The risk factors of skeletal-related events and their influence on survival in breast cancer patients with bone metastases

Abstract

Objective To explore the risk factors of skeletal-related events (SREs) and their influence on the survival of breast cancer patients with bone metastases. Methods Relevant clinical data and outcomes of 123 female breast cancer patients with bone metastases in Shanghai Jiao Tong University Medical School Affiliated Ruijin Hospital between January 2010 and June 2017 were retrospectively reviewed. All patients were divided into SREs group or non-SREs group according to whether SREs occurred at the last follow-up. The clinical features, including age, pathology, molecular characteristics of breast cancer, axillary lymph node metastasis, bone metastasis interval, and number of bone metastasis, were analyzed and compared between two groups. Univariate and multivariate analysis were performed using chi-square test and logistic regression analysis to explore the risk factors for SREs. The prognosis survival difference between the two groups was analyzed by Kaplan-Meier test. Results One hundred and twenty-three consecutive patients with the average age of (53.9±11.3) years (range, 23-78 years) were identified during study period.The number of patients with SREs or non-SREs was 61 cases and 62 cases. There were significant differences in the number of axillary lymph nodes bone metastasis interval, outside the bone metastasis and the number of bone metastases (all P values 0.05). Multivariate analysis showed that the difference of lymph node metastasis and multiple bone metastasis between the two groups was statistically significant(all P values<0.05). Totally, the group of SREs occurred SREs. The frequency of SREs occurrence from high to low in SREs group was radiation therapy for bone metastases (n=34, 35.8%), pathological fracture (n=32, 33.7%), spinal cord compression (n=13, 13.7%), surgery for bone lesion (n=9, 9.5%), hypercalcemia (n=7, 7.4%). Survival analysis showed the median survival time of non-SREs group and SREs group were 54 months and 35 months respectively, and the difference was statistically significant (P<0.05). Conclusions Axillary lymph node metastases and multiple bone metastases are independent risk factors for SREs, and SREs indicate poor prognosis in breast cancer patients with bone metastases. Key words: Bone neoplasms; Neoplasm metastasis; Breast neoplasms; Bone metastases; Skeletal-related events