# Open Partial Nephrectomy in the Management of  Small Renal Masses

Authors: Ziya Kirkali; A. Erdem Canda
Journal: Advances in Urology
 (2008)

---

## Abstract

Introduction. Most of the kidney masses are being detected
incidentally with smaller size due to widespread use of imaging modalities leading
to increased RCC incidence worldwide with an earlier stage. This article reviews the
role of open partial nephrectomy (PN) in the management of small renal
masses. Material and Methods. Review of the English literature using
MEDLINE has been performed between 1963–2008 on small renal masses, partial
nephrectomy, kidney cancer, nephron sparing surgery (NSS), radical nephrectomy,
laparoscopy, and surgical management. Special emphasis was given on the indications
of NSS, oncological outcomes and comparison with open and laparoscopic
PN. Results. Overall 68 articles including 31 review papers, 35 human
clinical papers, 1 book chapter, and 1 animal research study were selected for the
purpose of this article and were reviewed by the authors. Conclusions. Currently,
open NSS still remains as the gold standard surgical treatment modality in patients
with small renal masses.


---

## Body

## 1. Introduction

Renal cell carcinoma (RCC) accounts for 3% of adult solid tumors; and the highest
incidence of RCC is detected between 50–70 years of age [1, 2]. Almost 20,000 renal cancer
patients are estimated to be detected yearly in the European Union [3]. In the pathogenesis of conventional RCC, mutations leading to
inactivation of the von Hippel Lindau (VHL) tumor
suppressor gene have been detected in the hereditary and up to 80% of sporadic
forms of clear cell RCC. Premalignant lesions in the kidney such as renal
intraepithelial neoplasia have been described, which seems to be sharing
similar genetical changes with RCC [4, 5]. Independent predictors of survival in
patients with RCC are limited. Tumor stage, grade, and patient-performance status
are the known prognostic indicators [6].Currently, most of the kidney
masses are being detected incidentally up to 40% with smaller size due to
widespread use of imaging modalities such as ultrasound (US), computed tomography (CT), and
magnetic resonance imaging (MRI). This leads to increased RCC incidence
worldwide [7] with an earlier stage which can be cured by surgery [8].This
paper reviews the role of open partial nephrectomy (PN) in the management of
small renal masses particularly focusing on indications, oncological outcomes
and comparison with laparoscopic PN.


## 2. Materials and Methods

Review
of the English literature using MEDLINE has been performed between 1963–2008 on
small renal masses, partial nephrectomy, kidney cancer, nephron sparing surgery,
radical nephrectomy, indications, outcomes, surgical management, and laparoscopy.Overall 68 articles including 31
review papers, 35 human clinical papers, 1-book chapter, and 1 animal research study
were selected for the purpose of this article and were reviewed by the authors.


## 3. Results and Discussion

Small renal masses are considered
as tumors less than 4 cm in size in the kidney although there is not an established consensus concerning a clear
cut-off value for the definition of a “small renal mass.” However, although 4 cm is commonly considered as the size limit for
nephron sparing surgery (NSS) in kidney tumors, when technically feasible, partial nephrectomy (PN) should
be performed irrespective of tumor size [9].


### 3.1. Radical Nephrectomy versus Partial Nephrectomy

Radical nephrectomy (RN) was first
described by Robson in 1963;
it has been the standard for the surgical treatment of kidney cancer [10]. Traditionally, RN can be regarded
as the optimal technique with long-term cancer control in kidney cancer [11]. Five-year cancer specific survival for patients
with organ-confined disease is over 90% after surgery alone. Since 15–25% of
incidentally detected tumours are benign, removing the whole kidney for a small
benign lesion is not logical [12]. Current indications of open RN can
be summarized as large tumor size which is not suitable for NSS or for
laparoscopy, locally advanced diseases, existence of complicated tumor thrombus
with vena cava extension, and presence of other concomitant diseases such as
renal artery stenosis or single-organ metastases necessitating open surgery [13].
Due to improved technology regarding radiologic imaging modalities and their
frequent use, currently most of the kidney tumors are detected incidentally
with smaller tumor size and are associated with less lymph node and adrenal
gland involvement [14]. Therefore, there is a tendency to perform NSS rather
than RN in suitable kidney tumors particularly with recent improvements in
surgical techniques.PN was first performed by Czerny in
1887 [15] and Vermooten described indications of conservative surgery in kidney
tumors in 1950 [16]. The goal of NSS is to preserve as much normal renal
parenchyma as possible and meticulous cancer control with negative surgical
margins and no local recurrence in the follow-up [17]. Multiple studies in the
last decade have established the safety and efficacy of PN for selected cases
with small renal tumors [11, 18, 19]. Such considerations have led to expanding
the indications of PN to include centrally located tumors and larger tumors up
to 7 cm [18, 19].


