Variation in breast cancer subtypes with age and race/ethnicity.
BACKGROUND
Both age and race have been identified as independent predictors of breast cancer subtype but the association of age with subtype within each race is not well understood. This study assesses the association of age with the eight breast cancer subtypes as defined by ER/PR/HER2 among white, African-American, Hispanic, and Asian/Pacific Islander women.


METHODS
This study included 69,358 women with primary invasive breast cancer. Logistic regression was used to assess the association of age with each of the ER/PR/HER2 subtypes for each race adjusted for socioeconomic status, stage, grade, and tumor size.


RESULTS
The odds of African-American women having a triple-negative tumor were not statistically significantly increased for women under 46 when compared to the African-American women aged 46-69 (OR=0.96; 95% CI=0.80-1.16). A similar pattern was observed for the ER-/PR-/HER2+ subtype. Hispanic women under age 46 (OR=0.83; 95% CI=0.71-0.97) and over age 70 (OR=0.71; 95% CI=0.57-0.89) were less likely to have the ER-/PR-/HER2+ subtype. Asian/Pacific Islander women under age 46 also had reduced odds (OR=0.67; 95% CI=0.55-0.82) of the ER-/PR-/HER2+ subtype.


CONCLUSIONS
The ER/PR/HER2 subtypes vary with age and differences in this variation depend on race. It is important to define breast cancer using the ER/PR/HER2 subtype and the significance of age and race should not be overlooked.
Parise
Carol A
CA
Sutter Institute for Medical Research, 2801 Capitol Ave Suite 400, Sacramento, CA 95816, USA.
Bauer
Katrina R
KR
Caggiano
Vincent
V
D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000208:ethnology / Q000473:pathology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012923:Social Class
D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone