What Is Lung Cancer?

Lung cancer is the number one cause of cancer deaths in both men and women. This type of cancer is believed to develop over many years and often starts in the lining of the bronchi, the airways that lead to the lungs. However, it can also begin in the bronchioles or alveoli areas of the lungs.

Lung cancer causes some cells in the lungs to grow out of control. These cells are called cancer cells. Cancer cells grow at a different rate than normal cells. Their size and shape are also not normal. Cancer cells can spread to other areas in the lungs. Or, they can travel to other parts of the body. When cancer cells grow together in one area, they form a tumor.

Most lung cancers are classified as carcinomas, meaning they begin in the lining or covering tissue of the organ. There are several types of lung cancer based on the type of cells affected and how the cancer spreads. Lung cancer is grouped into two categories:

Types of Lung Cancer

  • Non-small cell lung cancer (NSCLC): About 80 to 85 percent of lung cancer cases
  • Small cell lung cancer (SCLC): About 10 to 15 percent of lung cancer cases

Treatments for these kinds of cancer are very different.

Non-small cell lung cancer

Most cases of lung cancer are called non-small cell (NSCLC). There are a few different types of NSCLC. The most common forms of NSCLC include:

  • Adenocarcinoma: About 40 percent of lung cancers, occurring most often in current or former smokers, although also common in nonsmokers. Usually slow-growing.
  • Squamous cell carcinoma: About 25 to 30 percent of lung cancers, and often linked to a history of smoking, often found in the central parts of the lungs.
  • Large cell carcinoma: About 10 to 15 percent of lung cancer, with a tendency to grow quickly.

Small cell lung cancer

Small cell lung cancer (SCLC) is less common than non-small cell lung cancer. SCLC is sometimes called oat cell carcinoma, because the cancer cells are shaped like oats when viewed under a microscope. This type of lung cancer may grow and spread faster than NSCLC.

SCLC occurs most commonly in smokers, and typically forms in the bronchial tubes, creating large tumors that can spread (metastasize) throughout the body.

Northwestern Medicine Expertise in Lung Cancer

Northwestern Medicine offers comprehensive, compassionate care provided by multidisciplinary teams working together in advanced, patient-centric facilities. Your Northwestern Medicine lung cancer care team may include:

  • Thoracic surgeons
  • Medical oncologists
  • Radiation oncologists
  • Pulmonologists
  • Pathologists
  • Nutritionists
  • Palliative medicine clinicians
  • Social workers
  • Advanced practice nurses
  • Geneticists
  • Pulmonary rehabilitation therapists
  • Smoking cessation specialists

Battling cancer is a multistep journey that may require many visits. This is why Northwestern Medicine has treatment and support services throughout Chicago and the surrounding suburbs, giving patients easier access to the expertise they need, wherever they may need it.