Purpose: To determine whether individual and/or cumulative components of metabolic syndrome (obesity, hypertension, dyslipidemia, and hyperglycemia) are associated with pathologic features of kidney cancer.
Patients and methods: A review of our kidney tumor database identified 462 patients who underwent partial or radical nephrectomy for renal cell carcinoma. The NCEP ATP-III criteria were used to define metabolic syndrome (MetS). Linear fixed effects modeling and ordinal logistic regression examined the relationship between MetS (individual and cumulative components) and pathologic characteristics.
Results: Two hundred and seventy-eight men and 184 women with a median age of 58 years, BMI of 31 kg/m2, tumor size of 3.7 cm, and nephrometry score of 6 were included. Ninety-seven (21 %) patients met NCEP ATP-III criteria for MetS. Hypertension was the only individual component of MetS associated with pathologic features of kidney cancer including increased tumor size [geometric mean ratio 1.17 (1.05-1.32), P = 0.03], higher tumor grade [OR 1.49 (1.03-2.17), P = 0.04], increasing nephrometry score [OR 1.77 (1.28-2.48), P = 0.001], and non-clear cell histology [OR 1.42 (1.01-2.02), P = 0.05]. Furthermore, combinations of MetS components were associated with increased tumor grade (P = 0.02), tumor stage (P = 0.02), nephrometry score (P ≤ 0.001), and non-clear cell histology (P = 0.02), only when hypertension was included.
Conclusion: MetS is composed of four risk factors each implicated in carcinogenesis. We identified hypertension as the primary component associated with specific pathologic features of kidney cancer. Further studies are necessary to elucidate whether the effect of hypertension is a function of severity and/or chronicity.
Keywords: Hypertension; Metabolic syndrome; Renal cell carcinoma.