Invasive versus non-invasive breast cancer
While breast cancer is referred to as one disease, there are different forms of breast cancer, including invasive and non-invasive types.
A breast tumor sometimes grows slowly, and may have been growing for up to 10 years before it is large enough to be felt during a breast exam. Other types of breast cancers are very aggressive and can grow much faster.6
When abnormal cells grow inside the milk ducts, but have not spread to other areas, the condition is called ductal carcinoma in situ (DCIS). DCIS is a non-invasive breast cancer that can develop into invasive cancer. About 1 in 5 new breast cancer cases will be DCIS7. The earlier breast cancer is caught, the better chance a person has of surviving five years after being diagnosed. For breast cancer, 60.8% are diagnosed at the local stage. The 5-year survival for localized breast cancer is 98.5%.8
Invasive breast cancer occurs when abnormal cells from inside the milk ducts or glands break out into nearby breast tissue. Cancer cells can travel from the breast to other parts of the body through the blood stream or the lymphatic system. Lymph nodes are small, bean-shaped organs that are part of the bodies’ immune system and are important in fighting infections. The lymph nodes in the underarm area (axillary lymph nodes) are the first place breast cancer is likely to spread, or metastasize, to other parts of the body.
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Genetic breast cancer risk factors
Genetic mutations – Inherited genetic mutations (abnormalities) account for only an estimated 5-10 percent9 of all breast cancers diagnosed in the US and are considered rare in the general population.
- BRCA1 and BRCA2: The most common inherited mutations are the BRCA1 and BRCA2 genes.10 A woman with a mutated copy inherited from a parent has a higher risk of developing breast cancer during her lifetime. Ask your doctor if genetic testing would be right for you.
Personal history of breast disease – Women who have had breast cancer are at increased risk of developing a new cancer (this is different than return of a prior cancer).
Dense breast tissue – Women with dense breasts may have a 4-6 times greater chance of developing breast cancer than women with fatty breast tissue. Breast density is a way to describe the composition of a woman's breasts. Some women have more fat than breast tissue while others have more breast tissue than fat. When there is more breast tissue than fat, the breast is considered dense. It is estimated that more than 40 percent of women in the U.S. have dense breast tissue.
>> Download an infographic about breast cancer awareness and risks.
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