### 3.2. Indications of Open Partial Nephrectomy

The TNM 1997 classification considers tumor size of
4 cm as cut-off value in order to classify stage T1 tumors as T1a (≤4 cm) and
T1b (4–7 cm) [20]. Excellent
outcomes regarding tumors less than 4 cm in size treated with NSS have an
important impact in this staging. Current indications for open PN are
summarized on Table 1. In elective
setting when contralateral kidney is normal, NSS should be attempted whenever
feasible irrespective of the status of the contralateral kidney.Table 1
Open partial nephrectomy indications (table adapted from 12).
I. Absolute Indicationsa. Tumors in a solitary kidneyb. Bilateral synchronous renal massesc. Severe renal insufficiencyII. Relative Indicationsa. Presence of pre-existing renal disease in the
contralateral kidney1. Nephrolithiasis2. Recurrent pyelonephritis3. Mild-moderate renal insufficiency4. Ureteropelvic junction obstruction5. Vesicoureteral refluxb. Presence of diseases predisposing to renal
insufficiency1. Diabetes2. Hypertensionc. Patients with known multifocal disease or underlying
genetic syndromes1. Papillary RCC2. Von Hippel-Lindau disease


### 3.3. Surgical Technique and Complications

We
prefer a flank incision and a lumbar extraperitoneal approach. Kidney is
mobilized completely and explored for satellite lesions. If necessary,
intraoperative ultrasound can be used. Renal vessels are controlled by using
vascular clamps, vascular tape, or by the surgeon’s fingers. In difficult cases
the artery and the vein are clamped, and ice slush should be applied in order
to cool down the kidney. Scalpel, laser, ultrasonic aspirator, water jet,
cautery, blunt dissection, or combinations of these can be used to cut the
renal parenchyma in order to remove the tumor with surrounding few millimeters of
healthy parenchyma and together with the covering perirenal fat. In case of any
suspicion in terms of surgical margins, further resection can be performed. Frozen
section examination of the tumor bed is usually not helpful. Bleeders are
coagulated or sutured and collecting system is closed by absorbable sutures in
a water-tight manner if it has been opened. Peroperative hydration and diuresis
by mannitol infusion are
very helpful. Absorbable sutures for approximation of the renal parenchyma in a
‘‘suture of eight’’ or ‘‘Z’’ sutures fashion are useful. Perirenal fat or omentum can be used
in order to close the defect. A drain is placed in the retroperitoneum and
wound is closed. Because tumor cells might remain in the residual kidney after
resection, enucleation is usually discouraged (Figure1) [21].Figure 1
Techniques used in open NSS. NSS: Nephron sparing surgery.Renal
failure, post operative hemorrhage, urine leak, and urinary fistula are the
most frequently seen complications after open NSS [21, 22]. Recently, Van Poppel et al. compared the complications of elective open NSS surgery and RN for low-stage, incidentally
detected, solitary, small (≤5 cm) RCCs
in a prospective study in the presence of a normal contralateral kidney
(Table 2). They concluded that NSS
can be performed safely in this patient group with slightly higher complication
rates than after RN [23].Table 2
Complications of open NSS and RN [23].
NSS (%), (n=268)RN (%), (n=273)Rate of severe haemorrhage3.11.2Pleural damage11.59.3Spleen damage0.40.4Postoperative CT abnormalities5.82.0Urinary fistula development4.4—Reoperation for complications4.42.4Perioperative blood loss was slightly higher after RN
(P>.05).NSS: Nephron sparing surgery, RN: Radical
nephrectomy, CT: Computed tomography.


