What Is It?
Squamous cell carcinoma of the lung is a type of lung cancer. It occurs when abnormal lung cells multiply out of control and form a tumor. Eventually, tumor cells can spread (metastasize) to other parts of the body including:
In general, there are two categories of lung cancer: small cell lung cancer and non-small cell lung cancer. The cancer cells in each type look different under the microscope. They are also treated differently. The prognosis for non-small cell lung cancer tends to be better than for small cell lung cancer. Non-small cell lung cancers are more likely to be contained in one area, making treatment more likely to be successful.
Squamous cell carcinoma is one type of non-small cell lung cancer. The others are:
Adenocarcinoma is the most common type of lung cancer. Squamous cell carcinoma is the second-most common type. It accounts for about 30% of all cases of non-small cell lung caner.
Your risk of all types of lung cancer, including squamous cell carcinoma, increase if you:
Most cases of squamous cell carcinoma start in the center of the lungs. These tumors may cause some symptoms, such as coughing up blood, at an earlier stage than tumors on the edges of the lungs, such as adenocarcinomas.
Squamous cell carcinoma often spreads (metastasizes) to other parts of the body because of the constant flow of fluids (blood and lymph) through the lungs. The fluids can carry cancer cells to nearby areas, such as the chest wall, neck, esophagus and the protective sac around the heart. Unless it is diagnosed and treated early, it often spreads throughout the body.
Many lung cancers have the ability to secrete chemicals that circulate in the bloodstream. These chemicals can change the way the body functions. Squamous cell lung cancer may secrete a substance that leads to abnormal calcium levels. This can cause kidney problems.
Early on, squamous cell lung cancer may have no symptoms. If symptoms occur, they may include:
If the cancer has spread beyond the lungs, it can cause other symptoms. For example, you may have bone pain if it has spread to your bones, or headaches and seizures if it has spread to your brain.
Many of these symptoms can be caused by other conditions. See your doctor if you have symptoms so that the problem can be diagnosed and properly treated.
Your doctor may suspect lung cancer based on:
To look for evidence of cancer, your doctor will examine you, paying special attention to your lungs and chest. He or she will order imaging tests to check your lungs for masses. In most cases, a chest X-ray will be done first. If the X-ray shows anything suspicious, a computed tomography (CT) scan will be done. As the scanner moves around you, it takes many pictures. A computer then combines the images. This creates a more detailed image of the lungs, allowing doctors to confirm the size and location of a mass or tumor.
You may also have a magnetic resonance imaging (MRI) scan or a positron emission tomography (PET) scan. MRI scans provide detailed pictures of the body's organs, but they use radio waves and magnets to create the images, not X-rays. PET scans look at the function of tissue rather than anatomy. Lung cancer tends to show intense metabolic activity on a PET scan. Some medical centers offer combined PET-CT scanning.
If cancer is suspected based on these images, more tests will be done to make the diagnosis, determine the type of cancer and see if it has spread. These tests may include the following:
Occasionally, surgery is done to remove the tumor first. The diagnosis is made after the tumor has been examined in a laboratory.
Some studies have examined the use of CT scanning to try to diagnose lung cancers earlier. Although CT can detect abnormalities in the lungs before they cause symptoms, the abnormalities are not always cancer. In addition, studies have not shown that this type lung cancer screening improves patients' prognosis or survival.
After the cancer has been diagnosed, it is assigned a "stage." The stages of squamous cell carcinoma reflect the tumor's size and how far the cancer has spread. Stages I through III are further divided into A and B categories.
Squamous cell lung cancer will continue to grow until it is treated. As with any cancer, even if it seems to be cured after treatment, this lung cancer can return.
To reduce your risk of squamous cell lung cancer:
Treatment depends on the cancer's stage as well as the patient's condition, lung function and other factors. (Some patients may have other lung conditions, such as emphysema or chronic obstructive pulmonary disease [COPD].) If the cancer has not spread, surgery is usually the treatment of choice. There are three types of surgery:
Lymph nodes are also removed and examined to see if the cancer has spread.
Some surgeons use video-assisted thoracoscopy (VATS) to remove small, early-stage tumors, especially if the tumors are near the outer edge of the lung(VATS can also be used to diagnose lung cancer.) Because the incisions for VATS are small, this technique is less invasive than a traditional "open" procedure.
Because surgery will remove part or all of a lung, breathing may be more difficult afterward, especially in patients with other lung conditions(emphysema, for example). Doctors can test lung function prior to surgery and predict how it might be affected by surgery.
Depending on how far the cancer has spread, treatment may include chemotherapy (the use of anticancer drugs) and radiation therapy. These may be given before and/or after surgery. Unfortunately, squamous cell carcinoma does not respond to chemotherapy and radiation therapy as well as other types of tumors.
When the tumor has spread significantly, chemotherapy may be recommended to slow its growth, even if it cannot cure the disease. Chemotherapy has been shown to ease symptoms and prolong life in cases of advanced lung cancer. Radiation therapy can relieve symptoms, too. It is often used to treat lung cancer that has spread to the brain or bones and is causing pain. It can also be used alone or with chemotherapy to treat the lung cancer that is confined to the chest.
People who may not withstand surgery due to other serious medical problems may receive radiation therapy, with or without chemotherapy, to shrink the tumor.
In specialized cancer centers, cancerous tissue may be tested for specific genetic abnormalities (mutations). Doctors may then be able to treat the cancer with a "targeted therapy." These therapies can derail the cancer's growth by preventing or changing chemical reactions linked to particular mutations. For example, some target therapies prevent cancer cells from receiving chemical "messages" telling them to grow.
Knowing about specific genetic mutations can help predict which therapy will be best. This strategy can be especially helpful in certain patients, such as women with adenocarcinoma of the lung who have never smoked.
Even after treatment has been completed, lung cancer patients must return for regular follow-up appointments. Even if the cancer was initially "cured," it can return months or even years later.
When To Call a Professional
If you have any of symptoms of squamous cell lung cancer, see your doctor as soon as possible.
Squamous cell lung cancer usually is diagnosed after the disease has spread. The overall prognosis for squamous cell lung cancer is poor. Only about 16% of patients survive 5 years or longer. The survival rate is higher if the disease is detected and treated early.
Even when surgery and other therapies are initially successful, squamous cell lung cancer can return. This is because cancer cells can start to spread without being detected right away.
National Cancer Institute (NCI)
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American Cancer Society (ACS)
American Lung Association
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U.S. Department of Labor's Occupational Safety and Health Administration (OSHA)
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