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Keywords:

  • laparoscopic partial nephrectomy;
  • cryoablation;
  • solitary kidney;
  • small renal mass;
  • kidney cancer;
  • renal function

Abstract

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

Study Type – Therapy (cohort)

Level of Evidence 2b

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

Tumour in a solitary functioning kidney represents an absolute indication for nephron-sparing surgery whenever technically feasible. We report the longest follow-up data comparing laparoscopic partial nephrectomy and laparoscopic cryoablation in patients with solitary kidney with oncological follow-up to five years.

OBJECTIVES

• We compare perioperative, functional and intermediate-term oncological outcomes of laparoscopic partial nephrectomy (LPN) vs laparoscopic cryoablation (LCA) for small renal tumour in patients with a solitary kidney.

• A treatment algorithm is also proposed.

PATIENT AND METHODS

• Over a 10-year period (02/1998-09/2008), 78 patients with a small tumour in a functionally solitary kidney underwent LPN (n= 48) or LCA (n= 30).

• Baseline, perioperative, and follow-up data were collected prospectively and analyzed retrospectively.

RESULTS

• Demographic data were similar between the LPN and LCA groups. Tumours were somewhat larger (3.2 vs 2.6 cm) in the LPN group. LPN was associated with greater blood loss (391 vs 162 mL; P= 0.003), and trended towards more post-operative complications (22.9% vs 6.7%; P= 0.07).

• By 3 months post-operative, eGFR decreased by 14.5% and 7.3% after LPN and LCA, respectively (P= 0.02). Post-operative temporary dialysis was required after 3 LPN (6.2% vs 0%, P= 0.16).

• Median follow-up time for LPN and LCA was 42.7 and 60.2 months, respectively.

• Local recurrence was detected in 4 (13.3%) LCA patients only (P= 0.02).

• Overall survival was comparable between LPN and LCA at 3 and 5 years, respectively (P= 0.74). The LPN group had superior cancer-specific and recurrence-free survival at 3 and 5 years compared to the LCA group (P < 0.05, for all comparisons).

CONCLUSIONS

• Given adequate technical expertise, both LPN and LCA are viable nephron-sparing options for patients with tumour in a solitary kidney.

• Although LCA is technically easier and has superior functional outcomes, oncologic outcomes are superior after LPN.


Abbreviations
LPN

laparoscopic partial nephrectomy

LCA

laparoscopic cryoablation

eGFR

estimated glomerular filtration rate

MDRD

modification of diet in renal disease

BMI

body mass index

ASA

American society of anethesiologists

NSS

nephron sparing surgery

INTRODUCTION

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

Patients with a small renal mass in a solitary kidney represent a challenging population where tumour control with maximal nephron preservation is essential. Until recently, partial nephrectomy in an anatomical or functionally solitary kidney was managed by open surgery [1]. Minimally invasive nephron-sparing surgery such as laparoscopic partial nephrectomy (LPN) and energy-based probe ablation such as renal cryoablation have gained interest at select centers worldwide. LPN, by duplicating open partial nephrectomy principles, has emerged as a viable alternative to open surgery [2]. Laparoscopic cryoablation (LCA) offers the advantages of minimally invasive surgery and due to its in situ ablative nature, does not impose surgical ischemia on the solitary kidney. We compare perioperative, functional and oncological outcomes of LPN vs LCA for small renal tumour in patients with a solitary kidney.

MATERIALS AND METHODS

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

Between 02/1998 and 09/2008, 78 patients with tumour in a solitary kidney underwent either LPN (n= 48) or LCA (n= 30). All patients undergoing a planned LPN or LCA for a radiologically-suspicious enhancing mass 7 cm or less were included in this study (clinical stage T1). Patients that underwent LCA were unable to undergo percutaneous approach due to tumour location and proximity to bowel. Selection of minimally invasive surgical treatment in the individual patient was non-randomized and at the discretion of the surgeon.

Baseline, perioperative, and follow-up data were collected prospectively in a database approved by the Institutional Review Board. Pre-operative evaluation included medical history, physical examination, serum creatinine level and abdominal CT or magnetic resonance imaging.