### 3.4. Outcomes of Open Partial Nephrectomy

Similar cancer-specific survival
rates and oncologic outcomes have been detected in patients with small
(<4 cm) renal masses who underwent RN or NSS. Therefore, currently NSS is
considered as the treatment of choice in these patients (T1a tumors) [9, 24–29] (Table 3).Table 3
Selected published series including patients
who underwent open NSS or RN for renal masses due to their tumor
size (table modified from [14]).
AuthorReferenceYearNLocal recurrence (%)5-year dfs (mos)Tumor size <4 cm in size*Hafez et al.[26]19993100.696Lee et al.[27]2000790100McKiernan et al.[24]20021171.2100Patard et al.[18]20043140.898Tumor size >4 cm in size**Hafez et al.[26]19991750.886Patard et al.[18]2004653.694Leibovich et al.[28]2004915.498Becker et al.[29]2006695.8100Selected series comparing outcomes of patients underwent NSS or RN for renal masses*RNNSSRNNSSRNNSSPatard et al.[18]2004107537999999798Lee et al.[27]2000183791001009696Leibovich et
al.[28]20048419198958698McKiernan et al.[24]20021731179996100100*Median
follow-up is >25 months for all studies.**Median follow-up is >47 months for all
studies.N: Number of patients, dfs: disease-free survival,
FU: Follow-up, mos: months.Ten-year oncological and functional
follow-up data revealed almost 100% survival, especially in patients with renal
tumors less than 4 cm in size [34–38] with PN. Therefore, open NSS is currently
accepted as the gold standard treatment modality for patients with small,
exophytic, easily resectable renal masses [19, 34]. In a series of 435 patients
who underwent NSS for a tumor size between 2.6–4.0 cm, local
recurrence was detected in 3 patients (0.7%) with a mean follow-up of 31–76 months, which
is ten times lower than the rate for NSS performed for an absolute indication [39].
Local recurrence has been reported to be between 0–12% in NSS which
is related with multifocal disease or insufficient resection of the tumor [40]. Local recurrence
is expected to be more frequent locally advanced disease [41].Presence
of preneoplastic lesions such as renal intraepithelial neoplasia in the
residual kidney might be a factor for the occurrence of local recurrence [4]. However, recurrence due to insufficient resection could be
prevented by proper surgical technique [42]. Multifocal tumors can be detected
both in large- and small-sized tumors [4].
Although there is a possibility of presence
of multifocality and premalignant lesions, local recurrence rate is quite low
in well selected cases after NSS [43].


### 3.5. Preoperative Kidney Biopsy

It has been demonstrated that almost a quarter of
all small renal masses (<4 cm) are benign lesions like
angiomyolipoma, oncocytoma, or metanephric adenoma. Preoperative
diagnosis of these lesions is difficult despite latest advances in imaging
techniques [27, 40, 44, 45]. Therefore, performing
RN would be unnecessary for these benign lesions. One may possibly think of
diagnosing these lesions preoperatively by kidney biopsy. Currently, the role
of renal biopsy in diagnosing these lesions is controversial. Although
preoperative fine needle aspiration biopsy can be performed for diagnosis, its
sensitivity is low, has complication risks such as bleeding and tumor seeding,
might give false positive and false negative results, and finally it needs an
experienced cytopathologist particularly subspecialized in kidney and RCC [17, 46]. We suggest kidney biopsy particularly in those
patients where renal lymphoma or metastatic involvement of the kidney is
suspected [47].


### 3.6. Optimal Margins in Open NSS and Significance of Performing Tumor Bed Biopsies

For tumors smaller than 4 cm, the
local/ipsilateral renal recurrence rate has been reported to range between 1.5 and
4% in open NSS series [34, 36]. In the past, a 1 cm normal parenchyma was suggested
as a safety margin in NSS but controversy exists concerning the optimal margin
width [48]. Intraoperative biopsy and frozen-section examination of the tumor
bed is suggested in order to rule out residual tumor in the kidney [49]. However,
false-positive and false-negative results can be obtained due to freezing artifacts and difficulty in distinguishing cancer cells from normal
cells [50] which might also lead to unnecessary resections or even RN [51]. It
has been shown that more than 30% of small renal tumors (≤4 cm) did not have an
intact pseudocapsule; and cancer cells might be detected beyond the
pseudocapsule reaching up to 0–5 mm [52]
therefore, an amount of normal kidney tissue surrounding the tumor is suggested
to be included with PN in order to prevent incomplete resection [53]. This
amount has been recommended to be at least 5 mm in NSS by some authors [52], whereas
others suggest a normal tissue safety margin of ≥1 mm to be removed [54]. In
conclusion, the margin status rather than size seems to be important in NSS and
1 mm of normal parenchyma around the tumor seems to be enough.It is known that RCC has a 1–5% recurrence
rate in the contralateral kidney particularly in surgical margin positive
patients and patients with multifocal tumors which support NSS in this patient
group [55, 56]. Several authors suggest intraoperative use of ultrasonography to
rule out multifocal disease, and to clearly define tumor extent [57, 58]. Coagulation
of the tumor bed in addition to biopsies is recommended when tumor enucleation
is performed [59].


