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Cancer stages

Stage III cancer

Stage III cancer is a serious disease that requires expert care. At Cancer Treatment Centers of America® (CTCA), we use a variety of sophisticated tests and procedures to confirm the stage of your disease and develop a comprehensive treatment plan designed just for you.

Patients whose cancer has advanced to stage III may consider a second opinion to confirm their diagnosis and explore new treatment options. Chat with us to set up an appointment with one of our cancer experts.

What is Stage III cancer?

Stage III cancer is sometimes referred to as locally advanced cancer. In this stage, the tumor may have grown to a specific size, the cancer may consist of multiple tumors, and/or the cancer may have spread to adjacent lymph nodes, organs or tissue. In some cases, stage III cancers may be considered metastatic cancers, meaning they may have spread beyond their organ of origin.

Many stage III cancers have multiple subcategories, usually designated as stages IIIA, IIIB and IIIC. These subcategories are often determined by the size of the tumors, whether multiple tumors are present and the degree to which the cancer has spread locally.

Liquid cancers, or blood cancers, such as leukemia, lymphoma or multiple myeloma, are staged differently than most other cancers because they may not always form solid tumors. Liquid cancers may be staged by a variety of factors, including:

Stage III cancer is determined in the five most common cancers this way:

Stage III breast cancer

The tumor may also be quite large at this stage, possibly extending to the chest wall and/or the skin of the breast. Cancer cells may be found in nearby lymph nodes.

Learn more about breast cancer stages

Stage III lung cancer

The cancer has spread from the lungs to the lymph nodes and/or to nearby structures and organs, such as the heart, trachea and esophagus.

Learn more about lung cancer stages

Stage III prostate cancer

The cancer is in tissues near the prostate. It also may have reached the seminal vesicles, the glands that secrete components of semen.

Learn more about prostate cancer stages

Stage III colorectal cancer

The cancer has grown into the intestine wall and may have entered the muscle. The cancer may have spread to nearby lymph nodes and/or into nearby organs or tissues.

Learn more about colorectal cancer stages

Stage III melanoma

The cancer cells have spread to nearby lymph nodes, but not to distant organs.

Learn more about melanoma stages

Most cancers are staged using some form of the TNM system. Doctors may also use the TNM system to help determine the extent of certain cancers in each stage. The TNM system stands for:

Some cancers, especially liquid cancers, are staged using different established protocols. The Binet and Rai systems, for instance, are used to stage certain types of leukemia.

Cancers of the central nervous system (CNS are graded rather than staged. Grade III brain and spinal cancers are considered fast-growing and may have invaded nearby tissues.