| Objective: Obesity is now defined as a global pandemic, with over 1 billion adults classed as overweight and another 500 million defined as obese. It is predicted that over half of the world’s population will be obese by 2030. Obesity is associated with an increased risk of and poorer prognosis in several cancers, including endometrial, colon and breast cancer. Body mass index(BMI) is a measure of body fat. Systemic inflammatory response has an independent effect on the prognosis of solid tumors, including gastric cancer, pancreatic cancer, colon cancer. However, SII is based on the comprehensive indices of peripheral lymphocytes, neutrophis and platelets, which may be more comprehensive to reflect the balance between host inflammation and immunity. Today, breast cancer has become the most common cancer that affecting women’s health in the world. With the improvement of radiotherapy technology, the application of novel chemotherapy drugs, endocrine therapy and targeted drugs, breast cancer has become one of the solid tumors with the best therapeutic prognosis. But the major clinical problem is the resistance of endocrine therapy at present. Only approximately 70% of patients during the initial treatment have obvious treatment efficacy, even though estrogen receptor and progesterone receptor are both positive. It is important to identify the predicting factors for the resistance to endocrine therapy of breast cancer. For luminal breast cancer, both primary and secondary endocrine therapy resistance are the major factors for affecting its recurrence, and it is a clinical problem to be solved. To explore the correlation among BMI, preoperative systemic immune-inflammation index(SII) and endocrine therapy resistance in patients with luminal breast cancer, and to evaluate the impact of BMI and preoperative SII on disease-free survival(DFS) in patients who underwent radical surgery for luminal breast cancer.Methods: A retrospective study was conducted in 161 patients with luminal breast cancer who underwent curative resection in Hebei General Hospital from 2008-10-01 to 2013-12-31. Pathological examination was carried out at the Department of Pathology in Hebei General Hospital. All patients receiving standard chemotherapy and/or radiotherapy after surgery were positive for hormone receptors and treated with endocrine therapy after chemotherapy and/or radiotherapy. Premenopausal patients were subjected to the treatment of tamoxifen as an endocrine drug, and postmenopausal patients were subjected to the treatment of tamoxifen or aromatase inhibitors(AIs).The patients’ clinical parameters including age, menopausal status, pathological subtype, TNM stage, lymph node metastasis, vascular tumor thrombus, luminal subtype preoperative BMI and SII were collected and classified. Follow-up was performed by hospital visiting, telephone or mail, and counted from the first day when patients were subjected to the treatment of endocrine drug, and ended at 2015-05-31 or the date of patients with drug resistance. SPSS 19.0 statistical software was adopted for statistical analysis. According to the ROC curve, the best demarcation point of SII was determined. The data were determined by χ2 test or Fisher’s Exact test. Spearman rank correlation was used to analyze the association between two variables. Kaplan-Meier method was performed to assess the resistance rate of endocrine therapy, and log rank was used to evaluate the difference among groups. The COX regression model was used to analyze the effect of all factors on endocrine therapy resistance. ROC curves were used to compare the diagnostic values of BMI, SII, and clinical pathological characteristics for endocrine therapy resistance in patients with luminal breast cancer. The statistically significant difference was considered at P < 0.05.Results:1 The percentages of high BMI group in the age <50 years old and ≥50 years old were 84.2%(48/57) and 69.2%(72/104), respectively, and the difference between two groups was statistically significant(X2 = 4.353, P = 0.037). The resistance rates in normal and high BMI groups were 19.5%(8/41) and 50.8%(61/120), and the difference between two groups was statistically significant(X2 = 12.241, P = 0.000).2 The percentages of high SII group in without and with vascular tumor thrombus were 70.3%(71/101) and 96.7%(58/60), respectively, and the difference between two groups was statistically significant(X2 = 16.435, P = 0.000). The resistance rates in low and high SII groups were 9.3%(3/32) and 51.2%(66/129), and the difference between two groups was statistically significant(X2 = 18.28, P = 0.0002).3 The number of patients with normal BMI and low SII is 27, and the number of those with high BMI and high SII is 35. Spearman rank correlation analysis showe that BMI was significantly positively correlated with SII(r=0.245, P=0.002).4 The resistance rates in the normal BMI group after endocrine therapy for 1, 3 and 5 years were 2.4%, 48.8% and 92.7%, respectively, and the resistance rates in high BMI group after endocrine therapy for 1, 3 and 5 years were 20.8%, 77.5% and 98.3%, respectively. The difference between two groups was statistically significant(X2 = 15.154, P = 0.000).5 The resistance rates in the low SII group after endocrine therapy for 1, 3 and 5 years were 3.1%, 50% and 84.4%, respectively, and the resistance rates in high SII group after endocrine therapy for 1, 3 and 5 years were 19.4%, 74.4% and 100%, respectively. The difference between two groups was statistically significant(X2 = 18.891, P = 0.000).6 In the COX regression model, the score test and the likelihood ratio test showed statistically significant difference(P < 0.05). The relative risk factors of SII, BMI and TNM stage were 5.734, 1.664 and 1.303(P < 0.05), respectively; suggesting that the risk factor of endocrine therapy resistance in high SII group was higher by 5.604 times when compared with that in the low SII group, and the risk factor of endocrine therapy resistance in high BMI group was higher by 1.664 times when compared with that in the low BMI group. BMI, preoperative SII and TNM stage were the independent prognostic markers for the resistance to endocrine therapy after radical operation in patients with breast cancer.7 In order to compare BMI, SII, age, menstrual status, lymph node metastasis, vascular tumor thrombus, TNM stage, pathological subtype and luminal subtype, the area under the curve(AUC) of BMI and SII were 0.636 and 0.661, respectively. and there was no difference between the two groups(P > 0.05). However, the AUC of the two groups were higher than other clinical cases, and the difference between the two groups was statistically significant(P < 0.05).Conclusion:1 The age of patients whose BMI≥23kg/m2 is less than the age of those BMI < 23kg/m2. No significant difference was observed among luminal subtype, pathological subtype, lymph node metastasis, vascular tumor thrombus, menstrual status and TNM stage(P>0.05).In the present study, 161 patients with luminal breast cancer have been used to confirm the higher incidence of vascular tumor thrombus in the high SII group when compared with the low SII group. No significant difference was observed among luminal subtype, pathological subtype, lymph node metastasis, age, menstrual status and TNM stage(P>0.05).2 BMI, preoperative SII and TNM stage were the independent prognostic markers for the resistance to endocrine therapy in patients with luminal breast cancer after radical operation.3 Preoperative BMI larger than 23 kg/m2 or preoperative SII larger than 518×109/L may be the predictors of poor disease free survival(DFS).4 The diagnostic values of BMI and SII for the resistance to endocrine therapy were higher than other conventional clinical indices. |
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