LPN was performed using our standard technique as described previously [3]. In brief, en-bloc renal hilar clamping, sharp excision of the tumour, suture repair of the collecting system when necessary and hemostatic renorrhaphy, with or without a bolster were performed. In the last 18 LPN cases, our ‘early unclamping’ technique[4]was employed in order to reduce warm ischemia time. LCA with double freeze-thaw cycle was performed under real-time laparoscopic ultrasound guidance. Intra-operative core needle biopsies of the tumour were obtained immediately before cryoablation.

Complications were classified as intra-operative and post-operative. Intra-operative complications included significant injury to an adjacent organ, major vessel, ureter or pleura and conversion for vascular injury or hemorrhage (necessitating intervention or transfusion of ≥3 units of packed cells). Post-operative complications occurring within 1 month, and urological complications and mortality within 3 months of surgery were recorded. Urine leakage was defined as a drainage >50 cc daily for more than 1 week with fluid biochemistry compatible with urine.

Post-operative follow-up in patients undergoing LPN comprised abdominal CT or MR scanning at 6 months and yearly thereafter in patients with pathologically-confirmed renal cancer. In patients undergoing LCA, serial MRI scanning was performed at planned intervals (day 1; month 3, 6 and 12; yearly thereafter) and CT-guided percutaneous needle biopsy of the cryolesion at 6 months postoperatively. If radiographic imaging was not performed at our institution, reports were obtained directly from the referring physician. All patients underwent serum creatinine testing and chest x-ray at regular intervals post-operatively. All demographic and perioperative data were entered prospectively into our computerized database. Cancer recurrence and patient survival were determined by follow-up clinical history and radiographic findings. When such survival data were not available, telephone calls were made directly to the patient or family members.

Pre-operative and post-operative estimated glomerular filtration rates (eGFR) were calculated with the abbreviated Modification of Diet in Renal Disease (MDRD) equation (eGFR (mL/min/1.73m2) =[(140 − age in years) * weight in Kg]/(72*serum creatinine in mg/dL)). Variation and percent change in renal function after LPN or LCA was calculated based on preoperative and nadir serum creatinine, defined as the maximum measured value between 7 days and 90 days after surgery.

Data analysis was retrospective. Mean ± SD is used to summarize continuous variables. Frequencies and proportions are used to summarize categorical variables. Statistical comparisons of continuous variables were made using the student t-test. Statistical significance was assessed based on a 2-sided significance level of 0.05.

RESULTS

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

Demographic data and Tumour characteristics (Tables 1,2): There were no significant differences between the LPN and LCA groups with respect to mean patient age, body mass index (BMI), Charlson Co-morbidity Index, and American Society of Anesthesiologists (ASA) score. Tumour size was somewhat larger (3.2 vs 2.6 cm; P= 0.23) in the LPN group but did not reach a statistical significance. Prior ipsilateral kidney surgery was noted in 8 patients (26.7%) in the LCA group and none in the LPN group (P= 0.0003). Contralateral radical nephrectomy for renal cell carcinoma (RCC) was the most common reason for solitary kidney status in the LPN (62.5%) and LCA (83%) groups, respectively (P= 0.08).

