About one fourth of all people with lung cancer have no symptoms when the cancer is diagnosed. These cancers are usually identified incidentally when a chest X-ray is performed for another reason. The other three-fourths of people develop some symptoms. The symptoms are due to direct effects of the primary tumor; to effects of cancer spread to other parts of the body (metastases); or to disturbances of hormones, blood, or other systems.
Symptoms of lung cancer include cough, coughing up blood or rusty-colored phlegm, fatigue, unexplained weight loss, recurrent respiratory infections, hoarseness, new wheezing, and shortness of breath.

  • A new cough in a smoker or a former smoker should raise concern for lung cancer.
  • A cough that does not go away or gets worse over time should be evaluated by a health care provider.
  • Coughing up blood (hemoptysis) occurs in a significant number of people who have lung cancer. Any amount of coughed-up bloodshould be evaluated by a health care provider.
  • Pain in the chest area is a symptom in about one fourth of people with lung cancer. The pain is dull, aching, and persistent.
  • Shortness of breath usually results from a blockage in part of the lung, collection of fluid around the lung (pleural effusion), or the spread of tumor through the lungs.
  • Wheezing or hoarseness may signal blockage or inflammation in thelungs that may go along with cancer.
  • Repeated respiratory infections, such as bronchitis or pneumonia, can be a sign of lung cancer.

Symptoms of metastatic cancer depend on the extent and location of the cancer spread.

  • Lung cancer most often spreads to the liver, the bones, and the brain.
  • Metastatic lung cancer in the liver may cause yellowing of the skinand eyes (jaundice), but it may not cause any noticeable symptoms at the time of diagnosis.
  • Lung cancer that has metastasized to the bone causes bone pain, usually in the bones of the spine (vertebrae), the thigh bones, and the ribs.
  • Lung cancer that spreads to the brain can cause difficulties with headaches, vision, weakness on one side of the body, and/orseizures.

Paraneoplastic syndromes are the remote, indirect effects of cancer not related to direct invasion. Symptoms include the following:

  • New bone formation (particularly in the fingertips) that can be painful
  • High levels of calcium in the blood
  • Blood clots
  • Low sodium levels in the blood

What are the types of lung cancer?

Lung cancers, also known as bronchogenic carcinomas (“carcinoma” is another term for cancer), are broadly classified into two types: small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). This classification is based upon the microscopic appearance of the tumor cells. These two types of cancers grow, spread, and are treated in different ways, so a distinction between these two types is important.

SCLC comprises about 10%-15% of lung cancers. This type of lung cancer is the most aggressive and rapidly growing of all the types. SCLC is strongly related to cigarette smoking. SCLCs metastasize rapidly to many sites within the body and are most often discovered after they have spread extensively.

NSCLC is the most common lung cancer, accounting for about 85% of all cases. NSCLC has three main types designated by the type of cells found in the tumor. They are:

  • Adenocarcinomas are the most common type of NSCLC in the U.S. and comprise up to 40% of lung cancer cases. While adenocarcinomas are associated with smoking like other lung cancers, this type is also seen in non-smokers — especially women — who develop lung cancer. Most adenocarcinomas arise in the outer, or peripheral, areas of the lungs. They also have a tendency to spread to the lymph nodes and beyond. Adenocarcinoma in situ (previously called bronchioloalveolar carcinoma) is a subtype of adenocarcinoma that frequently develops at multiple sites in the lungs and spreads along the preexisting alveolar walls. It may also look like pneumonia on a chest X-ray. It is increasing in frequency and is more common in women. People with this type of lung cancer tend to have a better prognosis than those with other types of lung cancer.
  • Squamous cell carcinomas were formerly more common than adenocarcinomas; today, they account for about 25% to 30% of all lung cancer cases. Also known as epidermoid carcinomas, squamous cell cancers arise most frequently in the central chest area in the bronchi. This type of lung cancer most often stays within the lung, spreads to lymph nodes, and grows quite large, forming a cavity.
  • Large cell carcinomas, sometimes referred to as undifferentiated carcinomas, are the least common type of NSCLC, accounting for 10%-15% of all lung cancers. This type of cancer has a high tendency to spread to the lymph nodes and distant sites.