### 3.7. Open versus Laparoscopic Partial Nephrectomy

In the recent years, laparoscopy
has gained popularity and emerged as an alternative to open PN in the treatment
of renal masses [58]. Technical advances have enabled laparoscopists to
duplicate the techniques used during open PN, including vascular control,
hemostasis, and repair of the pelvicalyceal system [58, 60]. Promising postoperative and intermediate-term
oncological outcomes have been reported with laparoscopic partial nephrectomy
(LPN) [57, 61, 62].Recently, Lane BR and Gill IS
reported their 5-year outcomes in LPN including 58 patients which are
comparable to those of open NSS. At a median follow-up of 5.7 years, no distant
recurrence and a single local recurrence (2.7%) were detected. Overall and cancer-specific survival was 86% and 100%,
respectively, at 5 years [62]. Moinzadeh et al. also reported oncological
results in 100 patients with a minimum follow-up of 3 years. Overall survival
was 86%, and a cancer-specific survival was 100% [61].Although LPN seems to be a
promising and attractive surgical approach in the management of renal masses,
there are still some problems for LPN. Bleeding and hemostasis, prolonged warm ischemia, longer
operative time, increased intraoperative and renal/urological major
complication rates are considered as current problems associated with LPN. Hemostasis
and ischemia time is
the most challenging steps in LPN [60]. Bleeding during LPN is an important
problem for the surgeon although improved surgical techniques and skills
together with the use of new hemostatic sealants such as fibrin
glue-coated collagen patch which contains purely human coagulation factor components can be
helpful in order to overcome this problem [63–65].There are several
studies investigating the impact of the warm ischemia time on renal functions
and as a widely accepted guideline for clinical practice, warm renal ischemia
period exceeding 30 minutes is not recommended [66]. Furthermore, it is technically very demanding and time consuming to
produce cold ischemia during laparoscopic surgery [66]. Preservation of maximum functional
kidney tissue is one of the goals in PN, however, longer warm ischemia times have been
reported with LPN [33] compared to open NSS [30, 37].The
operating time seems to be decreased for LPN in the most experienced centers [30] however the learning curve is not
short and technical feasibility of an operation does not always necessarily
mean that it can be performed in common practice. This is still a major issue
when health care costs to society are concerned [12].Significantly
increased major complication rates have been reported with LPN compared to open
NSS by experienced authors [30, 37, 67]. However, for peripherally located, small,
and exophytic renal masses, we expect these complications to be lower.The risk of tumor spillage is also
a theoretical problem in LPN [60]. However, tumor spillage has been reported at
port sites in patients undergoing laparoscopic nephrectomy and
nephroureterectomy due to tumor [68].Decreased analgesic requirement,
decreased hospital stay, shortened convalescence, and improved cosmetics are
considered as the main advantages of LPN. The length of stay for patients undergoing
LPN in large series from Europe [31, 32] is ranging from 6 to 9 days whereas the
average length of stay in the United
States
is between 2 and 4 days [30, 33]. Gill
et al. reported their results comparing open versus laparoscopic PN (Table 4) [30]. Characteristics of some selected
series of LPN are summarized on Table 5
[31–33].Table 4
Comparison of laparoscopic versus open PN in
patients with a solitary renal tumor of 7 cm or less in size (table
modified from [30]).
Laparoscopic PN (n=100)Open PN (n=100)PComplications:Major intraoperative5%0%.02Renal/urological11%2%.01Median surgical time (hours)33.9<.001Blood loss (mL)125250<.001Mean warm
ischemia time (minutes)27.87.5<.001Median analgesic requirement
(morphine sulfate equivalents, mg)20.2252.5<.001Hospital stay (days)25<.001Average
convalescence (weeks)46<.001Median preoperative serum creatinine (mg/dL)1.01.0.52Median
postoperative serum creatinine (mg/dL)1.11.2.65PN: Partial nephrectomy.Table 5
Comparison of selected published series
related with LPN. Min: Minutes.
AuthorsCrepel et al.Häcker et al.Haber et al.Reference[31][32][33]CenterMutlicenter studyElisabethinen hospitalCleveland
clinicFranceAustriaOhio, USAYear200720072006Number of patients9125>500Tumor size (cm)2.72.62.9RouteTransperitonealTransperitonealTransperitonealretroperitonealretroperitonealWarm
ischemia time (min)352932Mean operating time163
min212
minTransperitoneal:
3.5 hRetroperitoneal:
2.9 hComplication rate (%)17.6836
and 16Mean blood loss (mL)363177.4150
versus 100 and 231Transfusion rate (%)6.64Not
reportedHospital stay (days)9.18.3Transperitoneal: 2.9Retroperitoneal:
2.2LPN: Laparoscopic
partial nephrectomy.The
follow-up after LPN is shorter compared to open NSS concerning oncologic
outcomes. LPN has a long learning curve and requires high-level laparoscopic
skills and experience. Long-term data indicate that NSS is safe and
oncologically effective in small renal masses <4 cm in size. Until the
problems with LPN are overcome, high complication rates are lowered and longer
oncological follow-up data are available, open NSS will be the standard
treatment for the surgical management of kidney tumors [12].