Table 1.  Demographic data and tumour characteristics
 Laparoscopic Partial Nephrectomy (n= 48)Laparoscopic Renal Cryoablation (n= 30)P
Age (year)60.6 ± 13.760.9 ± 11.40.7
Male (%)25 (52.1)22 (73.3)0.06
Body mass index30.1 ± 6.231.5 ± 5.80.37
Charlson comorbidities index 1.7 ± 1.3 2.0 ± 10.41
ASA score 2.7 ± 0.5 2.7 ± 0.80.9
Comorbidities (%)
 Coronary artery disease 6 (12.5) 3 (12)0.95
 Hypertension20 (41.7)16 (64)0.07
 Diabetes 6 (12.5) 3 (12)0.95
 CRI13 (27.1)13 (50)0.07
Number of tumours4835
Tumour size (cm) 3.2 ± 1.33 2.6 ± 1.080.23
Pathological Tumour Stage (%)   
 pT1a38 (79)24 (80)0.93
 pT1b 9 (19) 6 (20)0.89
 pT2 1 (2) 0 (0)0.43
Right kidney (%)26 (54.2)14 (46.7)0.64
Ipsilateral renal surgery (%) 0 8 (26.7)0.0003
VHL (%) 0 3 (10)0.053
Hilar tumour (%) 5 (10.7) 2 (6.7)0.7
Central tumours (%)22 (46.8) 8 (26.7)0.096
Table 2.  Reasons for solitary kidney
 Laparoscopic Partial Nephrectomy (n= 48)Laparoscopic Renal Cryoablation (n= 30)P
RCC31 (64.5)25 (83.3)0.07
Atrophy 8 (16.7) 4 (13.3)0.76
Congenital absence 4 (8.3) 00.16
VHL 0 3 (10)0.053
Oncocytoma 2 (4.2) 00.26
Urinary Reflux 0 1 (3.3)1.0
Angiomyolipoma 1 (2.1) 01.0
Transplant Donor 1 (2.1) 01.0
Trauma 1 (2.1) 01.0

Perioperative outcomes (Table 3): LPN was associated with greater blood loss (391 vs 162 mL; P= 0.003) and a trend towards more transfusion requirements (17% vs 3%; P= 0.14). Mean warm ischemia time was 24 min in the LPN group; the ‘early unclamping’ technique was used in the last 18 LPN cases with a mean warm ischemia time of 14 min. No hilar clamping was necessary in the LCA group. Intra-operative complications (6% vs 3.5%; P= 0.23) and post-operative complications (22.9% vs 6.7%; P= 0.07) trended higher in the LPN group, but did not reach statistical significance. Conversion to open surgery was necessary in 4 LPN cases (hemorrhage-1, inability to locate the tumour-1, positive margin at frozen section-1, difficult suturing angle at the upper pole under the liver dome-1); no open conversion was reported in the LCA group (P= 0.28). Hospital stay was longer in the LPN group (4.6 vs 2.4 days; P= 0.0001).

Table 3.  Intraoperative and postoperative outcomes
 Laparoscopic partial nephrectomy (n= 48)Laparoscopic renal cryoablation (n= 30)P
Transperitoneal approach (%) 37 (77.1) 14 (46.7)0.008
Estimated blood loss (mL)391.3 ± 692.0162.4 ± 163.20.003
Transfusion (%)  8 (16.7)  1 (3.3)0.14
Warm ischemia time (min) 24.0 ± 12.9  0
Total operating time (min)227.7 ± 73.1197.4 ± 52.60.14
Hospital stay (days)  4.6 ± 2.9  2.4 ± 2.20.0001
Intra-operative complication (%)  4 (8.3)  1 (3.5)0.38
 Ureter injury (%)  1 (2.1)  00.43
 Hemorrhage (%)  3 (6.2)  11
 Open conversion (%)  4 (8.3)  00.28
Post-operative complication (%)  11 (22.9)  2 (6.7)0.07
 Urine leak (%)  2 (4.2)  00.5
 Pulmonary (%)  1 (2.1)  1 (3.3)1
 Hemorrhage (%)  4 (8.3)  00.16
 Myocardial infarction (%)  1 (2.1)  01
 Infection (%)  0  1 (3.3)0.4
 Thrombo-embolic (%)  3 (6.3)  00.28

Renal function outcomes (Table 4): LPN group had lower baseline serum creatinine (1.2 vs 1.5 mg/dL; P= 0.008) and higher baseline eGFR (61.6 vs 53.8; P= 0.05) compared to the LPN group. By 3 months after LPN and LCA, eGFR decreased by 21.4% and 11%, respectively (P= 0.02). Nineteen patients (39.5%) had a CKD upgrade of 1 stage or more in the LPN group compared to 4 (13.3%) in the LCA group (P= 0.01). Three (6.2%) patients required postoperative dialysis after LPN, 2 (4.1%) of whom became dialysis-dependent at 1 year from chronic functional deterioration, whereas none required dialysis after LCA.

