Breast Health Information What is Breast Cancer? Key Statistics Risk Factors Risk Reduction Survival Rates

A malignant tumor is cancerous. Cells in malignant tumors can penetrate and destroy healthy body tissues. Cancer cells can also break away from tumors and travel, or metastasize, to other parts of the body through the bloodstream or lymph system. In this manner, cancer can spread and form secondary tumors in other parts of the body.

A benign tumor is an abnormal growth that is not cancerous and does not spread to other sites in the body. Benign tumors can usually be removed and in most cases do not recur. In almost all instances, benign tumors are not life threatening.

Breast cancer refers to a malignant tumor that has developed from breast cells. Most cancers are classified according to the part of the body in which the cancer began, even if the cancer has metastasized to other parts of the body; therefore, if a cancer that develops in the breast spreads to the lung or another body part, it is still referred to as breast cancer or metastatic breast cancer.

There are two general categories of breast cancer: noninvasive, where the cancer cells are confined to the ducts (milk passages); and invasive, where the cancer cells have broken through the duct into the surrounding fatty and connective tissues. Within these categories, there are a number of unique cancer types, affecting different components of the breast.

For more detailed information about the various forms of breast cancer, please see Types of Breast Cancer.

This website provides general information only. A physician should be contacted if you need any medical advice or if medical decisions need to be made.