Squamous cell carcinoma of the lungs is one form of non-small cell lung cancer. Non-small cell lung cancers account for about 80% of lung cancers, and of these, roughly 30% are squamous cell carcinomas.
Squamous Cell Carcinoma of the Lungs – An OverviewSquamous cell carcinoma begins in the tissue that lines the air passages in the lungs. It is also known as epidermoid carcinoma. Most squamous cell carcinomas of the lungs are located centrally, usually in the larger bronchi that join the trachea to the lung. Squamous cell carcinomas are linked more strongly with smoking than other forms of non-small cell lung cancers, and are more common in men than in women. They tend to be slow-growing, and due to their location are often found earlier than other forms of lung cancer.
The incidence of squamous cell carcinoma of the lungs has been decreasing in recent years, whereas another form of lung cancer, adenocarcinoma has been increasing. It is thought by some that the addition of filters to cigarettes allows smoke to be inhaled more deeply into the lungs where adenocarcinomas tend to occur.
SymptomsCommon symptoms of lung cancer include a persistent cough, coughing up blood, and wheezing. Since squamous cell carcinomas tend to be located near the large airways, they often cause symptoms earlier than other forms of lung cancer. Obstruction of the airway can lead to infections such as pneumonia, or collapse of part of a lung (atelectasis).
Squamous cell carcinoma is the most common cause of something known as pancoast syndrome or superior sulcus syndrome. Pancoast syndrome is caused by lung cancers that begin near the top of the lungs and invade structures nearby. Symptoms often include shoulder pain that radiates down the inside of the arm, weakness or prickly sensations in the hands, flushing or sweating on one side of the face, and a droopy eyelid (Horner’s syndrome).
Individuals with squamous cell carcinoma are also more likely to experience an elevated calcium level (hypercalcemia) which can result in muscle weakness and cramps. Hypercalcemia is one of the symptoms of paraneoplastic syndrome, and is caused by a tumor secreting a hormone-like substance that raises the calcium level in the blood.
DiagnosisSquamous cell carcinoma of the lungs is often first suspected when abnormalities are seen on an x-ray. Further evaluation may include:
- Chest CT Scan
- Sputum Cytology – Since squamous cell carcinomas often extend into the airway, a sample of sputum can sometimes detect cancer cells
- PET Scan - a test designed to look for actively growing tumors
- Endobronchial Ultrasound
Depending upon the results, your doctor will usually want to obtain a sample of tissue to confirm the diagnosis, and will order further tests to check to see if your cancer has spread.
StagingSquamous cell carcinoma of the lungs is broken down into 4 stages:
- Stage 1 – The cancer is localized within the lung and has not spread to any lymph nodes
- Stage 2 – The cancer has spread to lymph nodes or the lining of the lungs, or is in a certain area of the main bronchus
- Stage 3 – The cancer has spread to tissue near the lungs
- Stage 4 – The cancer has spread (metastasized) to another part of the body
Doctors also use another, more confusing way to decide upon the stage of a lung cancer. In this they look at the size of the tumor (represented by a T,) whether nodes are affected, where and how many (represented by an N,) and whether or not the tumor has spread (metastastized) to regions of the body oustide of the lungs, or to the other lung (represented by an M.) For example, your doctor may descibe your lung cancer as T3N2S0. This is explained further in the following article:
CausesSquamous cell carcinoma of the lung is strongly associated with smoking, but other causes can contribute as well.
- Overview of Lung Cancer Causes
- Environmental Causes of Lung Cancer
- Occupational Causes of Lung Cancer
- Genetics and Lung Cancer
TreatmentsDepending upon the stage of squamous cell carcinoma of the lungs, treatment may include surgery, chemotherapy, radiation therapy, or a combination of these. Many clinical trials are in progress looking for new ways to treat this cancer, and to help decide which treatments are most effective.
- cisplatin (Platinol) and gemcitabine (Gemzar). For those who respond to treatment, continuous (maintenance treatment) with erlotinib (Tarceva) or Alimta (permetrexed) may be used.
- brachytherapy) in which radioactive material is delivered to a precise area of the lungs during a bronchoscopy.
SubtypesSquamous cell lung cancers are further divided into 4 subtypes by what they look like under microscope and how they behave. These include:
- Secretory, and
PrognosisThe overall 5-year survival rate for lung cancer is sadly only about 15%. For early-stage disease, especially when surgery can remove the tumor, the survival rate is much higher.
CopingA diagnosis of squamous cell carcinoma of the lungs is frightening and you may feel very alone. Allow your loved ones to support you. Many people have no idea how to react towards someone who is diagnosed with cancer. Letting people know specific things they can do to help may ease their anxiety, as well as fill your need for extra support at this time. Ask questions. Consider joining a lung cancer support group either through your cancer center or online. Talking with others who have “been there” can make the world seem a little smaller.
- Finding a Lung Cancer Support Group
- Supporting a Loved One With Cancer
- Tips for Improving Lung Cancer Survival That Your Doctor Might Not Tell You
College of American Pathologists. Lung: Squamous Cell Carcinoma. Accessed 10/30/12. http://www.cap.org/apps/docs/reference/myBiopsy/LungSquamousCellCarcinoma.pdf
Sheth, S. Current and emerging therapies for patients with advanced non-small cell lung cancer. American Journal of Health-System Pharmacy. 2010. 67(1 Suppl 1):S9-14.
Wu, P. et al. Gene-expression data integration to squamous cell lung cancer reveals drug sensitivity. British Journal of Cancer. 2013 Sep 3. (Epub ahead of print)
Yasufuku, K. Early diagnosis of lung cancer. Clinics in Chest Medicine. 2010. 31(1):39-47.