Table 4.  Renal function outcomes
 Laparoscopic partial nephrectomy (n= 48)Laparoscopic renal cryoablation (n= 30)P
Serum Creatinine data   
 Pre operative SCr (mg/dL) 1.2 ± 0.3 1.5 ± 0.50.008
 Post operative nadir SCr (mg/dL) 1.7 ± 0.9 1.7 ± 0.60.9
 SCr increase (mg/dL) 0.4 ± 0.5 0.2 ± 0.30.04
 Post-operative increase in SCr (%)35.1 ± 42.014.4 ± 21.00.013
eGFR data   
 Pre operative eGFR (mL/min/1.73m2)61.6 ± 18.653.8 ± 19.00.055
 Post operative eGFR (mL/min/1.73m2)47.5 ± 18.447.5 ± 14.80.6
 eGFR decrease after surgery   (mL/min/1.73m2)14.5 ± 16.4 7.3 ± 12.20.02
 Percent eGFR decrease after surgery (%)21.4 ± 21.9 11.0 ± 16.10.018
Chronic Kidney Disease data   
 Pre operative CKD stage 2.5 ± 0.7 2.8 ± 0.80.06
 Post operative CKD stage 2.9 ± 0.7 2.9 ± 0.60.9
 CKD stage increase 0.5 ± 0.7 0.1 ± 0.50.023
 CKD: 1 stage upgrade16 (33.3%) 4 (13.3%)0.049
 CKD: 2 stage upgrade 3 (6.2%) 00.166
 Dialysis:   
  Temporary (%) 1 (2.1%) 00.432
  Permanent (%) 2 (4.2%) 00.263

Oncologic outcomes (Table 5): Prior contralateral nephrectomy for RCC was noted in 31 patients (64.5%) in the LPN group and 25 patients (83.3%) in the LCA group (P= 0.07). Mean follow-up was 42.7 months and 60.2 months in the LPN and LCA group, respectively (P= 0.06). Final pathology confirmed renal malignancy in 75% and 83% of tumours in the LPN and LCA groups, respectively (P= 0.57). Local recurrence was detected only in 4 LCA patients (13.3%) and none in the LPN group (P= 0.02). Overall survival was comparable amongst the groups at 3 and 5 years (93% vs 93%) and (93% vs 88%), respectively (P= 0.74) (Figs. 1 and 2). Cancer-specific in the LPN and LCA groups was 100% vs 93% at 3 years and 100% vs 92% at 5 years (Fig. 3). Recurrence-free survival was 100% vs 88% at 3 years, and 100% vs 86% at 5 years in the LPN and LCA groups, respectively (P < 0.05, for all comparisons) (Fig. 4).

Table 5.  Oncological outcomes
 Laparoscopic partial nephrectomy (n= 48)Laparoscopic renal cryoablation (n= 30)P
Follow-up (mos) 42.7 ± 30.860.2 ± 46.30.06
RCC histology (%) 36 (75)25 (83.3)0.57
 Clear Cell 3020 
 Papillary  4 2 
 Chromophobe  2 0 
 Unclassified RCC  0 3 
Benign conditions/Biopsy (%) 12 (25) 5 (16.7)0.39
 Oncocytoma  8 0 
 Angiomyolipoma  3 0 
 Cyst  1 0 
 Neg for Neoplasm  0 5 
Positive margins  2n/a
Local Recurrence (%)  0 4 (13.3)0.02
Metastasis (%)  1 (2.1) 4 (3.3)0.05
De novo new tumour (%)  0 6 (20)0.0023
Survival data   
 Overall survival 3, 5 and 7 years (%) 93, 93, 8693, 88, 820.74
 Cancer-specific survival 3, 5 and   7 years (%)100, 100, 10093, 88, 820.027
 Local recurrence free survival 3, 5   and 7 years (%)100, 100, 10092, 86, 860.05
 Disease-free survival 3, 5 and   7 years (%) 96, 96, 9678, 64, 430.0003
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Figure 1. Overall survival.

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Figure 2. Disease-free survival.

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Figure 3. Cancer-specific survival.

