EURURO Vol. 71 No. 4

614 692

Surgical morbidity is an important factor to consider
when comparing high-risk surgical procedures. We noted
lower estimated blood loss for RN (p < 0.001), although this
only amounted to approximately 100 ml, and is therefore
unlikely to be clinically significant. There was also a lower
likelihood of postoperative complications for RN (RR
1.74 overall; RR 2 for T2 tumors only), which is reflective
of the fact that PN is a more involved procedure than RN, as
it include all the steps for RN in addition to tumor resection
and renal reconstruction. Indeed, our findings mirror those
for EORTC 30904, which found higher incidence of
hemorrhage (3.1% vs 1.2%), urinary fistulae (4.4% vs 0%),
and reoperation (4.4% vs 2.4%) in those undergoing PN
. Indeed, the potential risk may be greater for larger and
more complex masses, for which more extensive parenchy-
ma resection and reconstruction are necessary. Thus, our
findings support a utility-based approach to patient
counseling whereby the potential benefits of PN must be
counterbalanced against the potential of higher surgical risk
and pre-existing patient comorbidity.
Consideration of the impact of renal functional preser-
vation is a cornerstone of comparison of RN and PN. A
decrease in renal function is associated with higher risk of
severe cardiovascular disease and all-cause mortality
Initial analyses suggested that RN might adversely
impact long-term survival when compared to PN in the
setting of larger masses . In a single-institution analysis
for the Cleveland Clinic, Weight et al studied about
1000 patients undergoing PN or RN for clinical T1b kidney
cancer, and they confirmed that postoperative renal
function was strongly associated with overall and cardio-
vascular survivals. Moreover, they estimated that the
average excess loss of renal function after RNwas correlated
with a 25% higher risk of cardiac death and 17% higher risk
of any-cause mortality . Recently published findings
from EORTC 30904 suggested that PN might reduce
moderate renal dysfunction (eGFR <60 ml/min), whereas
the incidence of severe CKD (eGFR <30 ml/min) and kidney
failure (eGFR <15 ml/min) is nearly identical between PN
and RN . In their meta-analysis of 34 comparative
studies, Kim et al calculated a cumulative 61%
reduction in the risk of severe CKD for those undergoing
PN, as well as a 19% risk reduction for all-cause mortality. In
our analysis specifically looking at clinical T1b and T2
tumors, PN was associated with better postoperative renal
function, as shown by higher postoperative eGFR (WMD
12.4 ml/min; p < 0.001), lower likelihood of onset of
postoperative eGFR < 60 ml/min (RR 0.36; p < 0.001), and
lower decline in eGFR (WMD –8.6; p < 0.001). Kopp et al
reported the only available comparative study for the
subset of T2 tumors, and noted a higher decline in eGFR for
RN patients (–19.7 vs –11.9 ml/min; p = 0.006) and a higher
rate of de novo CKD (40.2% vs 16.3%; p < 0.001). More
interestingly, the authors found that freedom from postop-
erative CKD was significantly higher for PN only in T2
patients with RENAL score 10. In other words, for more
complex masses the beneficial functional effect of PN over
RNmight disappear. These findings should be interpreted in
light of recent evidence supporting the concept that CKD ‘‘is
not created equal’’ . According to recently published
data, the annual decline in kidney function for patients with
preexisting CKD (CKD-M) compared to de novo CKD after
surgery (CKD-S) would be close to 5% versus 0.7%. Moreover,
the survival curves for patients with CKD-S approximate
survival curves for the overall population . Furthermore,
a recently published study on 4300 patients with median
follow-up of 9.4 yr demonstrated higher rates of progressive
decline in renal function, all-cause mortality, and non-renal
cancer mortality for CKD-M compared to CKD-S, whereas
CKD-S had survival approximating that for no CKD . The
study also affirmed the importance of renal functional
preservation by suggesting an association between post-
operative baseline eGFR of 45 ml/min and worse outcomes
following surgery.
Large and robust comparative oncologic data exist for
T1b renal masses. Early series demonstrated similar cancer-
specific mortality for PN and RN among patients with T1b
tumors (6.2% vs 9%; p = 0.6) A recent analysis of the
SEER database also demonstrated equivalent oncologic
outcomes in terms of cancer control when PN and RN were
compared at 10-yr follow-up . The authors analyzed
> 16 000 patients with pT1b tumors, adjusting the results
for competing-risk comorbidities. For a multicenter series
from Korea of 577 nephrectomies (110 PN; 477 RN) for T1b
tumors, Jang et al found similar cancer-specific survival
at 10 yr (85.7% for PN, 84.4% for RN; p = 0.52). Our findings
of a lower likelihood of tumor recurrence for PN (OR 0.6, 95%
CI 0.46–0.79; p < 0.001) and cancer-specific mortality (OR
0.58, 95% CI 0.41–0.81; p = 0.001), and all-cause mortality
(OR 0.67, 95% CI 0.51–0.88; p = 0.005) might be related to a
selection bias or to a protective effect of PN with regard to
risk of noncancerous (metabolic and cardiovascular)
adverse events.
Fewer comparisons exist for T2 tumors. Several single-
institutional data from centers of excellence suggest that PN
is equally effective from an oncologic standpoint. Karellas
et al analyzed 34 patients (median tumor size 7.5 cm),
mostly treated with elective indication, and found that PN
can be performed without major surgical complications and
with effective tumor control. This was confirmed by Long
et al, who reported a similar single-institutional study of
46 cases as well as a European study including
91 patients . By contrast, Peycelon et al suggested
that tumor size >7 cm (p = 0.002) is associated with poorer
oncologic outcomes, and Jeldres et al found a higher
risk of mortality for PN (HR 5.3; p = 0.025). However, both
studies were flawed by imbalanced sampling, with small
numbers in the PN arm, and therefore the findings should be
interpreted with caution. More reliable analyses have been
reported in studies comparing PN to RN for the specific
subgroup of T2 patients. Kopp et al found similar
oncologic outcomes for RN and PN, with a caveat that
outcomes were worse overall for tumors with a high RENAL
score (>10). In addition, they found better functional
preservation for PN, with nearly 2-yr loss in CKD-free
interval for RN compared to PN . Improved renal
functional outcomes for PN were also reported by Breau
et al . In a SEER database analysis, Hansen et al
E U R O P E A N U R O L O G Y 7 1 ( 2 0 1 7 ) 6 0 6 – 6 1 7 614