Cancer is cells growing out of control.

There are many types of cancer. As with all cancers, affected cells in the body change and grow out of control.

Usually, the multiplying cancer cells form a lump called a tumor.

Not all tumors are cancerous. Tumors that are not cancerous are called benign tumors. Cells from benign tumors do not spread to other parts of the body.

Cancerous tumors are called malignant tumors. Sometimes malignant tumor cells can break away from the original, primary tumor and travel through the bloodstream or lymphatic system to other parts of the body. This process is called metastasis (pronounced muh-TASS-tuh-sis).

Cancer is usually named after the part of the body where it first develops: the primary site. Breast cancer begins in the breast tissue. If it spreads to the lungs, for example, it is still considered breast cancer, not lung cancer.

Normal Cells
Malignant Cells

Defining recurrence

Recurrence is the term used to describe the return of cancer following primary treatment, either at the same site as the original tumor or somewhere else in the body. Breast cancer can recur in the following ways: