Lung Cancer


What is lung cancer?

Like other cancers, lung cancer develops when normal processes of cell division and growth are disrupted, giving way to abnormal, uncontrollable growth. The cells grow into a mass, or tumor. Any abnormal growth in the body that directly invades surrounding tissues and organs, spreads to other parts of the body, or has the potential to grow back after being removed is called “malignant,” or cancerous.

Who gets lung cancer?

Lung cancer can take several years to develop. Cigarette smoking is the most common risk factor for developing lung cancer. Many people exposed to cigarette smoke – or some of its components – will end up with permanent abnormal changes in their lungs. These changes can cause a cancerous tumor to develop within the lung.

  • Twenty-five percent of all cases of lung cancer worldwide are diagnosed in people who have never smoked. The underlying cause in these cases is not well understood.
  • Two out of three people diagnosed with lung cancer are over age 65.
  • The most common age at diagnosis is 70 years.

How common is lung cancer?

Lung cancer is the second most common malignancy in the country, but it is the deadliest as it causes the highest number of deaths of all cancers. Lung cancer diagnoses are expected to be about 228,150 new cases in 2019 in the United States, while a predicted 142,670 deaths will occur in 2019.

What are the stages of lung cancer?

Staging allows the physician to fully understand the extent of the patient’s cancer to determine treatment decisions and predict expected outcomes. Doctors use specific terms to describe the stages of cancer, but a straightforward way of describing staging might be as follows:

  • Localized: The cancer is confined to the lung.
  • Regional: The cancer has spread to lymph nodes (or glands) within the chest.
  • Distant:The cancer has spread (or metastasized) to other parts of the body.

What are the types of lung cancer?

Most lung cancers start in the lining of the bronchi (air passageways branching off the trachea, or breathing tube). Lung cancer also can form in glands below the lining of the bronchi, frequently in the outer areas of the lungs. These lung cancers are one of two major types, small cell or non-small cell lung cancer, each of which grows and spreads different ways:

Non-small cell lung cancer

Non-small cell lung cancer is much more common, and usually grows and spreads more slowly than small cell lung cancer. There are three main types of non-small cell lung cancer, named for the type of cells from which the cancer develops:

  1. Adenocarcinoma often starts growing near the periphery of the lung and may vary in both size and growth rate. This is the most common type of lung cancer in both smokers and those who have never smoked.
  2. Squamous cell carcinoma usually starts in one of the larger breathing tubes near the center of the chest. The size of these lung tumors can range from very small to quite large.
  3. Large cell carcinoma often starts near the periphery of the lung, grows rapidly and is usually quite extensive when diagnosed.
Small cell lung cancer

Small cell lung cancer is less common than non-small cell lung cancer accounting for about 15 percent of all lung cancers. This type of lung cancer grows rapidly, is likely to be advanced by the time of diagnosis and spreads to other parts of the body quickly.

Rare cancers of the chest

There are more than a dozen kinds of uncommon tumors that can develop in the chest, which may or may not arise from the lung. Some of the less common types include carcinoid tumors (often located in a large airway), and malignant mesothelioma that develops from the pleura, or lining of the lung.


Mesothelioma is a cancer that affects the mesothelium, the protective membrane that covers most of the body’s internal organs. This rare cancer affects only about 3,000 people annually, usually in the part of the mesothelium surrounding the lungs (pleura) but sometimes in the pericardium that covers the heart. Mesothelioma typically happens decades after exposure to asbestos.

Symptoms and Causes

What are symptoms of lung cancer?

Signs and symptoms of lung cancer are not always present until the disease advances. However, some people do have symptoms early. These include:

  • Coughing that does not improve
  • Hoarseness
  • Blood in phlegm or sputum that is expelled by coughing
  • Weakness
  • Wheezing
  • Infections that return or will not clear
  • Chest pain that gets worse with cough or laugh

Advanced lung cancer symptoms include coughing, shortness of breath, chest pain, fatigue and/or unintentional weight loss. Signs and symptoms that might appear if the cancer has spread to other places include bone pain, headache, muscle weakness and/or eyelid drooping.

Diagnosis and Tests

How is lung cancer diagnosed and managed?

Usually, concern that a patient may have lung cancer starts as an abnormal finding on a chest imaging study (chest X-ray or CT scan) or when the disease is advanced enough to cause symptoms, such as coughing, shortness of breath, chest pain, fatigue and/or weight loss.

Diagnosis requires a biopsy, or the removal of cells or tissues from the suspicious mass. Biopsies can be performed through a camera fed through the breathing tubes (called bronchoscopy) or from a needle inserted through the skin into the lung tumor. If these approaches are not successful, surgery may be required for an adequate diagnosis. The biopsy is important in determining whether or not it is cancer, and to determine which type of lung cancer.

Clinical trials

For some patients, participating in a clinical trial may be a treatment choice. Clinical trials are done to find out if new cancer treatments are safe and effective, or to see if they are better than the standard treatment. Many of today’s standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a prospective new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and move medical knowledge forward.

Lung cancer screening

Lung cancer screening refers to testing a healthy individual at high risk for developing lung cancer who has no symptoms of lung cancer to find lung cancer at a stage that it can be better treated. Low-dose chest CT based screening has been found to reduce the number of people who die from lung cancer with acceptable risks when performed in a high quality setting. At Cleveland Clinic, we have a comprehensive lung cancer screening program for those individuals at high risk of developing lung cancer (aged 55 to 77, 30+ pack-years of smoking, smoked within the past 15 years).

Management and Treatment

How is lung cancer treated?

All relevant information about the patient, including his or her health status, the kind of tumor and how far it has spread are brought together to design the most appropriate therapy for that individual’s cancer.

Lung cancer is a very challenging cancer to treat. Cell type and stage are the most critical factors in determining the survival rate is the stage at the time of diagnosis. Those that are diagnosed at a localized stage may be curable. Unfortunately, most people are diagnosed when the disease has spread outside the chest (advanced or distant) or involves the nodes in the chest (regional). Also, the lungs are very sensitive organs and may not handle some forms of treatment easily. This combination explains why lung cancer has one of the poorest survival rates of all cancers. The overall two-year survival rate of those diagnosed with lung cancer is 25%. At five years, survival rate drops to 15%.

It is important to discuss the goals of lung cancer treatment with your doctor. Some treatments may be used to control the cancer. Others are used to improve quality of life and/or reduce symptoms. These treatments may be used alone or in combination.

Chemotherapy and targeted therapies

Chemotherapy is the use of drugs that are designed to kill rapidly growing cells, such as cancer cells. Chemotherapy may be injected directly into a vein (by IV, or intravenously) or given through a catheter, which is a thin tube placed into a large vein and kept there until it is no longer needed. Some chemotherapy drugs are taken orally in pill form.

Targeted agents are a newer class of drugs that are designed to act against specific weaknesses in cancer cells or surrounding supportive tissues, such as blood vessels. These drugs can also be taken orally or by IV. They are most effective in cancers with specific changes in their genes or cell receptors.

In early stages of non-small cell cancer, chemotherapy may be used in conjunction with surgery to improve survival rates. In more advanced stages of non-small cell cancer and in all stages of small cell cancer, chemotherapy and targeted therapies may be used to relieve symptoms and extend life.

Chemotherapy affects both normal cells and cancer cells. Your doctors will try to prevent side effects as much as possible while treating the cancer appropriately. Side effects depend largely on the specific type of drug and the amount given. They can be different for each person and may be only temporary. Common side effects of chemotherapy include nausea and vomiting, hair loss, mouth sores and/ or fatigue. Your healthcare providers can suggest ways to make any side effects manageable and to help improve symptoms that may occur during and after procedures.

Radiation therapy

Radiation therapy is a form of high energy X-ray that kills cancer cells. It can be used as a primary treatment, or in combination with chemotherapy (with or without surgery). It often can play an important role in advanced cancer patients by providing relief from pain, blockage of the airways, shortness of breath or coughing.

Radiation therapy is a “focused” treatment, meaning it is designed to maximize its effect on the cancer cells while minimizing injury to normal cells. Radiation to treat lung cancer most often comes from a machine (external radiation). Occasionally, the radiation may be delivered internally using tubes that place a radioactive seed directly near the tumor (internal radiation or brachytherapy).

Side effects of radiation therapy depend mainly on the part of the body that is treated and the treatment dose. Common side effects of radiation therapy to the chest are a dry, sore throat; difficulty swallowing; fatigue; skin changes at the site of treatment; and/or loss of appetite.

An area of particular innovation in radiation therapy is a high-technology approach, sometimes termed “radiosurgery.” In very select patients who have small tumors but for whom surgery is not desired or is unsafe, radiosurgery using very high doses of precisely focused radiation aimed only at the small tumor in the lung, is an effective alternative.


Surgery is still considered the “gold standard” for treating early-stage lung cancer. Removing the tumor and surrounding lung tissue gives the best chance for cure for patients whose disease is localized. Surgery should be performed by specialized thoracic surgeons with particular expertise in treatment of lung cancer and other chest malignancies. Your surgeon will determine whether a tumor is resectable (removable). Not all tumors are resectable due to their location near, or if they have invaded, vital structures.

In patients with multiple medical problems or poor lung function, surgery may not be the best option. This is carefully determined by our multidisciplinary team including pulmonologists, medical oncologists, and radiation oncologists who work collaboratively daily.

What types of surgery are used to treat lung cancer?

How much lung tissue will be removed and what type of surgical approach will be used depends on where the tumor is located in the lung, its size, patient’s body type/weight and any previous chest surgeries. When resection is needed, minimally invasive approaches are considered. Trained thoracic surgeons may perform video-assisted thoracic surgery (VATS) and VATS lobectomy routinely as well as robotic surgery. Surgical resection of lung cancer is generally performed as:

  • Limited resection: An operation to remove only a small portion of the lung is called a segmental or wedge resection.
  • Lobectomy: Removal of a defined section of the lung, (there are three lobes of the lung on the right and two on the left), is a lobectomy. This is the most common surgery performed for lung cancer.
  • Pneumonectomy: The removal of an entire lung is called a pneumonectomy.

Recovery after thoracic surgery depends on the extent of the surgery, whether or not it is performed minimally invasively, as well as the age and overall fitness of the patient. Many patients return home within three to four days after surgery. Patients who undergo minimally invasive surgery can generally return to work three weeks after surgery.

What other services are offered to people with lung cancer?

Pulmonary rehabilitation

Chronic diseases and disorders of the lungs and airways, as well as some of the invasive treatments for them, can take their toll on health and quality of life. Pulmonary rehabilitation programs use an array of tactics – from education and exercise to encouraging lifestyle changes – to help our patients manage their conditions.

Pain management

Pain can be a significant issue for people undergoing cancer treatment. Various cancer interventions, as well as the cancer itself, can cause pain. Effective pain management can help maintain or improve quality of life and reduce the risk of depression associated with pain.

Smoking cessation

Smoking is a major cause of lung cancer, but quitting can be a challenging proposition for some chronic smokers. As smoking patterns vary from person to person, there is no “best” method for quitting. The most successful smoking cessation programs offer smokers a range of strategies.


How can I prevent lung cancer?

There is no absolute way to prevent lung cancer. However, there are things that will lower your risk.

  • Do not smoke. If you do smoke, quit. Avoid breathing in smoke from people who do smoke.
  • Reduce your exposure to chemicals known to cause cancer, such as:
    • Arsenic
    • Asbestos
    • Beryllium
    • Cadmium
    • Substances containing nickel or chromium
    • Coal products
    • Air pollution, such as exhaust from diesel engines
    • Radon. Have your home tested for radon, a radioactive gas that has no color or odor.
  • Eat a healthy diet.
  • Exercise regularly.

Outlook / Prognosis

What is the outlook for people with lung cancer?

Your healthcare providers will help you understand what to expect after cancer treatment in terms of follow-up care, lifestyle changes, and making important health-related decisions.

If lung cancer is localized or regional and treatment has been administered with the intention of curing the cancer, follow-up testing will be performed to ensure the cancer does not recur. You also will be assessed for side effects related to the treatment received, and treatment will be offered to help with any related symptoms.

Follow-up in patients whose lung cancer is metastatic and/or treatment is intended to improve the quality of life and extend life. Tests done over time will determine how the cancer is responding to treatment, and to monitor for side effects from therapy. The length of treatment or the need to change therapies will be determined by these follow-up tests.

Last reviewed by a Cleveland Clinic medical professional on 07/10/2019.


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