Lung cancer can form in any part of the lungs. When lung tumors grow in the upper portion of the lung, above the first rib, they’re called Pancoast tumors, after Henry Pancoast, M.D., the radiologist who first described them in the early 1900s. They’re also sometimes referred to as superior sulcus tumors, based on the location where they’re found.

“Pancoast tumors are quite rare, accounting for only 3% to 5% of lung cancers,” says...