A study has found that a woman's risk of dying of breast cancer within 10 or 20 years of receiving a diagnosis of ductal carcinoma in situ (DCIS) is low. However, the death rate is higher for women who were diagnosed before age 35 and for black women. DCIS is also referred to as stage 0 breast cancer.
Some women with DCIS do develop a second breast cancer (DCIS or invasive). A small proportion of patients with DCIS ultimately die of breast cancer. However, it is not clear what factors might predict mortality after a diagnosis.
For this study, researchers used the Surveillance, Epidemiology, and End Results (SEER) 18 databases, and evaluated data on more than 108,000 women with DCIS, a diagnosis that means abnormal cells were found in the milk ducts of the breast. The average age at diagnosis was just under 54 years old. The death rate due to breast cancer was 3.3% after 20 years and 1.1% after 10 years, according to the study. The risk of dying of breast cancer for a woman with DCIS is 1.8 times higher than someone in the general population of women, according to the study.
At 20 years after diagnosis, the death rate for women who were younger than 35 when diagnosed was 7.8% compared to 3.2% for older women, and 7% for black women compared with 3% for non-Hispanic white women.
The most important finding was that preventing a recurrence of cancer in the same breast did not prevent death from breast cancer. Among all patients, the risk of invasive recurrence on the same at 20 years was 5.9% and the risk of invasive recurrence in the other breast was 6.2%, which is about the same.
However, the study found that 517 women died of breast cancer after a diagnosis of DCIS but never had an invasive cancer in their breast before they died. In other words, the cancer spread outside of the breast but not within it.