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UROLOGICAL
ONCOLOGY
doi: 10.1590/S1677-55382011000200026
Simple
enucleation is equivalent to traditional partial nephrectomy for renal
cell carcinoma: results of a nonrandomized, retrospective, comparative
study
Minervini A, Ficarra V, Rocco F, Antonelli A, Bertini R, Carmignani G,
Cosciani Cunico S, Fontana D, Longo N, Martorana G, Mirone V, Morgia G,
Novara G, Roscigno M, Schiavina R, Serni S, Simeone C, Simonato A, Siracusano
S, Volpe A, Zattoni F, Zucchi A, Carini M
Members of the SATURN Project-LUNA Foundation University of Florence,
Florence, Italy
J Urol. 2011; 185: 1604-10
- Purpose:
The excision of the renal tumor with a substantial margin of healthy
parenchyma is considered the gold standard technique for partial nephrectomy.
However, simple enucleation showed excellent results in some retrospective
series. We compared the oncologic outcomes after standard partial nephrectomy
and simple enucleation.
Materials and Methods: We retrospectively analyzed 982 patients who
underwent standard partial nephrectomy and 537 who had simple enucleation
for localized renal cell carcinoma at 16 academic centers between 1997
and 2007. Local recurrence, cancer specific survival and progression-free
survival were the main outcomes of this study. The Kaplan-Meier method
was used to calculate survival functions and differences were assessed
with the log rank statistic. Univariable and multivariable Cox regression
models addressed progression-free survival and cancer specific survival.
Results: Median followup of the patients undergoing traditional partial
nephrectomy and simple enucleation was 51 ± 37.8 and 54.4 ±
36 months, respectively (p = 0.08). The 5 and 10-year progression-free
survival estimates were 88.9 and 82% after standard partial nephrectomy,
and 91.4% and 90.8% after simple enucleation (p = 0.09). The 5 and 10-year
cancer specific survival estimates were 93.9% and 91.6% after standard
partial nephrectomy, and 94.3% and 93.2% after simple enucleation (p
= 0.94). On multivariable analysis the adopted nephron sparing surgery
technique was not an independent predictor of progression-free survival
(HR 0.8, p = 0.55) and cancer specific survival (HR 0.7, p = 0.53) when
adjusted for the effect of the other covariates.
Conclusions: To our knowledge this is the first multicenter, comparative
study showing oncologic equivalence of standard partial nephrectomy
and simple enucleation.
- Editorial
Comment
In this pioneering study, it is fundamental to emphasize important information
regarding the limits of renal tumor simple enucleation – that
could be the message for those meticulous readers with a less optimistic
view.
The major point here is about the dubious clinical significance of simple
enucleation in terms of less morbidity while it comes with the cost
of worse cancer-specific survival, for Fuhrman grade 4 diseases, even
with the enucleation group biased for lessen high grade tumors in this
study, clearly showing that an additional margin of peri-tumor healthy
renal parenchyma is necessary for high grade tumors better outcomes
in short follow-up.
Given the limitations in renal biopsies, though increasingly progressing
(1), further improvements in our capacity of identifying patients with
high-grade disease and those at increased risk for poor outcomes would
be essential to warrant widespread safe enucleations.
Although this study and others showing a small proportion of clinical
recurrence for positive margin (2) encourage urologists to perform nephron-sparing
surgery, even if the anticipated resection margin is close and touches
the collecting system or renal hilum, an intensive surveillance with
closer and longer follow-up is needed in such special situations, warranting
timely rescue measures, being the cost and burden of serial imaging
significant.
Moreover, residual cancer cells may require many years to become clinically
apparent, since the average annual growth rate of radiographically visible
masses can be as small as 0.13 cm/year (3) with rare but real potential
to metastases, leaving concerning to longer follow-up.
While the benefits of nephron sparing surgery in terms of preventing
chronic kidney disease and its associated cardiovascular morbidity and
potential mortality are progressively clear (4,5), selection bias, variations
in technique, tumor size and location make adequate evaluation of the
enucleation and its comparison to standard partial nephrectomy difficult.
Additionally, it is well recognized the phenomenon that despite increased
detection and treatment of small tumors, mortality from RCC did not
decrease (6), suggesting a lead time bias which uniquely joins kidney
and prostate cancer; most patients will very likely die with their cancer
rather than of their cancer.
Further prospective, randomized and unbiased studies with technique
standardization are necessary and advance in the identification of clinically
significant tumors will be important in determining the renal masses
needing treatment, as well as the well-adjusted treatment in each case.
To the future, the answer needed is probably: when is enucleation necessary
and safe?
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Dr.
Leonardo Oliveira Reis
Assistant Professor of Urology
University of Campinas, Unicamp
Campinas, São Paulo, Brazil
E-mail: reisleo@unicamp.br |