Lung Cancer

Lung cancer occurs when cells begin to multiply too quickly in your lungs, causing the formation of tumors. It typically forms in the airways and air sacs and can spread to other parts of the body. Lung cancer is the second most frequently diagnosed cancer after breast cancer, accounting for more than 2.2 million new cases in 2020 and around 11% of all new cancer diagnoses worldwide.

Lung cancer is often hard to catch in the early stages and is the leading cause of cancer deaths worldwide.¹⁰

Smoking is the greatest risk factor for lung cancer and is linked to 80% of lung cancer deaths.^{2 4} Smoking risks are cumulative, meaning the more and the longer you smoke, the greater your risk. All types of smoking—cigarette, cigar, and pipe—increase your risk factor. If you don't smoke, secondhand smoke can still increase your risk of developing lung cancer.⁶

However, many people with no exposure to smoking can be at risk of lung cancer. Air pollution or exposure to hazardous materials such as radon, radioactive ores, and inhaled chemicals can cause lung cancer. In some parts of the world, arsenic may be present in drinking water, heightening lung cancer risks. If you have previously had lung cancer, or you have a family history of lung cancer, you are more likely to develop lung cancer.^{1 4}

If you are at higher risk for lung cancer, your doctor might order regular screenings to detect abnormalities in the lungs. Regular screenings can help to identify cancer before symptoms start, improving the likelihood of effective treatment.^{1 2}

It’s important to discuss your lung cancer risk with your physician, especially if you smoke, previously smoked, or have a family history of lung cancer. If you know of any exposure to hazardous materials that can cause lung cancer, you can also share this information with your medical team.

If your doctor suspects you have lung cancer, they will do a physical exam and discuss your symptoms. They may order imaging tests of your chest, blood and mucus tests, and a lung biopsy. If these tests come back positive for lung cancer, your medical team will conduct further tests to determine the stage of the cancer, including whether it has spread beyond the lungs. This information will help your care team determine an appropriate course of treatment.^{4 6}

Non-small cell lung cancer is more common, accounting for approximately 85% of all lung cancers. It also typically develops more slowly. Small cell lung cancer is aggressive, tends to spread quickly, and is often detected after it has migrated to other parts of the body. It is also harder to treat and may be more likely to recur.^{6 11}

Lung cancer staging is based on the size and position of the main tumor and the spread of the cancer to other parts of the body. Staging typically differs between SCLC and NSCLC, partially because SCLC is rarely caught in early stages.^{6 8}

Small Cell Lung Cancer

• Limited Stage – Cancer cells are generally still in the area where the cancer formed. They may have spread to local areas like the space between the lungs or to nearby lymph nodes.
• Extensive Stage – Cancer has spread beyond both the lungs and local areas to other parts of the body.

Non-Small Cell Lung Cancer

• Stage 0 – Cancer cells are present but have not penetrated beyond the top layer of cells within the air passages (bronchi and bronchioles) or to other parts of the body.
• Stage I – Tumor has begun to penetrate the deeper lung tissues but remains small and has not spread beyond the lungs.
• Stage II – Tumor has grown and become more deeply embedded within the lung structure. It may have spread to nearby lymph nodes.
• Stage III – Tumor continues to grow within the lung and may have expanded into the chest area. It may have spread to multiple lymph nodes, including lymph nodes farther from the main tumor, but has not spread to distant parts of the body.
• Stage IV – Cancer cells have metastasized to distant parts of the body.

Side effects depend on the course of treatment. Fatigue, nausea, and vomiting are common. Chemotherapy patients may experience hair loss, diarrhea, or loss of sensation. Immunotherapy can cause diarrhea, along with rashes, and joint pain, while radiation therapy can cause coughing, difficulty swallowing, and shortness of breath. Talk to your provider about options for managing pain or other symptoms.² There may be other side effects depending on the treatment, please consult your provider.

Prognosis will depend on many factors, including the stage of diagnosis, the type and staging of the lung cancer, how well it responds to treatment, and your overall health and age. Lung cancer that remains localized when treatment begins is associated with better relative five-year survival rates.^{2 12}

If lung cancer is no longer detected within your body, your healthcare team will continue to check to make sure the cancer has not returned, manage any side effects, and monitor your overall health.

This plan may include regular physical examinations and/or medical tests to monitor your recovery for the coming months and years. They will also watch for recurrence or second cancer.

Cancer recurs because small areas of cancer cells may remain undetected in the body. Over time, these cells may increase in number until they show up on test results or cause signs or symptoms. During follow-up care, a doctor familiar with your medical history can give you personalized information about your risk of recurrence.³

Researchers are continuously investigating potential new and more effective treatments. For guidance on the best treatment options for you—and to determine if you may qualify for a clinical trial—please speak with your healthcare provider.