Breast Cancer: The Stage You're In Is Key

— -- While a diagnosis of breast cancer is almost always shocking, not all breast cancers behave in the same way.

In an effort to provide the best possible plan of attack, cancer specialists perform a series of tests to classify breast tumors into stages. This information determines the extent of the cancer and is used to guide treatment decisions.

While early-stage disease refers to those cancers that are still contained within the breast or have not spread very far, later-stage breast cancers may have advanced to other parts of the body.

Below, Dr. D. Lawrence Wickerham, associate chairman of the National Surgical Adjuvant Breast and Bowel Project, or NSABP, and an associate professor of human oncology at Drexel University College of Medicine in Pittsburgh, explains how staging is assessed and what it means in terms of long-term treatment planning.

What are the stages of breast cancer?Breast cancer stage is a method that we can use to describe how advanced a particular cancer is. The earliest invasive breast cancers are stage I, where the cancer is limited to the breast itself. Stage II is a little bit more advanced. It involves not only the breast, but some of the lymph nodes, primarily in the armpit. Stage III disease refers to larger cancers that are more advanced, but it isn't until stage IV, the most advanced stage, that the tumor spreads into other organs in the body.

Isn't there a stage earlier than stage I?Actually, the earliest stage is stage 0. Twenty years ago, these noninvasive breast cancers, which are cancers that haven't yet developed the biological ability to spread to other organs, were a rare event. It occurred in approximately 2 percent to 3 percent of the breast cancers detected every year.

Now, 20 percent to 25 percent of the women who develop breast cancer in the United States will have these noninvasive breast cancers. The most common type of noninvasive breast cancer is ductal carcinoma in situ, which we abbreviate as DCIS. Ductal carcinoma in situ means that under the microscope, the duct tissue within the breast itself has the appearance of a breast cancer, but it hasn't spread outside of the ducts, the tubes within the breast. So it is in place, or in situ.