Lung cancer is cancer that starts in the cells that make up the lungs. Many other types of cancer, such as breast or kidney cancer, can spread to the lungs. When this happens, the cancer is not called lung cancer. This is because cancer is named for–and treatment is based on–the site of the original tumor.

When lung cancer begins to spread to other parts of the body, it is then referred to as metastatic lung cancer.

Stage 1: Slow-growing or noncancerous. Stage 1 cancer cells appear similar to healthy cells, and can usually be cured with surgery.

Stage 2: Malignant but slow-growing. Stage 2 cells under a microscope look slightly abnormal. These tumors have the ability to spread to nearby tissues or come back after initial treatment.

Stage 3: Malignant and more quick-growing. When viewed at the microscopic level, the malignant cells show even more severe abnormalities. Can easily generate abnormal cells which can spread to other parts of the lungs.

Stage 4: Develops rapidly and has various abnormal microscopic features. Stage 4’s timeline is aggressive, and the tumors can spread to other regions of the body.

Immunotherapy is a form of lung cancer treatment that makes use of chemical medications to jump start your own immune system to recognize and destroy cancer cells. 

In a UCLA study, treatment with the immunotherapy drug Pembrolizumab helped over 15 percent of patients with advanced non-small cell lung cancer live for at least five years.