title: The impact of nodal micrometastasis on mortality among women with early-stage breast cancer.
abstract: The clinical significance of nodal micrometastasis is debated. Our primary objective was to determine whether, among women with early-stage breast cancer, regional lymph node micrometastasis is an independent risk factor for mortality. The secondary objective was to identify subgroups of women who have the highest risk of death from early-stage breast cancer with micrometastases.
  
  
  
  206,625 women diagnosed with early-stage breast cancer (IA, IB, and IIA) from 2004 to 2012 were identified in the Surveillance, epidemiology, and end results database. Nodal status was classified as node-negative, isolated-tumor cells, micrometastases, and macrometastases. Women were classified into eight ethnic groups. Logistic regression was performed to estimate the odds ratio of being diagnosed with micrometastases. The Cox proportional hazard model was used to estimate the hazard ratio (HR) of breast cancer-specific death associated with micrometastases for each ethnic group.
  
  
  
  The 8-year breast cancer-specific survival was 96.6 % for women with node-negative breast cancers and was 94.6 % for women with micrometastases (adjusted HR 1.49; 95 % CI 1.31-1.69; P < .001). Among women with micrometastases, the 8-year breast cancer-specific survival was 95.1 % for white women and was 90.6 % for black women (HR 1.80; 95 % CI 1.29-2.52; P = .0006).
  
  
  
  Nodal micrometastasis is an independent risk factor for breast cancer mortality among women with early-stage breast cancer. Black women are more likely to die from breast cancer with micrometastases than white women.
authors: Women's College Research Institute/Women's College Hospital, 76 Grenville Street, Toronto, ON, M5S 1B2, Canada.
authors: Javaid
authors: J
authors: Iqbal
authors: Women's College Research Institute/Women's College Hospital, 76 Grenville Street, Toronto, ON, M5S 1B2, Canada.|Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.|Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada.|Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors: Ophira
authors: O
authors: Ginsburg
authors: Women's College Research Institute/Women's College Hospital, 76 Grenville Street, Toronto, ON, M5S 1B2, Canada.|Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors: Vasily
authors: V
authors: Giannakeas
authors: Women's College Research Institute/Women's College Hospital, 76 Grenville Street, Toronto, ON, M5S 1B2, Canada.|Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.|Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada.
authors: Paula A
authors: PA
authors: Rochon
authors: Women's College Research Institute/Women's College Hospital, 76 Grenville Street, Toronto, ON, M5S 1B2, Canada.
authors: John L
authors: JL
authors: Semple
authors: Women's College Research Institute/Women's College Hospital, 76 Grenville Street, Toronto, ON, M5S 1B2, Canada. steven.narod@wchospital.ca.|Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada. steven.narod@wchospital.ca.
authors: Steven A
authors: SA
authors: Narod
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000473:pathology*; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008875:Middle Aged; D060787:Neoplasm Grading; D061206:Neoplasm Micrometastasis; D009367:Neoplasm Staging; D016017:Odds Ratio; D011379:Prognosis; D016016:Proportional Hazards Models; D018426:SEER Program; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor
keywords: Breast cancer; Ethnicity; Lymph nodes; Micrometastasis; Survival