Carcinoma and carcinoid are both words that relate to cancer, and while they share a common etymological origin they have different meanings. Carcinoma means "malignant tumor" and is defined as any cancer that arises on the skin or on a tissue covering an organ in the body. Carcinoid refers to tumors that arise from within the body and these can be either malignant—cancerous— or benign.
Carcinoid tumors originate within cells in the nueroendicrine system and are most commonly found in the gastrointestinal tract. The tumors are often small and slow growing. It can take many years for these tumors to grow to a size at which they are noticeable or produce symptoms.
Carcinoma is the word used to describe all cancer that originates on the skin or upon the covering on a body organ. Examples of types of carcinoma include basal cell carcinoma—the most common type of skin cancer—breast cancer, colon cancer, liver cancer, lung cancer, prostrate cancer and stomach cancer. These cancers usually are quicker to develop than carcinoids.
Almost all carcinoid sufferers report symptoms of flushing and diarrhea, and half report cramping and heart valve lesions. Carcinoma cancers may have a variety of symptoms, most usually a lump under the skin. Other symptoms may include skin discolorations and pain.
Treatments for carcinoma and carcinoid cancers are similar. Treatments may include chemotherapy, radiation therapy, surgery, hormone therapy, interventional surgery and stem cell transplants.
Some carcinoma cancers can be prevented, such as skin cancer, by limiting exposure to the sun. Others, such as colon cancer, have been shown to have reduced likelihood of occurrence based on certain diets—such as fiber, or a "Mediterranean diet." Still others, such as lung cancer, may be prevented by limiting exposure to harmful chemicals.
According to carcinoid.org, no empirical evidence has been found to suggest that carcinoid cancers may be prevented by diet.