## 3.1. Radical Nephrectomy versus Partial Nephrectomy

Radical nephrectomy (RN) was first
described by Robson in 1963;
it has been the standard for the surgical treatment of kidney cancer [10]. Traditionally, RN can be regarded
as the optimal technique with long-term cancer control in kidney cancer [11]. Five-year cancer specific survival for patients
with organ-confined disease is over 90% after surgery alone. Since 15–25% of
incidentally detected tumours are benign, removing the whole kidney for a small
benign lesion is not logical [12]. Current indications of open RN can
be summarized as large tumor size which is not suitable for NSS or for
laparoscopy, locally advanced diseases, existence of complicated tumor thrombus
with vena cava extension, and presence of other concomitant diseases such as
renal artery stenosis or single-organ metastases necessitating open surgery [13].
Due to improved technology regarding radiologic imaging modalities and their
frequent use, currently most of the kidney tumors are detected incidentally
with smaller tumor size and are associated with less lymph node and adrenal
gland involvement [14]. Therefore, there is a tendency to perform NSS rather
than RN in suitable kidney tumors particularly with recent improvements in
surgical techniques.PN was first performed by Czerny in
1887 [15] and Vermooten described indications of conservative surgery in kidney
tumors in 1950 [16]. The goal of NSS is to preserve as much normal renal
parenchyma as possible and meticulous cancer control with negative surgical
margins and no local recurrence in the follow-up [17]. Multiple studies in the
last decade have established the safety and efficacy of PN for selected cases
with small renal tumors [11, 18, 19]. Such considerations have led to expanding
the indications of PN to include centrally located tumors and larger tumors up
to 7 cm [18, 19].


## 3.2. Indications of Open Partial Nephrectomy

The TNM 1997 classification considers tumor size of
4 cm as cut-off value in order to classify stage T1 tumors as T1a (≤4 cm) and
T1b (4–7 cm) [20]. Excellent
outcomes regarding tumors less than 4 cm in size treated with NSS have an
important impact in this staging. Current indications for open PN are
summarized on Table 1. In elective
setting when contralateral kidney is normal, NSS should be attempted whenever
feasible irrespective of the status of the contralateral kidney.Table 1
Open partial nephrectomy indications (table adapted from 12).
I. Absolute Indicationsa. Tumors in a solitary kidneyb. Bilateral synchronous renal massesc. Severe renal insufficiencyII. Relative Indicationsa. Presence of pre-existing renal disease in the
contralateral kidney1. Nephrolithiasis2. Recurrent pyelonephritis3. Mild-moderate renal insufficiency4. Ureteropelvic junction obstruction5. Vesicoureteral refluxb. Presence of diseases predisposing to renal
insufficiency1. Diabetes2. Hypertensionc. Patients with known multifocal disease or underlying
genetic syndromes1. Papillary RCC2. Von Hippel-Lindau disease