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Figure 4. Local recurrence.

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DISCUSSION

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

The presence of tumour in a solitary functioning kidney represents an absolute indication for nephron sparing surgery (NSS) whenever technically feasible. As such, partial nephrectomy has been promoted as the standard of care in all patients with tumour in a solitary kidney [1]. Minimally invasive techniques have transformed surgery and NSS is no different. A multi-institutional retrospective analysis compared outcomes of 1800 patients undergoing open and laparoscopic partial nephrectomy for clinical stage T1 tumour. Patients in the open group had larger tumours and higher surgical risk. Perioperatively, patients in the laparoscopic group had decreased blood loss, 10 min longer ischemia time (30 min vs 20 min), shorter hospital stay, and somewhat more hemorrhagic complications (4.2% vs 2%). Both groups had comparable renal functional outcomes at 3 months, and early oncologic outcomes at 3 years were equivalent [3].

The renal functional outcomes in patients with solitary kidney following NSS are even more critical. Huang et al. demonstrated that the prevalence of chronic kidney disease in patients undergoing nephrectomy is higher than previously thought, with 26% of patients with normal contralateral kidney and normal serum creatinine (1.4 mg/mL or less) had chronic kidney disease prior to nephrectomy [5]. The patient with a solitary kidney clearly represents a higher risk group. Experiences with OPN indicate that the risk of end stage renal disease requiring dialysis in this population is 3.7–4.5%[1,6,7]. In the past 5 years, experiences with LPN in the setting of a solitary kidney have been described [8,9]. Lane et al. directly compared 30 LPN and 169 OPN in solitary kidneys and found a greater portion of patients dialysis temporarily or permanently after LPN, suggesting OPN may be a more preferable approach these patients with high risk for chronic kidney disease [10].

Recently, we demonstrated that by using the early unclamping technique and despite performing LPN for more complex tumours, we reduced significantly postoperative complications in the recent years. In particular, post-operative bleeding was reduced by over 50% from 6.5% to 2.1% (P= 0.034), the warm ischemia time was cut in half (31.9 to 14.4 min, P < 0.0001) and achieved superior renal functional outcomes compared to the earlier years [11].

Cryoablation destroys tumour by rapid freeze-thaw cycles at temperatures below minus 20° C. In contrast to LPN which is excisional, LCA destroys tissue in situ. LPN is technically challenging, requiring time-sensitive intra-corporeal suturing under ischemia. Longer warm ischemia time has been independently associated with decreased post-operative GFR [10]. LCA offers the potential of preservation of renal function [12,13] and decreased morbidity [13,14]. Desai et al. retrospectively examined LPN and LCA; there was a higher incidence of postoperative complications (16.3% vs 2.2%) and more blood loss (211 vs 101 mL) in the LPN group [15]. With respect to hilar tumours, Hruby et al. demonstrated significantly less postoperative complications [16]. These studies are limited in oncologic follow-up due to the lack of or limited amount of histological confirmation of complete tumour ablation.

To our knowledge, we report the longest follow-up data comparing LPN and LCA in patients with a solitary kidney with oncologic follow-up to 5 years. In a recent report of open surgical cryoablation of small renal tumours in a solitary kidney with median follow-up of 43 months in 11 patients, 9 had no evidence of recurrence, 1 patient had an indeterminate area and 1 patient was lost to followup [17]. No complications were reported. More recently, we reported our experience with minimally invasive NSS in solitary kidneys with 2-year oncologic follow-up [18]. The present study expands upon this initial report.

As demonstrated in LCA of small renal masses in the presence of 2 kidneys, LCA in solitary kidneys showed significantly less blood loss vs LPN (162 mL vs 391 mL, P= 0.003), which can be attributed to the in situ nature of LCA. Hospital stay is significantly less in the LCA group (2.4 days vs 4.6 days, P= 0.0001). Intra-operative complication rates were not significantly different among groups. Post-operative complications trended toward significance with 22.9% in LPN vs 6.7% in LCA, including urine leak in 2 LPN patients compared to none in the LCA group. This underscores the natural healing of the collecting system without urinary leakage despite of cryoinjury (bar physical puncture with the cryoprobe) as demonstrated by Sung et al.[19]. Hemorrhage did not occur in any patients postoperatively after LCA, suggesting improved technique with perpendicular probe insertion and maintenance of a fixed position may play a pivotal role. Without hilar exposure and intra-corporeal suturing, LCA is technically easier than LPN as evidenced in the overall lower total operating time and significantly less blood loss.

