[A case-control study on the association between serum lipid level and the risk of breast cancer]

Objective: To examine the association between serum lipids, including total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), and the risk and progression of breast cancer in postmenopausal and premenopausal women. Methods: A review analysis of female patients who underwent breast cancer surgery and blood lipid metabolism testing in Tianjin One Hospital, from January 2013 to October 2013, was performed. A total of 1 081 patients were included in the final analysis. The control group consisted of 2 981 women without breast cancer. We collected all of the cases' demographic, pathology, lymph nodes metastasis information, was used to testify the difference of serum lipid level between patient and control group, also the postmenopausal and pre-menopausal groups. Results: The average age of the patients and control subjects were (51.6±0.3) and (51.0±0.2) years, respectively. Serum TC and LDL-C levels in the patient group, (5.16± 0.03) and (3.28±0.26) mmol/L, respectively, were significantly higher than in the control group, (5.02±0.01) and (2.51 ± 0.01) mmol/L, respectively (t values 3.89 and 4.81 and P<0.001). HDL-C levels in the patient group, (1.60±0.01) mmol/L, were significantly lower than in the control group, (1.65±0.01) mmol/L (t=3.90, P<0.001). Similar observations were made in postmenopausal patients. Serum TC and LDL-C levels in the postmenopausal patient group, (5.48±0.04) and (3.27±0.03) mmol/L, respectively, were significantly higher than in control subjects, (5.24±0.02) and (2.71±0.02) mmol/L, respectively (t values 4.75 and 15.30, all P values <0.001). HDL-C levels in postmenopausal patients, (1.60±0.02) mmol/L, were significantly lower than in the control group, (1.69±0.01) mmol/L (t=4.85 , P<0.001). In the breast cancer patient group, those at pathological stages 0-Ⅱ had lower TG levels than those at Ⅲ-Ⅳ. These values were (1.19±0.05) and (1.43± 0.09) mmol/L, respectively (t=2.69, P<0.001). Meanwhile, patients with no lymph node metastases had lower TG levels than the lymph node-positive group, with values of (1.15 ± 0.05) and (1.37 ± 0.07) mmol/L, respectively (t=2.53, P=0.012). Conclusion: We found that dyslipidemia may affect the incidence of breast cancer, particularly among postmenopausal women. Serum lipids may promote cancer progression through higher TG and low HDL-C levels.