## 3.3. Surgical Technique and Complications

We
prefer a flank incision and a lumbar extraperitoneal approach. Kidney is
mobilized completely and explored for satellite lesions. If necessary,
intraoperative ultrasound can be used. Renal vessels are controlled by using
vascular clamps, vascular tape, or by the surgeon’s fingers. In difficult cases
the artery and the vein are clamped, and ice slush should be applied in order
to cool down the kidney. Scalpel, laser, ultrasonic aspirator, water jet,
cautery, blunt dissection, or combinations of these can be used to cut the
renal parenchyma in order to remove the tumor with surrounding few millimeters of
healthy parenchyma and together with the covering perirenal fat. In case of any
suspicion in terms of surgical margins, further resection can be performed. Frozen
section examination of the tumor bed is usually not helpful. Bleeders are
coagulated or sutured and collecting system is closed by absorbable sutures in
a water-tight manner if it has been opened. Peroperative hydration and diuresis
by mannitol infusion are
very helpful. Absorbable sutures for approximation of the renal parenchyma in a
‘‘suture of eight’’ or ‘‘Z’’ sutures fashion are useful. Perirenal fat or omentum can be used
in order to close the defect. A drain is placed in the retroperitoneum and
wound is closed. Because tumor cells might remain in the residual kidney after
resection, enucleation is usually discouraged (Figure1) [21].Figure 1
Techniques used in open NSS. NSS: Nephron sparing surgery.Renal
failure, post operative hemorrhage, urine leak, and urinary fistula are the
most frequently seen complications after open NSS [21, 22]. Recently, Van Poppel et al. compared the complications of elective open NSS surgery and RN for low-stage, incidentally
detected, solitary, small (≤5 cm) RCCs
in a prospective study in the presence of a normal contralateral kidney
(Table 2). They concluded that NSS
can be performed safely in this patient group with slightly higher complication
rates than after RN [23].Table 2
Complications of open NSS and RN [23].
NSS (%), (n=268)RN (%), (n=273)Rate of severe haemorrhage3.11.2Pleural damage11.59.3Spleen damage0.40.4Postoperative CT abnormalities5.82.0Urinary fistula development4.4—Reoperation for complications4.42.4Perioperative blood loss was slightly higher after RN
(P>.05).NSS: Nephron sparing surgery, RN: Radical
nephrectomy, CT: Computed tomography.


## 3.4. Outcomes of Open Partial Nephrectomy

Similar cancer-specific survival
rates and oncologic outcomes have been detected in patients with small
(<4 cm) renal masses who underwent RN or NSS. Therefore, currently NSS is
considered as the treatment of choice in these patients (T1a tumors) [9, 24–29] (Table 3).Table 3
Selected published series including patients
who underwent open NSS or RN for renal masses due to their tumor
size (table modified from [14]).
AuthorReferenceYearNLocal recurrence (%)5-year dfs (mos)Tumor size <4 cm in size*Hafez et al.[26]19993100.696Lee et al.[27]2000790100McKiernan et al.[24]20021171.2100Patard et al.[18]20043140.898Tumor size >4 cm in size**Hafez et al.[26]19991750.886Patard et al.[18]2004653.694Leibovich et al.[28]2004915.498Becker et al.[29]2006695.8100Selected series comparing outcomes of patients underwent NSS or RN for renal masses*RNNSSRNNSSRNNSSPatard et al.[18]2004107537999999798Lee et al.[27]2000183791001009696Leibovich et
al.[28]20048419198958698McKiernan et al.[24]20021731179996100100*Median
follow-up is >25 months for all studies.**Median follow-up is >47 months for all
studies.N: Number of patients, dfs: disease-free survival,
FU: Follow-up, mos: months.Ten-year oncological and functional
follow-up data revealed almost 100% survival, especially in patients with renal
tumors less than 4 cm in size [34–38] with PN. Therefore, open NSS is currently
accepted as the gold standard treatment modality for patients with small,
exophytic, easily resectable renal masses [19, 34]. In a series of 435 patients
who underwent NSS for a tumor size between 2.6–4.0 cm, local
recurrence was detected in 3 patients (0.7%) with a mean follow-up of 31–76 months, which
is ten times lower than the rate for NSS performed for an absolute indication [39].
Local recurrence has been reported to be between 0–12% in NSS which
is related with multifocal disease or insufficient resection of the tumor [40]. Local recurrence
is expected to be more frequent locally advanced disease [41].Presence
of preneoplastic lesions such as renal intraepithelial neoplasia in the
residual kidney might be a factor for the occurrence of local recurrence [4]. However, recurrence due to insufficient resection could be
prevented by proper surgical technique [42]. Multifocal tumors can be detected
both in large- and small-sized tumors [4].
Although there is a possibility of presence
of multifocality and premalignant lesions, local recurrence rate is quite low
in well selected cases after NSS [43].


