Discussion:
With the increasing prevalence of MetS, the number of studies on MetS
etiology and MetS -related diseases has also increased. Considering that
MetS and its components should be evaluated in a broader spectrum, a
concept termed metabesity has been introduced with the increasing
recognition of their relationship with cancer [16]. In our study, it
was concluded that the patients with MetS had a larger tumor size and a
higher Fuhrman grade than those without MetS, but there was no
difference between the two groups in terms of the pathological stage.
There are many studies examining the relationship between DM and RCC. It
is still controversial whether DM itself or DM-related diseases increase
the risk of RCC [17]. Some autopsy studies have found an increased
prevalence of DM in patients with kidney cancer [18, 19]. Compared
to the general population, the morbidity and mortality of RCC increases
in patients with DM. Type 2 DM has been shown to be associated with an
increased risk of RCC in women [20, 21]. DM has also been found to
have a negative effect on disease progression and recurrence, and a
significant difference has been determined in 5-year recurrence-free
survival between patients with and without DM. It has been determined
that preoperative high hemoglobin A1c predicts postoperative progression
[22, 23]. There are studies showing that patients with DM have a
significantly higher Fuhrman grade and a larger tumor size than patients
without DM. Metformin, one of the common oral anti-diabetic drugs, can
inhibit the growth of RCC cells in vivo and in vitro. Several studies
have demonstrated the inhibitory effect of metformin on many tumor
cells, including RCC cells [24-26]. Contrary to these studies, Habib
et al. found that the tumors of patients with DM tended to be smaller in
size and there was no relationship between blood glucose level and tumor
size [27]. In our study, a statistical difference was found between
the patients with a diagnosis of DM and those without a diagnosis of DM
in terms of tumor size and Fuhrman grade, but the correlation between
pathological T stages could not be analyzed.
HT, one of the MetS components, is another risk factor. It has been
confirmed by numerous clinical studies that HT can increase the risk of
RCC [28, 29]. Although the etiopathogenesis of this increased risk
is not completely known, renal damage, inflammation, and increased
susceptibility to carcinogens secondary to HT are thought to increase
the risk of RCC [30]. In the literature, there are also studies
showing that antihypertensive treatment increases the risk of RCC
[31]. However, there is a need for large-scale studies to clarify
the effect of especially diuretic-like antihypertensive drugs on the
development of RCC. In our study, the patients with a diagnosis of HT
and those without a diagnosis of HT at the time of surgery were compared
for tumor size, tumor grade, and stage, regardless of the duration of
having HT, the type of medication received, and the blood pressure
levels. Although it was found that the patients with a diagnosis of HT
had a larger tumor size and a higher pathological T stage, there was no
significant difference between the patients with and without a diagnosis
of HT in terms of Fuhrman grade.
There are many studies showing that dyslipidemia, one of the components
of MetS, plays a role in the development of various cancers. The
relationship between high TGL and esophageal and colon cancer has been
demonstrated in the literature [32, 33]. The fact that clear cell
RCC, the most common type of RCC, is histologically characterized by
sterol accumulation in tumor cells suggests that lipid metabolism is
effective in the formation and progression of RCC. Statins commonly used
for the treatment of lipid disorders, especially hypercholesterolemia,
have been reported to provide protection against the development of RCC
and have an inhibitory effect on tumor growth, invasion, angiogenesis,
and metastasis in vitro. Experimental evidence shows that deregulated
cholesterol and lipid biosynthesis plays an important role in the
development of RCC [34, 35]. Contrary to these studies, there are
also studies showing lower cancer incidence and mortality in patients
with high serum TGL levels, as well as studies showing the existence of
a relationship between low cholesterol levels and increased cancer
incidence [36-38]. According to the results of our study, both
patients with low HDL and patients with elevated TGL had a statistically
significantly larger tumor size, higher Fuhrman grade, and more advanced
pathological T stage than those with low HDL and those without elevated
TGL.
Obesity is a risk factor for RCC and there is a relative increase in RCC
risk in direct proportion to the severity of obesity, especially in
women. It has not yet been definitively demonstrated how obesity
increases the risk of kidney cancer [39, 40]. Currently, there are
studies showing that an increased BMI in both genders and being
overweight in late adolescence are effective in the development of RCC
[41, 42]. Contrary to these studies, Parker et al. found that
patients with a high BMI tended to have less aggressive tumors [43].
In our study, obese patients had a larger tumor size and a worse Fuhrman
grade, but no interpretation could be made about the pathological stage.
In conclusion, it was found that patients with MetS or the components of
DM, HT, low HDL, elevated TGL, and obesity had a statistically
significantly larger tumor size, and patients with MetS or DM and obese
patients had a worse Fuhrman grade, while patients with HT had a more
advanced pathological stage. Since there were no patients with DM or
obese patients with pathological stage 4 in the study, no interpretation
could be made about the relationship between DM, obesity, and the
pathological stage. Patients with dyslipidemia were found to have a
larger tumor size, a worse Fuhrman grade, and a more advanced
pathological stage. Based on these data, the worst effect is seen in the
presence of dyslipidemia in terms of a single component. If these
results are supported by similar studies, the relationship of MetS and
its components with RCC will be revealed more clearly.
Conflict of Interest: No conflict of interest was declared by
the author.
Financial Disclosure: The author declared that this study has
received no financial support