Just over one-quarter of a million people are expected to be diagnosed with lung cancer this year.

Though lung cancer is the second most common cancer in both men and women (not counting skin cancer) it is the leading cause of cancer death. Each year, more people die of lung cancer than of colon, breast, and prostate cancer combined, according to the American Cancer Society.

Approximately 80 – 85% of lung cancers are non-small cell lung cancer and 10 – 15% are small cell lung cancer. Smoking is a major risk factor – responsible for over 80% of all lung cancers – but a particularly strong risk factor for the development of small cell lung cancer. Exposure to second-hand smoke, radon, asbestos, and other hazardous chemicals also increase risk, as well as previous radiation therapy to the chest area.

The US Preventive Services Task Force recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years.

Symptoms and the results of imaging tests might suggest that a person has lung cancer, but the actual diagnosis is made by a pathologist looking at cells from sputum, or from a tissue biopsy of the suspicious area. Furthermore, biomarkers, or molecular characteristics, found in either blood or tumor tissue, are being identified and investigated as tools to help oncologists in treatment decision-making.

Small cell lung cancer (SCLC) is usually staged as either limited or extensive. Surgery may be recommended if there is limited cancer, but in most cases, SCLC has already spread by the time it is found. Chemotherapy is almost always recommended, and often concurrent radiation therapy. About one-half of people with SCLC will eventually have the cancer spread to the brain; prophylactic cranial irradiation may be recommended to prevent brain metastases.

The same drugs are often recommended for extensive stage SCLC, sometimes in combination with immunotherapy.

Early stage non-small cell lung cancer (NSCLC) can be treated by surgery alone or with radiation therapy. Adjuvant chemotherapy after surgery may lower the risk of recurrence, but biomarker research is ongoing to help oncologists determine which people are likely to be helped by chemotherapy.

Treatment for more advanced NSCLC that hasn’t yet metastasized may include some combination of radiation therapy, chemotherapy, and/or surgery.

Once NSCLC has spread to distant sites, treatment can include surgery, chemotherapy, targeted therapy, immunotherapy, and radiation therapy to both increase survival and relieve symptoms. Tumors will be tested for common gene mutations, such as EGFR, ALK, ROS1 and BRAF, to guide treatment. Tumors may also be evaluated for PD-L1 levels to guide decisions on immunotherapy treatment.