Diseases & Conditions

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 most common malignancy worldwide, with more than 1 million cases diagnosed yearly, making it the leading cause of cancer death in both men and women. Of those people born today, one in 14 men and women will be diagnosed with cancer of the lungs and bronchus (large air tubes leading from the windpipe to the lungs) during their lifetime.

How is Lung Cancer Diagnosed and managed?

Usually, concern that a patient may have lung cancer starts when an abnormal finding is seen 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 tumour . 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 is present.

What are the Stages of lung Cancer?

Staging allows the physician to fully understand the extent of the patient's cancer to help make treatment decisions and determine 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. Lymph nodes act as a filtering system outside the lung, collecting cancer cells that are beginning to migrate out of the lung.
  • Distant: the cancer has spread (or metastasized) to other parts of the body.

What are the types of lung cancer?

About 90% of 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 edges 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 in which the cancer develops:

  1. Adenocarcinoma often starts growing near the outside surface 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 sItem #2
  3. Large cell carcinoma often starts near the surface 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 fairly 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 usually happens decades after exposure to asbestos.

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. The most critical factor in determining the survival rate is the stage at the time of diagnosis. Those that are diagnosed at a localised stage are curable. Unfortunately, most people are diagnosedwhen 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 helps explain why lung cancer has one of the poorest survival rates of all cancers. Two-year survival rate of those diagnosed with lung cancer is 25 percent. At five years, survival rate drops to 15 percent.

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 by pill.

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

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.

These therapies affect 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 & fatigue. Your health care providers can suggest ways to make any side effects more manageable and to help relieve 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 any 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 into or 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 is a dry, sore throat; difficulty swallowing; fatigue; skin changes at the site of treatment; and 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 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 some 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.

Types of surgery

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. All patients are considered first for minimally invasive surgery, although some complex cases may still require a traditional, open approach. Trained thoracic surgeons 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 large section of the lunge, (there are three lobes of the lung on the right and two on the left), is called 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.

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 in hopes of finding lung cancer at a stage that it can be cured. 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).

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