The Clinicopathological features and survival outcomes of patients with different metastatic sites in stage IV breast cancer.
BACKGROUND
The features and survival of stage IV breast cancer patients with different metastatic sites are poorly understood. This study aims to examine the clinicopathological features and survival of stage IV breast cancer patients according to different metastatic sites.


METHODS
Using the Surveillance, Epidemiology, and End Results database, we restricted our study population to stage IV breast cancer patients diagnosed between 2010 to 2015. The clinicopathological features were examined by chi-square tests. Breast cancer-specific survival (BCSS) and overall survival (OS) were compared among patients with different metastatic sites by the Kaplan-Meier method with log-rank test. Univariable and multivariable analyses were also performed using the Cox proportional hazard model to identify statistically significant prognostic factors.


RESULTS
A total of 18,322 patients were identified for survival analysis. Bone-only metastasis accounted for 39.80% of patients, followed by multiple metastasis (33.07%), lung metastasis (10.94%), liver metastasis (7.34%), other metastasis (7.34%), and brain metastasis (1.51%). The Kaplan-Meier plots showed that patients with bone metastasis had the best survival, while patients with brain metastasis had the worst survival in both BCSS and OS (p < 0.001, for both). Multivariable analyses showed that age, race, marital status, grade, tumor subtype, tumor size, surgery of primary cancer, and a history of radiotherapy or chemotherapy were independent prognostic factors.


CONCLUSION
Stage IV breast cancer patients have different clinicopathological characteristics and survival outcomes according to different metastatic sites. Patients with bone metastasis have the best prognosis, and brain metastasis is the most aggressive subgroup.
['Wang|Ru|R|', 'Zhu|Yayun|Y|', 'Liu|Xiaoxu|X|', 'Liao|Xiaoqin|X|', 'He|Jianjun|J|', 'Niu|Ligang|L|http://orcid.org/0000-0003-3612-928X']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D001943:Breast Neoplasms D005260:Female D006801:Humans D053208:Kaplan-Meier Estimate D008875:Middle Aged D009362:Neoplasm Metastasis D009367:Neoplasm Staging D063868:Patient Outcome Assessment D011379:Prognosis D016016:Proportional Hazards Models D018426:SEER Program D016019:Survival Analysis D055815:Young Adult
Survival outcomes Metastatic sites Breast cancer SEER