DCIS accounts for 1 of every 5 new breast cancer diagnoses. It's an uncontrolled growth of cells within the breast ducts. It’s noninvasive, meaning it hasn’t grown into the breast tissue outside of the ducts. The phrase "in situ" means "in its original place."
DCIS is the earliest stage at which breast cancer can be diagnosed. It's known as stage 0 breast cancer. The vast majority of women diagnosed with it are cured.
Even though it’s noninvasive, it can lead to invasive cancer. It's important that women with the disease receive medical treatment. Experts believe that up to 30% of women with DCIS will develop an invasive breast cancer within 10 years of the DCIS diagnosis. The invasive cancer usually develops in the same breast and in the same area as where the DCIS happened.
How is ductal carcinoma in situ diagnosed?
This type of cancer doesn’t usually cause a lump in the breast that can be felt. Symptoms of DCIS include breast pain and a bloody discharge from the nipple. About 80% of cases are found by mammograms. On the mammogram, it appears as a shadowy area.
If your mammogram suggests that you may have DCIS, your doctor should order a biopsy to analyze the cells and confirm the diagnosis. Biopsies for DCIS are typically done using needles to remove tissue samples from the breast.
If you have DCIS, your doctor may order more tests to gather information about your cancer. These tests may include an ultrasound or MRI. Based on the results of various tests, your doctor will be able to tell the size of your tumor and how much of your breast is affected by the cancer.
How is ductal carcinoma in situ treated?
No two patients are the same. Your doctor will customize your treatment plan based on your test results and medical history. Among other things, your doctor will consider:
Aggressiveness of the cancer cells
Your family history of breast cancer
Results of tests for a gene mutation that would increase the risk of breast cancer