Many cancer terms are used casually in the media or by doctors and nurses, but patients don’t always know exactly what the words mean. And some words have different meanings when used to describe cancer than they do in everyday use. You’ve probably heard most of the cancer-related terms below, but the precise meanings of some may surprise you.
Benign means not cancerous. Benign tumors have abnormal cells that cause the tumors to grow locally without spreading to other parts of the body. However, benign tumors are not always harmless; some can grow quickly and damage nearby tissue.
Malignant means cancerous. Malignant cells (cancer cells) are abnormal cells that can invade nearby tissue and spread throughout the body.
Neoplasm is another word for tumor. It refers to any new, abnormal tissue with uncontrolled growth. Neoplasms can be benign or malignant.
Major types of cancer
Carcinoma is any cancer that begins in the epithelial cells, which make up the outer layer of skin and the lining of organs and blood vessels. Carcinomas are the most common types of cancer, accounting for most breast, lung, kidney, thyroid, colon, prostate, stomach, and skin cancers. The risk of carcinoma increases with age, so these cancers mostly affect people 50 years and older.
Sarcoma is any cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. The two main types are soft tissue sarcomas and bone sarcomas. According to the Sarcoma Foundation of America, sarcomas represent only 1% of cancers in adults but 15% of cancers in children. Sarcomas can originate anywhere in the body, and they often grow deep within the tissues of the arms, legs, or torso.
Melanoma is a cancer that develops in melanocytes, which are pigment-producing cells in the skin and other organs. Although melanoma can occur in the eyes or mouth, most melanomas develop on the skin as a result of overexposure to sunlight. Melanoma is the most common type of cancer in people 25–29 years old.
Lymphoma is a group of blood cancers that begin in the lymphatic system, which is the network of vessels, organs, and tissues that filter the blood and produce many of the white blood cells (lymphocytes) that fight infection. Lymphomas may be described as B cell or T cell lymphomas, according to the type of blood cell that is affected; or as Hodgkin or non-Hodgkin lymphomas, according to the genetic mutation found in the lymphoma cells. Lymphomas can occur at any age and account for about 8% of childhood cancers.
Leukemia is a group of cancers that begin in the bone marrow tissues that produce blood; these cancers cause the production of abnormal blood cells that crowd out healthy blood cells. Leukemias are classified as acute or chronic and lymphoblastic or myelogenous. In acute leukemias, a large number of immature blood cells (blasts) are produced quickly; these leukemias progress rapidly. In chronic leukemias, most of the abnormal cells are more mature and are not produced as quickly. Lymphoblastic (also called lymphocytic) leukemias affect white blood cells (usually B cells), whereas myelogenous (also called myeloid) leukemias mainly affect red blood cells. Leukemias can occur at any age and account for about 30% of childhood cancers. In fact, acute lymphoblastic leukemia is the most common type of cancer in children.
Myeloma (also called multiple myeloma) is a rare cancer of the plasma cells in the bone marrow that impairs the plasma cells’ ability to produce antibodies, which fight infection. Myeloma weakens the immune system, can damage the bone structure itself, and can interfere with the production of normal blood cells. Myeloma usually affects people 60 years or older.
Terms related to cancer stage
Stage refers to the extent of a patient’s cancer. Different staging systems are used for different cancer types, but generally cancer stage depends on the tumor’s size and whether the cancer has spread to nearby lymph nodes or to distant parts of the body. A small cancer caught before it has spread is often classified as stage I; a cancer that has spread from its initial site to other parts of the body is usually stage IV.
In situ describes early-stage cancer that has not spread to adjacent tissues.
Invasive refers to cancer that has spread from its original location to adjacent tissues.
Metastasis is the spread of cancer cells from the original tumor to other parts of the body, where the cancer cells form new tumors (metastases).
Knowing these and other cancer-related terms can give cancer patients—and their family members and friends—a better understanding of the disease. Definitions of other words related to cancer and its treatment are provided by the National Cancer Institute at www.cancer.gov/publications/dictionaries/cancer-terms.
– C. Graber
For more information, ask your doctor, call askMD Anderson at 877-632-6789, or visit mdanderson.org.
OncoLog, February 2016, Volume 61, Issue 2