Given the high risk for ESRD of a solitary kidney due to decreased GFR in patients undergoing nephrectomy despite normal sCr[5] and the higher occurrence of patients on dialysis after LPN vs OPN [10], we examined the role of LCA to maximize the preservation of renal function as demonstrated in the lab[12] and clinically [13] and then compared directly to the outcomes after LPN. While patients undergoing LCA had a significantly higher preoperative sCr than those that underwent LPN, the increase in sCr postoperatively was significantly higher (35.1% vs 14.4%, P= 0.013). Furthermore, this is reflected in the significant decrease in eGFR (21.4% vs 11.0%, P= 0.018). This data is consistent with Carvalhal et al., who reported no significant differences in preoperative, postoperative creatinine or estimated creatinine clearance at 20.6 months followup [20]. Two patients who underwent LPN were dialysis dependent at 1-year vs none that underwent LCA. These results suggest that LCA has superior functional outcomes.

Previous studies of LCA were limited in follow-up. Local recurrence rates ranged from 0-3.7% with median follow-up from 6-36 months [13–16,21–23]. At a median 60.2 months follow-up, we observed 4 cases of local recurrence in the LCA group vs 0 in the LPN group (P= 0.02). At 5-year, overall survival was comparable between groups at 93% and 88% for the LPN and LCA groups respectively (P= 0.74). Disease specific survival was significantly different between LPN and LCA at 100% and 88% respectively at 5-year (P= 0.027). Furthermore, disease free survival at 5-year was significantly worse in the LCA group (64% vs 96%, P= 0.0003). To our knowledge, this is the first report of 5-year survival rates in this high-risk population of patients with solitary kidneys, which expands upon our previous publication with 2-year follow-up [18].

Our intent was to look directly at laparoscopic approaches, understanding that percutaneous methods would certainly be safer, lead to earlier convalescence and be more cost-effective [24]. The patients included in this analysis were not candidates for percutaneous cryoablation due to the anterior location of the tumour and the proximity to bowel. Our 3-year local recurrence free rates in solitary kidney are similar to a recent study looking at percutaneous cryoablation of pT1NxMx renal masses (92% and 92.3%) [24]). These results are incongruence with previous data from Bandi et al. looking at small renal masses, demonstrating at 19 months of follow-up there was no difference in survival outcomes between laparoscopic and percutaneous cryoablation [25].

Limitations of the study include the retrospective, nonrandomized design.

In the absence of a study adequately powered to detect a small difference in overall survival in patients with tumour in a solitary kidney, we must balance advantages and drawbacks with respect to renal function and recurrence rate.

Based on our results, we propose a treatment algorithm for tumour in solitary kidney to aid the urologist in treatment selection (Fig. 5). This algorithm considers the mass suspicious for malignancy on imaging with increasing tumour size and/or the patient desire for active treatment and finally is not accessible for percutaneous probe ablation.

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Figure 5. Proposed treatment algorithm for tumour in solitary kidney based on level of pre-operative renal function.

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The proposed treatment algorithm is based mainly on baseline renal function and life-expectancy. This algorithm assumes availability of adequate laparoscopic expertise and infrastructure. Important additional considerations include tumour location, tumour size, and individual surgeon’s experience level. A limitation of this algorithm is that is based on the retrospective, nonrandomized design. Validation of such an algorithm is dependent prospective studies, which will need to be performed in the future.

CONCLUSION

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

Both LPN and LCA are viable nephron-sparing options for patients with a solitary kidney. LCA is technically easier and has superior functional outcomes. However, LPN has superior oncological outcomes. Longer data are needed to better define the role of LPN and LCA in this challenging patient population.

REFERENCES

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