There are many types of breast cancer, though some of them are very rare. The majority of breast cancers begin in the cells that line the ducts. Others begin in the lobules. A small number start in other tissues.
In this section, you will learn about in situ and invasive breast cancers. Occasionally a breast tumor may be a mix of these types.
In situ — which translates to “in place” in Latin — means that the abnormal cells tend to be confined to the type of tissue where they develop and may be less aggressive than invasive cancers.
Ductal carcinoma in situ (DCIS), also known as stage 0, intraductal, or pre-invasive breast cancer, is the most common form of in situ breast cancer. According to Stanford Medicine, it accounts for about 20% of all newly diagnosed breast cancers. Although DCIS tends not to spread outside the ducts of the mammary glands, about 50% of cases can develop into more invasive cancers if left untreated. However, the outlook is usually excellent for people who receive treatment for DCIS.
Biopsy is the removal and examination of tissue for the purpose of diagnosing disease.
Invasive breast cancers spread to multiple parts of the breast and can eventually travel to nearby lymph nodes. From there, the cancer may travel through blood and the lymphatic system to other parts of the body, such as the bones, liver, or lungs.
Watch a medical animation to see how invasive breast cancer develops.
Back to top
One million cancer deaths avoided since 1990s, group says
Actress has already had double mastectomy due to gene linked...
Study counters prior research suggesting the medicine might ...
Testing revealed she carries a genetic mutation that left he...
Scientists identify changes in estrogen metabolism as key fa...
We care about your feedback. Let us know how we can improve your CancerCompass experience.