Breast Cancer Subtype Incidence in the United States for 2011
The current annual report of cancer statistics by the American Cancer Society, Centers for Disease Control and Prevention, National Cancer Institute, and North American Association of Central Cancer Registries includes a focus on breast cancer incidence by subtype using new national-level data. The report is presented in the Journal of the National Cancer Institute by Kohler et al. Key findings are summarized below.
- Data are based on a total of 178,125 invasive breast cancer cases diagnosed in 2011 in states with high-quality registries.
- Hormone receptor–positive/HER2-negative disease was the most common subtype, accounting for 73% of cases. The age-adjusted rate per 100,000 women was 86.5, compared with 15.5 for triple-negative, 12.4 for hormone receptor–positive/HER2-positive and 5.5 for hormone receptor–negative/HER2-positive disease.
- Rates of hormone receptor–positive/HER2-negative disease were higher than other subtypes in every racial/ethnic group.
- Rates of hormone receptor–positive/HER2-negative disease were comparable among women aged < 45 years across racial/ethnic groups, but the rate was higher in white women vs other groups among older women.
- Triple-negative cancers accounted for 13% of all cases; the age-adjusted rate among black women was 27.2 per 100,000, 1.9 times higher vs white women, 2.3 times higher vs Hispanic women, and 2.6 times higher vs Asian/Pacific Islander women.
- Triple-negative cancers were the second most common subtype in black women in all age groups, in those aged > 45 years among white women, and those aged >55 years among Asian/Pacific Islander and Hispanic women.
- Hormone receptor–negative/HER2-positive cancer accounted for 5% of all cases and had the lowest rate in all racial/ethnic groups.
- Hormone receptor–positive/HER2-positive cancer accounted for 10% of all cases; rates were similar to triple-negative disease in all racial/ethnic groups except for black women, who had a higher rate of triple-negative disease.
- All subtypes were most commonly diagnosed at a local stage and least commonly diagnosed at a distant stage in all racial/ethnic groups. Black women had the highest rate of cancer diagnosed at a distant stage across every subtype.
- Among hormone receptor–positive/HER2-negative cases, rates of moderately differentiated cancer were highest for all racial/ethnic groups and rates of poorly differentiated and undifferentiated cancers were lowest for all groups except for black women. For all other subtypes, rates of poorly/undifferentiated grade cases greatly were higher vs more favorable grades in every racial/ethnic group. Rates of poorly/undifferentiated cases were highest for triple-negative breast cancers among black women.
- Rates of hormone receptor–positive/HER2-negative cases decreased with increasing poverty for every racial/ethnic group, with the highest rate (98.69 per 100 000) in white women living in low-poverty areas. No clear relationships between poverty and incidence of other subtypes were observed for any racial/ethnic group.
- Triple-negative cancer rates were lower than the national average in the northwest and higher in the southeast.
- Rates of hormone receptor–positive/HER2-negative cancer were generally higher in states with higher mammography screening rates. Rates were highly correlated with self-reported mammography rates for white women (r = 0.57, P < .001) and moderately correlated for black, Asian/Pacific Islander, and Hispanic women combined (r = .33, P = .033).
The investigators concluded: “There are unique racial/ethnic specific incidence patterns for breast cancer subtypes; likely because of both biologic and social risk factors, including variation in mammography use. Breast cancer subtype analysis confirms the capacity of cancer registries to adjust national collection standards to produce clinically relevant data based on evolving medical knowledge.”
Betsy Kohler, MPH, of North American Association of Central Cancer Registries, Springfield, Illinois, is the corresponding author for the Journal of the National Cancer Institute article.
This work was supported by the American Cancer Society, Centers for Disease Control and Prevention, National Cancer Institute, and North American Association of Central Cancer Registries.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
