Assessing Risk Factors for Invasive Breast Cancer Patients with Ductal Carcinoma In Situ (DCIS) Diagnosis Study, Virginia (2007-2021)
Shuhui Wang, M. S.,Epidemiologist-Senior, Sravani Yakkanti,
Virginia Cancer Registry
Virginia Department of Health
INTRODUCTION
Breast cancer is the most common cancer in women in the United States. Ductal carcinoma in situ (DCIS) is a pre-cancerous condition that starts in a milk duct and has not grown into the rest of the breast tissue. The American Cancer Society’s estimates for DCIS are 56,500 new cases in 2024. In Virginia, around 15% of breast cancer tumor diagnoses are DCIS cases.
With the improvements in screen-film technology in the 1980s and 1990s, mammography screening for breast cancer became more common in the United States. Technological improvements and regulations for mammograms helped detect more DCIS cases.
From 1995 to 2021, in situ cases increased by 179.4% in Virginia. DCIS had been considered rare (2–3%) in the pre-mammographic era, but now comprises approximately 20–25% of screen-detected breast cancer cases in the United States.
Many DCIS cancers later progress to invasive breast cancer, with or without treatment. However, it is not possible to accurately predict which DCIS would be more likely to progress to invasive breast cancer. Thus, assessing risk factors for DCIS-invasive breast cancer (IBC) progression is very important.
METHODS
VCR Epidemiologist’s extracted all female breast Ductal Carcinoma In Situ (DCIS) patients diagnosed between 2007 and 2011 from the Virginia Cancer Registry live database. We then linked them with patients who had malignant breast cancer diagnosis from July 2011 to the end of 2021.
The time interval between two diagnoses was at least six months. After data cleaning and manipulation, there were N=6444 patients in the study. Among those patients, 485 (7.5%) were diagnosed with an invasive female breast cancer after six months or more.
A logistic regression model was applied, with the stepwise selection to examine the association between smoking status, alcohol status, age, race, and family history and the invasive cancer diagnosis for DCIS patients.
The analysis was conducted using SAS 9.4. We also conducted the odds ratio test to compare the relative odds of progressing to invasive breast cancer given exposures to the risks (family history, alcohol, tobacco, race, age at DCIS DX).
“No matter what the statistics say, there is always a way”
– Bernie Siegel
