Content Summary : The information in this booklet is based on CancerCare Connect ® Telephone Education Workshops conducted in partnership with the American Cancer Society, American Society of Clinical Oncology, Association of Clinicians for the Underserved, Association of Oncology Social Work, Intercultural Cancer Council, Lung Cancer Alliance, Multinational Association of Supportive Care in Cancer, National Center for Frontier Communities, National Lung Cancer Partnership (formerly Women Against Lung Cancer), and The Wellness Community. Types of Lung Cancer Doctors determine the type of lung cancer by looking at a biopsy of tumor cells under the microscope. It’s important to know the specific type because it helps doctors recommend the best treatment. There are two major types of lung cancer: Non-small cell lung cancer accounts for about 85 percent of lung cancers. Among them are these types of tumors: ■ Adenocarcinoma is the most common form of lung cancer in the United States among both men and women. Bronchioalveolar carcinoma , or BAC, is a less common 3 LUNG CANCER type of adenocarcinoma. It forms near the lungs’ air sacs. ■ Epidermoid carcinoma (also called squamous cell carcinoma) forms in the lining of the bronchial tubes . ■ Large cell carcinomas This name refers to non-small cell lung cancers that are neither adenocarcinomas nor epidermoid cancers. Small cell lung cancer accounts for about 15 percent of lung cancers in the United States. As a rule, small cell lung cancer has spread—at least in tiny amounts—by the time doctors find it.