Stages of Breast Cancer

You may have heard someone talk about their cancer in stages. This is the level of progression to which the cancer has spread. The stage of the cancer at detection often determines the treatment.

In breast cancer, the stage is based on the size and location of the primary tumor, the spread of the cancer, the tumor grade and whether certain biomarkers are present, the National Cancer Institute says. After you receive your diagnosis of breast cancer, doctors will perform tests such as biopsies, X-rays and various scans to see how far it’s spread.

Cancer can spread through tissue by growing into nearby areas, through the lymphatic system by spreading through lymph vessels to other parts of the body or through the blood. When cancer spreads to another part of the body, it’s called metastasis.

The metastatic tumor is the same kind of cancer as the primary tumor. If breast cancer spreads to the bones, it’s metastatic breast cancer, not bone cancer.

There are three types of breast cancer stage groups. The clinical prognostic stage is the first stage for all patients based on health history, physical exam, imaging tests and biopsies. Mammography or ultrasounds can be used to check the lymph nodes for signs of cancer. In the pathological prognostic stage, patients have surgery as their first treatment. It’s based on clinical information, biomarker status and lab results. The anatomic stage is based on the size and spread of the cancer. It’s used in parts of the world where biomarker testing is not available, which doesn’t include the United States.

The TNM system — tumor, lymph node, metastatis — is used to describe cancers, including breast cancer. T values refer to the size of the tumor and range from TX, meaning the tumor can’t be assessed, to T4, meaning the tumor has grown into the skin or chest wall or is inflammatory. N values refer to the size and location of lymph nodes where the cancer has spread. When the lymph nodes are checked using mammography or ultrasound, it’s called clinical staging. M values show if the cancer has spread to other parts of the body. M0 means it hasn’t; M1 means it has. Breast cancer most often spreads to the bones, lungs, liver or brain.

This system, along with grading that describes how quickly the tumor is likely to grow and spread, and biomarker testing is used to determine the breast cancer stage and the treatment of the cancer. Your doctor will be able to explain how your cancer was staged and discuss treatment options going forward.