EURURO Vol. 71 No. 4

615 692

looked at PN outcomes among patients with large tumors
(pT2 or greater) or high-grade tumors, and found no
difference in cancer-specific mortality between PN and RN.
They concluded that the decision to perform PN should not
depend on the stage or grade, but rather on technical ability
to remove the tumor. Our cumulative analysis of the four
studies on T2 tumors available showed a higher recurrence
rate (RR 0.61; p = 0.004) and higher cancer-specific mortal-
ity (RR 0.65; p = 0.03) for RN. This can also be explained by
selection bias, as tumors were 2 cm larger among RN
patients. Nonetheless, these data suggest that PN may be
feasible for select T2 masses, and may provide acceptable
oncologic outcomes comparable to those for RN, while
conferring renal functional benefit.
Our study has a number of limitations. First, although
meta-analyses are a robust statistical tool, controversies
related to their inherent nature have been widely recog-
nized However, it has been argued that meta-analyses
should be performed within the frame of systematic
reviews to minimize biases , as is the case for our
study. Second, we did not take into account the ‘‘surgical
technique’’ factor, and we were not able to perform a
subgroup analysis based on surgical technique (open vs
laparoscopic vs robotic). Most of the available comparative
studies in our analysis were on open surgery, which
confirms that open PN remains the most widely utilized
gold standard technique for larger masses at present
. However, the PN landscape has witnessed a
paradigm shift over the last decade with the increasing
adoption of robot-assisted laparoscopy, which is becoming
the new standard for minimally invasive, nephron-sparing
surgery for small masses, with emerging data suggesting
feasibility for larger tumors Series from several
institutions have shown that robotic PN is feasible, safe,
and effective for clinical T1b and T2 tumors
. Third, it was not possible to stratify cases according
to histologic subtype. There was a higher rate of malignant
histology for the RN group on final pathology (RR 0.97;
p = 0.02), which can be regarded as another selection bias
factor. In addition, we could not estimate the impact of
specific tumor histology subtypes that are known to differ
in biology and aggressiveness, and may thus impact
outcomes between the two modalities .
4. Conclusions
Our systematic review and meta-analysis suggest that
despite the better perioperative morbidity offered by RN, PN
represents a viable treatment option for larger renal tumors
as it provides equivalent cancer control and better
preservation of renal function, with potential for better
long-term survival. PN use for T2 tumors should be more
selective, and patient and tumor factors should be taken
into consideration on a case-by-case basis. Our findings can
represent an important evidence-based counseling materi-
al, but should critically interpreted within the constraints
and limitations of this type of pooled analysis. Nevertheless,
our findings suggest that further investigation, ideally in a
prospective randomized fashion, is warranted to better
define the role of PN in the challenging clinical scenario of
larger renal masses.
This work was presented in part in abstract form at
the 2016 annual meeting of the American Urological
Association.
Author contributions: Riccardo Autorino had full access to all the data in
the study and takes responsibility for the integrity of the data and the
accuracy of the data analysis.
Study concept and design: Mir, Autorino, Derweesh.
Acquisition of data: Mir, Autorino.
Analysis and interpretation of data: Mir, Autorino, Derweesh.
Drafting of the manuscript: Mir, Autorino.
Critical revision of the manuscript for important intellectual content:
Porpiglia, Zargar, Derweesh, Mottrie.
Statistical analysis: Autorino.
Obtaining funding: None.
Administrative, technical, or material support: None.
Supervision: None.
Other: None.
Financial disclosures: Riccardo Autorino certifies that all conflicts of
interest, including specific financial interests and relationships and
affiliations relevant to the subject matter or materials discussed in the
manuscript (eg, employment/affiliation, grants or funding, consultan-
cies, honoraria, stock ownership or options, expert testimony, royalties,
or patents filed, received, or pending), are the following: None.
Funding/Support and role of the sponsor: None.
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