated with ablative therapies or active surveillance are not captured in the CIHI DAD, given that they are not performed in the inpatient setting. Although, during our observation period, we estimate that only a minority of patients were treated with active surveillance or ablative therapy, exact numbers on their use in Canada are currently not available. Additionally, comorbidity information in the CIHI DAD may be undercoded. Nonetheless, the CDI has been extensively validated in administrative data [24] and has been shown to correlate with operative mortality, complications and treatment choice [14,25–29]. Finally, a limitation of any study examining rates of PN use on a population level is that no consensus exists on the optimal proportion of renal tumours treated by this modality. What is known, however, is that almost half of all renal tumours treated at tertiary centres are treated by PN [30], although this may be more a reflection of referral patterns than the ideal PN use. Perhaps, in the future, a benchmark for PN use may be available to aid in the interpretation of studies such as the present one. However, what remains clear is that PN utilization overall is low, and is no greater in patients with HTN or DM.

The finding of low PN use in patients at risk for CKD deserves further study. These patients may benefit most from renal functional preservation. Future studies should focus on determining the specific factors contributing to PN underutilization in these susceptible patients, as well as aim to develop clinical tools to reliably identify those patients in whom the benefits of PN outweigh the risks.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

Appendix

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  9. Appendix

APPENDIX: RELEVANT PROCEDURE CODES (CCI and CCP)

Procedure descriptionCCI codesCCP code
  1. CCI, canadian classification of health interventions; CCP, canadian classification of diagnostic, therapeutic and surgical procedures.

Open radical nephrectomy1PC89LB6741
1PC89PF6472
1PC89QF6744
1PC91LB 
1PC91PF 
1PC91QF 
Laparoscopic radical nephrectomy1PC91DA 
 1PC89DA 
 1PC91AB 
Open partial nephrectomy1PC87LA673
 1PC87LAXXE
 1PC87LAXXG
 1PC87NQ
Laparoscopic partial nephrectomy1PC87DA