EURURO Vol. 71 No. 4

Introduction

Current guidelines recommend elective partial nephrec-

tomy (PN) as the standard surgical treatment for clinical T1a

renal tumors

[1,2]

and favor PN over radical nephrectomy

(RN) for T1b tumors when technically feasible

[1]

. For larger

(T2) renal tumors, RN is still regarded as the reference

standard, but emerging data suggest a potential role for PN

in select cases

[3] .

The most distinctive and attractive feature of PN over RN

relates to better renal functional preservation

[4] ,

whichmay

confer a lower risk of cardiovascular and metabolic sequelae

that would ultimately translate into better overall survival

[5]

. However, randomized control trial EORTC 30904 failed

to demonstrate a clear advantage in those terms in favor of

PN, despite demonstrating oncologic equivalence

[6] .

possible explanation for this finding is the recent identifica-

tion of different clinical impacts of medically versus

surgically induced chronic kidney disease (CKD)

[7]

Overall, the benefit of PN for larger masses (T1b and

above) is still under scrutiny, and the role of PN in this

setting requires better investigation

[8]

. Robust population-

based analyses of the Surveillance, Epidemiology, and End

Results (SEER) database have shown that PN for T1b tumors

provides cancer control equivalent to that of RN

[9,10] ,

but

PN use has remained limited in both Europe

[11]

and the

USA

[12]

. Emerging reports also suggest that among

patients with higher-risk masses (

7 cm), PN does not

compromise cancer-specific mortality

[12–19] .

In the context of this ongoing debate, only one systematic

review and meta-analysis, reported by Kim et al

[20]

2012, has so far evaluated the comparative effectiveness of

PN and RN for localized renal tumors. The authors included

36 studies involving more than 40 000 patients. They

considered all-cause mortality, cancer-specific mortality,

and the rate of severe CKD, and they reported an advantage

for PN. However, most of the studies included in their review

were on T1a tumors, for which the role of PN is already well

established. By contrast, there is no similar analysis in the

literature specifically for larger tumors (T1b and above).

With the aim of filling this gap, we designed the present

study to perform a meta-analysis of comparative functional,

oncologic, and perioperative outcomes for PN versus RN

specifically for larger renal masses (cT1b–2).

Evidence acquisition

2.1.

Search strategy

A systematic literature review was performed up to

December 2015 using multiple search engines (PubMed,

Ovid, and Scopus) to identify studies comparing PN to RN for

larger renal masses (clinical stage T1b).

Separate searches were carried out using both diagnosis

(renal mass, kidney cancer, renal tumor, 7 cm, 4 cm, T1b, T2)

and intervention terms (partial nephrectomy, radical

nephrectomy, nephron sparing surgery).

2.2.

Inclusion criteria, study eligibility, and data extraction

The Preferred Reporting Items for Systematic Reviews and

Meta-analysis (PRISMA) criteria were used for article

selection

( Fig. 1

), which was performed by two investigators

(M.C.M. and R.A.). The following study types were included:

original studies comparing PN to RN (regardless of the

technique) for larger renal masses, defined as such on the

basis of clinical stage (T1b and T2). All titles were screened

for manuscripts written in the English language, and only

on adult patients. The titles of the articles were first

reviewed to ascertain whether they might potentially fit

the inclusion criteria. After assessing the abstract, a more

thorough subsequent assessment was performed by looking

at the full text. Studies without primary data (ie, reviews,

commentaries, letters) were excluded but were examined to

ensure that relevant citations had been included. References

from the included studies were manually reviewed to

identify additional studies of interest. Disagreement on

whether or not an article should be included was resolved

using a third reviewer (H.Z.).

2.3.

Assessment of study quality

The level of evidence was rated for each study included

in the meta-analysis. The quality of each study was

for PN (WMD 107.6 ml;

0.001), as was the likelihood of complications (RR 2.0;

0.001). Both the recurrence rate (RR 0.61;

= 0.004) and cancer-specific mortality

(RR 0.65;

= 0.03) were lower for PN.

Conclusions:

PN is a viable treatment option for larger renal tumors, as it offers acceptable

surgical morbidity, equivalent cancer control, and better preservation of renal function,

with potential for better long-term survival. For T2 tumors, PN use should be more selective,

and specific patient and tumor factors should be considered. Further investigation, ideally

in a prospective randomized fashion, is warranted to better define the role of PN in this

challenging clinical scenario.

Patient summary:

We performed a cumulative analysis of the literature to determine the

best treatment option in cases of localized kidney tumor of higher clinical stage (T1b and T2,

as based on preoperative imaging). Our findings suggest that removing only the tumor and

saving the kidney might be an effective treatment modality in terms of cancer control, with

the advantage of preserving the kidney function. However, a higher risk of perioperative

complications should be taken into account when facing larger tumors (clinical stage T2)

with kidney-sparing surgery.

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