MCS Role of staging

Staging, or determining how far advanced breast cancer is, plays a key role in establishing the most effective course of treatment.

A cancer diagnosis can be overwhelming, and people who receive such news may be flooded with a wide range of emotions. When delivering such a diagnosis, doctors share vital information about their patients’ disease. Those details can go a long way toward easing patients’ concerns.

Staging is an important component of cancer treatment. The National Cancer Institute notes that stage refers to the extent of the cancer, including how large the tumor is and whether or not it has spread, or metastasized. Learning the stage of the cancer, which is typically expressed on a scale of 0 through IV, helps doctors understand how serious the cancer is and the patient’s chances of survival. Staging also is used to plan treatments and potentially identify clinical trials that may serve as treatment options.

The American Joint Committee on Cancer oversees the breast cancer staging system and utilizes the TNM system. notes that three clinical characteristics, referred to as “T, N, and M,” are used to calculate the stage of the cancer:

• the size of the tumor and whether or not is has grown into nearby tissue (T)

• whether the cancer is in the lymph nodes (N)

• whether the cancer has spread, or metastasized, into other parts of the body beyond the breast (M)

Additional characteristics were added to the AJCC’s TNM breast cancer staging system in 2018. Though this has made determining the stage of breast cancer more complex, notes that it’s also made staging more accurate. That improved accuracy increases the likelihood that doctors will choose the most effective treatment plan for their patients, which should ease those patients’ concerns as they begin treatment.

Staging is complex, and patients should know that staging alone does not dictate prognosis. The following breakdown, courtesy of the NCI, is a brief description of the five stages of cancer (stages O through IV). A more detailed description of breast cancer stages can be found at

• Stage 0: This is diagnosed when abnormal cells are present but have not spread to nearby tissue. Stage 0 is also called carcinoma in situ, or CIS. CIS is not cancer, but it may become cancer.

• Stages I through III: Cancer is present in these stages. The higher the number, the larger the tumor is and the more it has spread into nearby tissues.

• Stage IV: The cancer has spread into distant parts of the body.

Staging plays an important role in treating cancer. Recognizing the role of staging can help patients better understand their disease and the direction of their treatments. More information about staging is available at

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