Study objectives: To investigate the association between race/ethnicity and histologic types of breast cancer.
Design: Cross-sectional study.
Setting: Population-based data from the Northern California Tumor Registry, which is part of the National Cancer Institute's Surveillance, Epidemiology and End Results Program.
Participants: A total of 2759 breast cancer cases diagnosed in 1988.
Main results: Tumors were classified as ductal, lobular, and mixed/unspecified carcinoma. Ductal carcinoma was the most common (83.6%) and lobular carcinoma was the rarest. Most cases were diagnosed in the localized stage (56.3%). Caucasian women had the highest rates of total breast cancer (240.9/100,000), ductal and lobular. In African-American women, the odds of ductal carcinoma were twice that of lobular carcinoma, compared with Caucasian women (odds ratio [OR] = 2.0, 95% confidence interval [CI] 1.0-3.9) after adjusting for age, site, and stage at diagnosis. Similarly, Asian and Hispanic women also had higher, non-statistically significant odds of ductal versus lobular carcinoma compared with Caucasians (OR = 1.8 [95% CI 0.9-3.7] and 1.6 [95% CI 0.8-3.4], respectively).
Conclusions: Future studies should investigate how racial/ethnic differences in histology among breast cancer patients will influence life expectancy, against a backdrop of health care access, sociocultural issues, lifestyle habits, reproductive history, family history, and tumor characteristics.