Research Of The Occurrence, Development And Prognostic Factors Of Breast Cancer Associated With Body Mass Index

Background and ObjectiveBreast cancer is the most prevalent malignant tumor among women worldwide.And it is the leading cause of cancer death among women in developing countries. At present, obesity is increasingly recognized as a global public health problem, the proportion of the population obese is increasing, and it is a risk factor for many diseases. The relationship between obesity and breast cancer is currently controversial.According to the correlation of the occurrence, development and prognostic factors of breast cancer and obesity, our study aimed to evaluate the relation of obesity and breast cancer occurrence and development, and the mechanism of obesity on the prognosis of breast cancer to provide clinical basis and help for early prevention and prognosis of breast cancer.Materials and Methods928 cases of women breast malignant tumor patients who accepted treatment in China Japan Union Hospital of Jilin University from September 2013 to September2015 were chosen as the case group. And 950 cases of women benign breast disease at the same period in our hospital were selected as the control group including the age,weight and height. According to the adult weight criteria of China, we divided these 2groups into 4 subgroups: underweight, normal weight, overweight and obesity group and compared the difference of BMI; according to the age, we divided these 2 groups into < 40 years, 40-49 years, 50-59 years, ≥ 60 years subgroups, and compared the BMI of these 2 groups in each subgroup. The case group and control group were analyzed by using the logistic regression analysis method to investigate the relationship of age, BMI and the risk of breast cancer. To explore the relationship of BMI and the development and prognosis factors of breast cancer, we collected the data of pathology, Immunohistochemistry and breast tumor markers in the case group,divided this group into 4 subgroups(underweight, normal weight, overweight and obesity) or 2 subgroups(obesity and non-obesity) and then compared the difference of tumor size, axillary lymph nodes metastasis, histological grade, molecular subtype,ER/Her-2, CEA/CA153 expression in BMI subgroups. We used Microsoft Excel 2010 software to input and organize the data, SPSS 22.0 database software to analyze the data statistically.Results1. The group of breast cancer patients was at the age of 23-78 years old, the median age was 50; the control group of patients was aged between 18-69 years old, the median age was 42.2. The average BMI of the breast cancer patients was 24.07 ± 3.40 Kg/m2,15.24-39.74 Kg/m2; the average BMI of the control group was 23.14 ± 3.41 Kg/m2,15.24-37.50 Kg/m2. The distribution of BMI between these 2 groups was statistically significant(P< 0.01), the constituent ratio of overweight and obesity group of breast cancer were higher than that of normal weight group(P< 0.01). In age subgroups, the BMI of 2 groups had no statistically differences in < 50 years old subgroups(P> 0.05);the BMI of breast cancer group was significantly higher than that of control group(P <0.01).3. Increasing age and BMI were risk factors for breast cancer(OR= 1.041, 95%CI:1.011~1.073; OR= 1.090, 95%CI: 1.078~1.101).4. The tumor size of 4 subgroups of BMI was statistically significant, size of obese subgroup was significantly higher than that of other three subgroups(P< 0.01); positive expression of ER/Her-2 had no statistically difference in the 4 subgroups(P> 0.05).5. The histological grade, molecular subtype and CEA of breast cancer in BMI 2subgroups had no statistically difference(P> 0.05); the number and rate of the positive axillary lymph nodes metastasis of obesity subgroup was higher than that of non-obese subgroup(P< 0.05); the positive rate of CA153 in obese subgroup was significantly higher than that in non-obese subgroup(P< 0.01).Conclusion1. The BMI of breast cancer patients was significantly higher than that of benign breastdisease patients, the differences in the groups of above 50 years old were more significant.2. Increasing BMI and age are risk factors for breast cancer.3. Tumor size, positive axillary lymph nodes metastasis rate and number, expression of CA153 are totally related to obesity positively; and histological grade, molecular subtype and ER/Her-2 of breast cancer have no correlation with obesity. Obesity can promote the development and metastasis of breast cancer, but has no significant correlation with the type of breast cancer occurrence and malignant degree.4. Obese breast cancer patients with poorer prognosis may be associated with their larger tumor size, higher rate and number of lymph nodes metastasis.