## 3.5. Preoperative Kidney Biopsy

It has been demonstrated that almost a quarter of
all small renal masses (<4 cm) are benign lesions like
angiomyolipoma, oncocytoma, or metanephric adenoma. Preoperative
diagnosis of these lesions is difficult despite latest advances in imaging
techniques [27, 40, 44, 45]. Therefore, performing
RN would be unnecessary for these benign lesions. One may possibly think of
diagnosing these lesions preoperatively by kidney biopsy. Currently, the role
of renal biopsy in diagnosing these lesions is controversial. Although
preoperative fine needle aspiration biopsy can be performed for diagnosis, its
sensitivity is low, has complication risks such as bleeding and tumor seeding,
might give false positive and false negative results, and finally it needs an
experienced cytopathologist particularly subspecialized in kidney and RCC [17, 46]. We suggest kidney biopsy particularly in those
patients where renal lymphoma or metastatic involvement of the kidney is
suspected [47].


## 3.6. Optimal Margins in Open NSS and Significance of Performing Tumor Bed Biopsies

For tumors smaller than 4 cm, the
local/ipsilateral renal recurrence rate has been reported to range between 1.5 and
4% in open NSS series [34, 36]. In the past, a 1 cm normal parenchyma was suggested
as a safety margin in NSS but controversy exists concerning the optimal margin
width [48]. Intraoperative biopsy and frozen-section examination of the tumor
bed is suggested in order to rule out residual tumor in the kidney [49]. However,
false-positive and false-negative results can be obtained due to freezing artifacts and difficulty in distinguishing cancer cells from normal
cells [50] which might also lead to unnecessary resections or even RN [51]. It
has been shown that more than 30% of small renal tumors (≤4 cm) did not have an
intact pseudocapsule; and cancer cells might be detected beyond the
pseudocapsule reaching up to 0–5 mm [52]
therefore, an amount of normal kidney tissue surrounding the tumor is suggested
to be included with PN in order to prevent incomplete resection [53]. This
amount has been recommended to be at least 5 mm in NSS by some authors [52], whereas
others suggest a normal tissue safety margin of ≥1 mm to be removed [54]. In
conclusion, the margin status rather than size seems to be important in NSS and
1 mm of normal parenchyma around the tumor seems to be enough.It is known that RCC has a 1–5% recurrence
rate in the contralateral kidney particularly in surgical margin positive
patients and patients with multifocal tumors which support NSS in this patient
group [55, 56]. Several authors suggest intraoperative use of ultrasonography to
rule out multifocal disease, and to clearly define tumor extent [57, 58]. Coagulation
of the tumor bed in addition to biopsies is recommended when tumor enucleation
is performed [59].


