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A quick guide to cancer terms

If you or someone you love has been diagnosed with cancer, you may hear the doctor use complex medical terms you aren’t familiar with or don’t know the meaning of. Here, we explain some of the most common terms used to describe cancer so you can better communicate with physicians and have a clear understanding of the diagnosis and the outlook.

Carcinoma is a general term used to describe cancer that occurs in the skin or mucous membranes, also called epithelial tissue. Organs such as the colon and cervix are composed largely of this kind of tissue.

Carcinoma in situ, also called noninvasive cancer, is a very early form of cancer. It is a malignancy that has not yet invaded the surrounding healthy tissue and is therefore highly curable.

Invasive cancer, a more advanced malignancy, is cancer that has invaded or infiltrated the surrounding healthy tissue.

Metastasis is the spread of cancer from one part of the body to another—lung cancer that has spread to the liver, say, or bladder cancer that has spread to the kidneys.

Sarcoma is a general term used to describe cancer that occurs in “connective tissue” such as muscle or bone.

Staging is a classification system used to describe how far cancer has spread so that a decision can be made about how to treat it most effectively. Cancer of the cervix, for example, has five stages. In stage 0, the cancer is confined to the surface of the cervix. In stage I, it has penetrated deeper layers of tissue. In stage II, it has extended to the upper third of the vagina or the tissue around the uterus but not the wall of the pelvis. In stage III, it has spread to the lower third of the vagina and/or the pelvic side-wall. In stage IV, the cancer has spread beyond the reproductive tract and has invaded distant organs, the bones or other systems of the body.

Of course, this is just a brief introduction to a complex subject, and we encourage you to learn more. Never be hesitant or embarrassed to ask the doctor to explain a term you don’t understand. Answering questions is part of every doctor’s job description. It’s also part of the team effort that we believe is so crucial to conquering cancer. The more you know about cancer, the better team member you’ll be—and the more power you’ll feel to fight the disease.