Twenty-Five Year Trends in the Incidence of Ductal Carcinoma in Situ in US Women.

BACKGROUND: The rising incidence of ductal carcinoma in situ (DCIS) since the widespread enactment of mammography screening has been well documented. Patterns in DCIS incidence among women of various ages and across different racial and ethnic groups have not been well described.

STUDY DESIGN: The Surveillance, Epidemiology, and End Results public-use data set was queried for all women aged 40 years and older diagnosed with DCIS between 1990 and 2014. Annual age-adjusted incidence rates were compared among white, black, Hispanic, and Asian-Pacific Islander women. Additionally, using mammography screening data obtained from the CDC, patterns in mammography screening over time and as they relate to DCIS incidence rates by race and ethnicity were evaluated.

RESULTS: We identified 200,400 women aged 40 years or older with DCIS. Between 1998 and 2014, a period that saw flux in national breast screening guidelines, DCIS incidence rates increased in blacks, Hispanics, and Asian-Pacific Islanders, but remained relatively unchanged in whites (increase in number of DCIS diagnoses per 100,000 individuals in the population per year among blacks +0.66/p < 0.01, Hispanics +3.0/p < 0.01, Asian-Pacific Islanders +0.53/p < 0.01, and whites +0.07/p = 0.21). After accounting for age, year of diagnosis, and mammography screening rates, DCIS incidence was found to be similar between white and black women (0.8 fewer diagnoses per 100,000 individuals compared with whites; p = 0.36) but lower for Hispanic women (9.7 fewer diagnoses per 100,000 individuals compared with whites; p < 0.01).

CONCLUSIONS: The DCIS incidence rates are influenced substantially by breast cancer mammography screening patterns. However, differences exist by race and ethnicity and are not fully explained by screening mammography trends alone. Consideration should be given to including race and ethnicity in determining optimal breast screening guidelines.