## 3.7. Open versus Laparoscopic Partial Nephrectomy

In the recent years, laparoscopy
has gained popularity and emerged as an alternative to open PN in the treatment
of renal masses [58]. Technical advances have enabled laparoscopists to
duplicate the techniques used during open PN, including vascular control,
hemostasis, and repair of the pelvicalyceal system [58, 60]. Promising postoperative and intermediate-term
oncological outcomes have been reported with laparoscopic partial nephrectomy
(LPN) [57, 61, 62].Recently, Lane BR and Gill IS
reported their 5-year outcomes in LPN including 58 patients which are
comparable to those of open NSS. At a median follow-up of 5.7 years, no distant
recurrence and a single local recurrence (2.7%) were detected. Overall and cancer-specific survival was 86% and 100%,
respectively, at 5 years [62]. Moinzadeh et al. also reported oncological
results in 100 patients with a minimum follow-up of 3 years. Overall survival
was 86%, and a cancer-specific survival was 100% [61].Although LPN seems to be a
promising and attractive surgical approach in the management of renal masses,
there are still some problems for LPN. Bleeding and hemostasis, prolonged warm ischemia, longer
operative time, increased intraoperative and renal/urological major
complication rates are considered as current problems associated with LPN. Hemostasis
and ischemia time is
the most challenging steps in LPN [60]. Bleeding during LPN is an important
problem for the surgeon although improved surgical techniques and skills
together with the use of new hemostatic sealants such as fibrin
glue-coated collagen patch which contains purely human coagulation factor components can be
helpful in order to overcome this problem [63–65].There are several
studies investigating the impact of the warm ischemia time on renal functions
and as a widely accepted guideline for clinical practice, warm renal ischemia
period exceeding 30 minutes is not recommended [66]. Furthermore, it is technically very demanding and time consuming to
produce cold ischemia during laparoscopic surgery [66]. Preservation of maximum functional
kidney tissue is one of the goals in PN, however, longer warm ischemia times have been
reported with LPN [33] compared to open NSS [30, 37].The
operating time seems to be decreased for LPN in the most experienced centers [30] however the learning curve is not
short and technical feasibility of an operation does not always necessarily
mean that it can be performed in common practice. This is still a major issue
when health care costs to society are concerned [12].Significantly
increased major complication rates have been reported with LPN compared to open
NSS by experienced authors [30, 37, 67]. However, for peripherally located, small,
and exophytic renal masses, we expect these complications to be lower.The risk of tumor spillage is also
a theoretical problem in LPN [60]. However, tumor spillage has been reported at
port sites in patients undergoing laparoscopic nephrectomy and
nephroureterectomy due to tumor [68].Decreased analgesic requirement,
decreased hospital stay, shortened convalescence, and improved cosmetics are
considered as the main advantages of LPN. The length of stay for patients undergoing
LPN in large series from Europe [31, 32] is ranging from 6 to 9 days whereas the
average length of stay in the United
States
is between 2 and 4 days [30, 33]. Gill
et al. reported their results comparing open versus laparoscopic PN (Table 4) [30]. Characteristics of some selected
series of LPN are summarized on Table 5
[31–33].Table 4
Comparison of laparoscopic versus open PN in
patients with a solitary renal tumor of 7 cm or less in size (table
modified from [30]).
Laparoscopic PN (n=100)Open PN (n=100)PComplications:Major intraoperative5%0%.02Renal/urological11%2%.01Median surgical time (hours)33.9<.001Blood loss (mL)125250<.001Mean warm
ischemia time (minutes)27.87.5<.001Median analgesic requirement
(morphine sulfate equivalents, mg)20.2252.5<.001Hospital stay (days)25<.001Average
convalescence (weeks)46<.001Median preoperative serum creatinine (mg/dL)1.01.0.52Median
postoperative serum creatinine (mg/dL)1.11.2.65PN: Partial nephrectomy.Table 5
Comparison of selected published series
related with LPN. Min: Minutes.
AuthorsCrepel et al.Häcker et al.Haber et al.Reference[31][32][33]CenterMutlicenter studyElisabethinen hospitalCleveland
clinicFranceAustriaOhio, USAYear200720072006Number of patients9125>500Tumor size (cm)2.72.62.9RouteTransperitonealTransperitonealTransperitonealretroperitonealretroperitonealWarm
ischemia time (min)352932Mean operating time163
min212
minTransperitoneal:
3.5 hRetroperitoneal:
2.9 hComplication rate (%)17.6836
and 16Mean blood loss (mL)363177.4150
versus 100 and 231Transfusion rate (%)6.64Not
reportedHospital stay (days)9.18.3Transperitoneal: 2.9Retroperitoneal:
2.2LPN: Laparoscopic
partial nephrectomy.The
follow-up after LPN is shorter compared to open NSS concerning oncologic
outcomes. LPN has a long learning curve and requires high-level laparoscopic
skills and experience. Long-term data indicate that NSS is safe and
oncologically effective in small renal masses <4 cm in size. Until the
problems with LPN are overcome, high complication rates are lowered and longer
oncological follow-up data are available, open NSS will be the standard
treatment for the surgical management of kidney tumors [12].


## 4. Conclusions

Due
to widespread use of radiologic imaging modalities, most of the kidney tumors
are being detected incidentally with smaller size and earlier stage. Similar
oncologic outcomes have been detected in patients with small (<4 cm) renal
masses who underwent RN or NSS. Currently, NSS is considered as the treatment
of choice in patients with
kidney tumors when technically feasible irrespective of tumor size. In last few years laparoscopy has
gained popularity and emerged as an alternative to open PN particularly in the
surgical management of small renal masses. However, complication rates are
higher and oncological follow-up data is shorter compared to open PN therefore,
NSS still remains as the gold standard surgical treatment modality in patients
with small renal masses.



---

*Source: 309760-2008-07-15.xml*