Background: Recent report showed that breast cancer incidence rate in the US stabilized after a sharp reduction in 2002 and 2003. It is important to continue monitoring breast cancer incidence rates according to age group, race/ethnicity, estrogen receptor (ER), and tumor stage.

Methods: Age-standardized breast cancer incidence rates were calculated using data from the Surveillance, Epidemiology, and End Results (SEER) 18 registries from 2000 to 2009, among 677,774 female breast cancer patients aged 20 and above. Jointpoint regression models were used to fit a series of joined straight lines on a log scale to the trends of annual age-standardized rates.

Results: The overall breast cancer incidence significantly increased for non-Hispanic black from 2005 to 2009 (annual percentage change, APC =2.0%, p=0.01) and Asian/Pacific Islanders from 2000 to 2009 (APC 1.2%, p=0.02). Since 2004, incidence rates in women age 40-49 significantly increased for all racial/ethnic groups (overall APC = 1.1%, p=0.001). Incidence rate of carcinoma in situ significantly increased in all racial/ethnic groups (APC ranges from 2.3%-3.0%, p<0.005) and localized breast cancer incidence significantly increased in non-Hispanic blacks (APC=1.3%, p=0.004) and Asian (APC=1.2%, p=0.03). ER positive breast cancer significantly increased in almost all age/race sub-groups after 2005 (APC by race: non-Hispanic white 1.5%, non-Hispanic black 4.3%, Asian/Pacific Islander 1.7%, and Hispanic 1.8%, p-values<0.05), while ER negative breast cancer decreased in most sub-groups (APC by race: non-Hispanic white -3.9%, non-Hispanic black -3.7%, Asian/Pacific Islander -1.5%, and Hispanic -4.3%, p-values<0.05).

Conclusions: Recent incidence of breast cancer appears to be increasing in certain subgroups, including non-Hispanic black, Asian/Pacific Islanders, women 40-49 years old, low-stage breast cancer, and estrogen-receptor positive breast cancer. These changes are unlikely due to mammography screening rate that has remained stable in recent years, but may be partially explained by the transition from film to digital mammography, which has higher sensitivity to detect breast cancer, especially young-onset breast cancer. It deserves further investigation on why the rate of estrogen receptor negative breast cancer declined.

Citation Format: Ningqi Hou, Dezheng Huo. Breast cancer incidence rate in american women started to increase: Trend analysis from 2000 to 2009. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 143. doi:10.1158/1538-7445.AM2013-143