Discussion
The prevalence of being overweight or obese has increased by 27.5% for
adults, and obesity continues to be a major health problem worldwide17. The risk for multiple medical problems that can
adversely affect surgical outcomes is increased in obese patients18. The relationship of BMI with bladder cancer and
radical cystectomy has been the subject of scientific research in the
past decade. However, in the literature, the results regarding the
effect of obesity on the surgical and oncological outcomes of patients
after RC for BC are still contradictory 2,9-12. In
this study, we evaluated the effect of BMI on oncologic and surgical
outcomes in patients who underwent radical RC for BC. We found that the
operation time and oral feeding start were longer and major
complications were more common in obese patients. The results revealed
that the mean OS, CSS, RFS, and MFS was shorter in cases with
BMI>29.9kg/m2 compared with other BMI groups, however, the
differences were not statistically significant.
Due to greater technical challenges, many studies reported that
increased BMI is independently associated with perioperative and
postoperative risks after RC. In a study on 1293 patients who underwent
radical cystectomy, Tyson MD et al., by comparing patients with
BMI<30 and patients with BMI ≥30, found that obese patients
had longer operation time and more renal failure and \soutthey noted
no differences in 30-day mortality after RC 19. In
another study, Maurer \soutand T et al, by comparing normal weight,
and overweight patients who underwent RC, revealed that there was no
significant difference according to intraoperative blood transfusion
rate, postoperative TNM stage, and postoperative complications. They
noted that the time of surgery was significantly prolonged and
postoperative bleeding was more common in overweight patients13. After analyzing the data of 671 patients who
underwent radical cystectomy, Gierth M et al reported that, there was no
significant relationship between obesity and tumor stage, grade, lymph
node metastasis, blood loss, urinary diversion type, and 90-day
mortality. Severe complications within 30 days after RC, blood
transfusion rates were higher and the mean operation time was longer in
patients with BMI ≥30 kg/m2 compared to the other BMI
groups 20. Another study by Lee et al showed that
number of complications is higher in obese patients, but complication
severity was similar between BMI groups 21. In our
study, statistically significant major complication rate was observed in
Group 3 compared to Group 1 and 2 (p=0.025 ).
Increased BMI is associated with risk for many cancers, including
urological cancers. It is also thought that cancer is associated with
poor prognoses 22-24. Many studies \soutevaluating
examined the relationship between obesity and oncological outcomes of RC2,11,12,20,25. In multivariable analysis of 4118 RC
patients due to BC, Chromecki et al found that patients with
BMI> 30 had higher disease recurrence (HR 1.67, 95% CI
1.46 – 1.91, P < 0.001), lower CSS (HR 1.43, 95% CI 1.24 –
1.66, P < 0.001), and lower OS (HR 1.81, CI 1.60 – 2.05, P
< 0.001). They thought that, this finding might be related to
the metabolic syndrome seen in obese patients 25. In
another study, Dabi et al. found that the risk of disease recurrence or
cancer-specific mortality increased by 1.5 fold for obese patients. They
reported that increased BMI is an independent prognostic factor for
oncological results of BC patients who underwent RC 2.
In literature, conflicting findings have also been reported. In a
retrospective study, which analyzed the data of 300 patients who
underwent cystectomy (radical or partial) due to BC and whose median
follow-up was 39 months, Hafron J et al showed that the increase in BMI
has no effect on OS or disease-specific survival in univariate or
multivariate analysis. In addition, they found that age over 65 years,
tumor stage, smoking, and the positive tissue margin were significant
factors affecting OS 11. Also, Gierth et al. found
that increased BMI had no effect on survival and not associated with
more aggressive tumor biology 20. On the other hand,
Kwon et al reported that overweight and obesity were associated with
favorable pathological features and prognosis in patients with bladder
cancer undergoing radical cystectomy [12]. Our study showed that the
increase in BMI does not have a statistically significant negative
effect on DSS and OS
The surgical approach is another point of discussion. The guidelines
have recommended that none of the surgical approaches (open-,
laparoscopic- or robotic RC) has clearly shown superiority in terms of
functional or oncological results. In the CORAL study, a prospective
study by Khan et al, the authors found no difference in 5-yr RFS, CSS,
and OS rates of patients who underwent open, laparoscopic and robotic
radical cystectomy for management of bladder cancer. Minimally invasive
techniques achieved equivalent oncological outcomes to the gold standard
of ORC 26. After analyzing robot-assisted radical
cystectomy (RARC) cases, Butt et al found that, overweight and obese
patients had similar complication rates, operative times and estimated
blood loss compared with patients with normal BMI 27.
Ahmadi et al showed that, BMI was not associated with significant
differences in peri-operative, pathological or early oncological
outcomes in patients undergoing RARC 28. In our study,
we did not include the RARC cases, as the number of those patients was
very low. We found no statistically significant effect of surgical
approach (open or laporoscopic) in terms of OS and CSS.
The present study has some limitations. Data collection and analysis was
retrospective and non-randomized. Therefore, unidentified confounding
variables may have an effect on the results. Another limitation was the
performance of procedures by 8 high-volume surgeons in 6 different
centers. However, this limitation is always present in such multicenter
studies. Moreover, lack of central pathologic assessment is also a
limitation.