Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Carcinoid Tumors Of The Lung

What Is It?

Carcinoid tumors have been called "cancers in slow motion" because they grow slowly and are less likely than other tumors to spread (metastasize) to other parts of the body.

Most carcinoid tumors start in the small intestine, but about 25 percent begin in the lungs. Carcinoid tumors tend to occur near the center of the lungs. They make up only 1 percent to 3 percent of all lung cancers. Some carcinoid tumors produce hormones that can cause a number of symptoms, but carcinoid tumors in the lung are much less likely to do so.

There are two types of carcinoid tumors of the lung: typical and atypical. Typical carcinoid tumors are about nine times more common than atypical carcinoid tumors, and are less likely to spread beyond the lungs.

Carcinoid tumors of the lung occur equally in women and men, and appear mostly in people ages 45 to 55.