| Objective: Breast cancer is the malignancy with the highest morbidity and mortality in women,and 90.0% of the deaths are caused by metastasis-related diseases.The second most common site of metastatic breast cancer is the lung,with an incidence of about 30.0%.Large clinical trials and reasonable treatment guidelines for breast cancer patients with pulmonary metastases are still inadequated.Therefore,a deeper understanding of the clinicopathological characteristics and related prognostic factors of breast cancer with lung-only metastases is of great significance,which can provide more evidence-based medicine basis for individualized treatment of breast cancer patients with lung metastases.Methods: 17,869 cases of stage IV breast cancer that met our criteria from January 2010 to December 2015 were selected from the SEER database in the United States.For the purpose of the study,the population was first divided into the lung-only metastases,the lung + other site metastases and the extrapulmonary metastases.The clinicopathological data of all patients were analyzed and the chi-square test was used to calculate the statistical relationship between these variables and metastasis.Multivariate Logistic regression analysis of the influencing factors of lung metastasis of breast cancer;Kaplan-Meier method and Cox proportional risk model were used for statistical analysis to evaluate the predictive value of these factors in breast cancer with lung-only metastases.Results: Among the 17,869 of stage IV breast cancer,there were 1,779(10.0%)lung-only metastases,3,555(19.9%)lung + other site metastases,and 12,535(70.1%)extrapulmonary metastases.There were 5334 breast cancer of lung metastases,accounting for 29.9% of all.The factors influencing the occurrence of lung-only metastases include age at diagnosis,marital status,race,histologic type,BC subtype,T stage,resection of the primary breast lesion and radiotherapy.The median survival time of OS and BCSS were 27 months and 33 months,respectively.The 1-year and 3-year survival rates were 70.7% and 42.1%,respectively.The multivariate COX analysis shows,the lung-only metastases breast cancer patients,who were white or <55 years old,the OS it better than who were black or >=55.Well differentiated one used as control,Undifferentiated(HR=2.016,95%CI=1.060-3.835,P=0.033),and poorly differentiated(HR=1.971,95%CI=1.360-2.855,P<0.001)were the risk factors.Use T1 as control,the HR of T2,T3 and T4 were 1.276(95%CI=1.006-1.617,P=0.044),1.443(95%CI=1.123-1.855,P=0.004),1.809(95%CI=1.452-2.253,P<0.001),respectively.HR-/HER2-was 2.886 times more likely to die than HR+/HER2-(P<0.001).Both surgery and chemotherapy were protective factors(P<0.001).Multiple Cox analysis results of the recombination of surgery and chemotherapy showed that surgery,chemotherapy,surgery and chemotherapy were all beneficial to BCSS,but the difference in prognosis between surgery and chemotherapy was not statistically significant(P=0.844).K-m analysis of HR-/HER2-patients was conducted to find that different treatment methods had statistically significant difference in BCSS,log-rank test P<0.001.HR-/HER2-patients who underwent surgery and chemotherapy had the best prognosis,with median survival of 22 months.Conclusions: Breast cancer with lung-only metastases were more common in the patients with 55-79 years old,invasive ductal carcinoma,poorly differentiated,HR+/HER2-and HR-/HER2-patients.The patients who were older,who have the lower degree of differentiation and the higher stage T,the risk of developing lung metastasis was higher.HR-/HER2-had the highest risk of metastasis in BC subtype.The patients who were younger,the white,who received surgery and chemotherapy were all protective factors.However,there was no significant difference in prognosis between surgery and chemotherapy,and the surgery + chemotherapy group had the best prognosis. |
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