Relationship between serum lipids and endometrial cancer: A systematic review and meta-analysis

Introduction: Endometrial cancer is the fifth most common cancer in females worldwide. One of the most important risk factors for endometrial cancer is obesity. The relationship between obesity and endometrial cancer is due to the exposure to biological agents produced in the adipose tissue. In general, the presence of lipids is essential for the growth and development of cancer cells. Given the limited studies regarding the association between lipid profile and endometrial cancer and their contradictory results, the present systematic review and meta-analysis was conducted to bridge this gap. Methods: For the purpose of the study, the studies related to the issue of interest and published until November 2017 were searched in Google Scholar search engine and several international databases, including PubMed, Elsevier, Scopus, web of knowledge, and SID, by two authors independently. The search process was accomplished using the following keywords alone or in combination: "lipid", "lipoprotein", "cholesterol", "LDL cholesterol", "HDL cholesterol", "triglyceride", "dyslipidemia", "endometrial cancer", "endometrial carcinoma", and "endometrial neoplasm". The MOOSE instruction was employed to perform and report this meta-analysis. The data were analyzed using Stata statistical software, version 14. Results: A total of 369,649 subjects participated in the eight reviewed studies, 2,809 of whom were inflicted with endometrial cancer, while the rest were healthy. The combined estimates of the relative risk for total cholesterol and high-density lipoprotein (HDL) cholesterol were 1.21 (95% CI: 0.98-1.45) and 1.11 (95% CI: 0.74-1.48), respectively. This value was obtained as 1.09 (95% CI: 1.10-1.71) and 1.47 (95% CI: 1.10-1.85) for the highest low-density lipoprotein (LDL) and triglyceride levels, respectively, compared to the lowest levels. Conclusion: As the findings indicated, serum triglyceride levels were associated with endometrial cancer. However, this cancer showed no relationship with total cholesterol, HDL, and LDL levels