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