Squamous cell lung carcinoma is a cancer that often has a connection to smoking. It starts in the cells lining the bronchi.
Squamous cell lung carcinoma begins in the top layer of cells, called squamous cells, that line the large airways (bronchi) of the lung. It usually grows in the bronchi that branch off of the main left or right bronchus in the center of the chest.
Types of squamous cell lung carcinoma
As of 2015, the World Health Organization (WHO) classifies three subtypes of squamous cell lung carcinoma. These are based on how the cancer cells appear under a microscope and include:
- keratinizing squamous cell carcinoma
- nonkeratinizing squamous cell carcinoma
- basaloid squamous cell carcinoma
Squamous cell lung carcinoma begins in the cells lining the bronchi. Over time, cancer can spread to nearby lymph nodes and organs and travel through the blood, or metastasizing, to other parts of the body.
Doctors use tumor size, location, and severity of spread to classify cancer into stages. Using the TNM system, the cancer is given a number indicating tumor size (T), spread to the lymph nodes (N), and metastasis (M). These are then combined to classify the cancer into a stage.
There are six main stages. Stages 1 to 4 are subdivided according to tumor size, number, and location:
Occult means hidden. There are cancer cells in the sputum or other fluids from the lung in this stage. However, other tests cannot determine the location of a tumor.
The cancer is in the lining of the bronchus and not in lung tissue. This is also called carcinoma in situ.
In stage 1, the cancer is in the lung. It hasn’t spread to the lymph nodes around it or other parts of the body.
In stage 2, cancer is in the lung tissue and has spread into the lung’s lining or nearby lymph nodes but hasn’t metastasized further.
Stage 3 cancer is in the lung tissue and has spread to nearby lymph nodes or organs, such as the esophagus or heart, but hasn’t spread to distant organs.
In stage 4, the cancer is in the lung tissue and has spread to one or more distant parts of the body. Stage 4A means cancer has spread as one tumor, or it’s spread to the other lung or the fluid around the heart or lungs. In stage 4B, it’s metastasized as two or more tumors.
Treatment for squamous cell lung carcinoma depends on how advanced the cancer is, your ability to tolerate the side effects, and your overall health. Age isn’t usually a consideration.
The treatment you receive will be specific to your situation, but there are some general guidelines for the treatment of each stage.
If you have cancer cells in your sputum, but no cancer is found with diagnostic tests, you’ll usually undergo frequent diagnostic tests (such as a bronchoscopy or CT scan) until a tumor is found.
Surgical removal of the tumor and lung around it without chemotherapy or radiation therapy usually cures squamous cell carcinoma at this stage. This is because cancer hasn’t spread deeper into the tissue of the lungs.
Surgery alone often works at this stage. Some lymph nodes are usually removed to see whether cancer has spread to them.
If cancer cells are found close to the edges of the tissue removed, that could mean that some cancer cells have been left behind. A second surgery may be necessary to ensure all cancer cells have been removed.
If the risk of cancer coming back is high, you might receive chemotherapy after surgery. Occasionally, radiation therapy is used instead of chemotherapy.
This stage is usually treated with surgical removal of the tumor and lymph nodes followed by chemotherapy to kill any remaining cancer cells.
If the tumor is large, you may receive chemotherapy and radiation therapy or radiation alone before surgery to make the tumor smaller and easier to remove with surgery.
Surgery alone can remove some but not all of cancer in this stage, as it’s spread to lymph nodes in your neck or vital structures in your chest. Chemotherapy and radiation therapy are usually given after surgery.
In situations where the treatments above aren’t good options, immunotherapy may be used. This is a type of treatment that helps your immune system fight cancer.
In this stage, cancer has spread throughout your body. Treatment depends on your overall health and how many places the cancer has spread. If you’re healthy enough to undergo surgery, you may have surgery, chemotherapy, and radiation therapy.
Other therapies that may be added to your treatment or used if surgery isn’t an option are:
- Immunotherapy: This enhances your immune system’s ability to fight cancer.
- Targeted therapy: This is therapy targeted to specific characteristics and mutations of your cancer cells.
- Clinical trials: You may be eligible to receive new treatments being studied. Your doctor can help you find clinical trials that might be a good fit. You can also visit ClinicalTrials.gov to learn more.
If treatment isn’t effective or a person decides to stop treatment, palliative care is often given. This is supportive care used to improve the quality of life for people with advanced cancer. It can help relieve cancer symptoms and provide emotional support to those with cancer and their loved ones.
Hospice is palliative care given when the estimated life expectancy is less than 6 months.
Many people don’t experience squamous cell lung carcinoma symptoms until the cancer spreads. Some of the most common symptoms are:
- persistent cough
- bloody sputum
- shortness of breath or wheezing
- chest pain, especially when taking a deep breath or coughing
- unexplained weight loss
- decreased appetite
Some symptoms that squamous cell lung carcinoma may have spread (metastasized) to other areas of the body include:
Metastasis is when cancer spreads to other parts of the body. This may include lymph nodes, the other lung, or other organs.
It’s estimated that metastatic cancer is present at diagnosis in about 40 percent of people with non-small cell lung cancer. Many individuals with non-small cell lung cancer don’t experience symptoms until cancer has started to spread.
For squamous cell lung carcinoma, some of the most common metastatic sites are the:
It’s also possible that squamous cell lung carcinoma can spread to several body areas. For example, cancer could spread from the lung to the bone and the brain.
Treatment for metastasized cancer can depend on several factors, such as your overall health, where the cancer has spread, and how you’ve responded to treatment. Your treatment team will work with you to recommend an approach that best suits your individual treatment needs.
How fast does squamous cell carcinoma of the lung spread?
Non-small cell tumors, like squamous cell lung cancer, tend to grow slower than small cell lung tumors. However, the rate at which this type of cancer grows can depend on several factors, including smoking history and the stage of your cancer.
Doctors may use measures such as growth rate and doubling time to describe the speed at which tumors grow and spread.
Some of the causes and risk factors for squamous cell lung carcinoma include:
Of all the causes of lung cancer, smoking is the most important. According to the National Cancer Institute, smokers are 10 times more likely to get any lung cancer than people who have smoked fewer than 100 cigarettes.
The more you smoke, and the longer you smoke, the higher the risk. If you quit smoking, your risk for lung cancer goes down but stays higher than for nonsmokers for several years after quitting.
The risk of getting lung cancer is almost as high for cigar and pipe smoking as for cigarettes.
Radon is a radioactive, odorless, invisible gas from rocks and soil. It’s a problem only in enclosed places, such as a house, because radon concentration is higher. People who smoke and are exposed to radon have a much higher risk for lung cancer.
Secondhand smoke exposure
Being exposed to secondhand smoke can increase your risk of lung cancer.
Other causes include:
- Exposure to cancer-causing substances. Examples include asbestos, arsenic, chromium, nickel, and some petroleum products. Exposure to these substances most often occurs at work.
- Air pollution. Poor air quality can exacerbate certain conditions, but there are ways to protect yourself.
- Radiation exposure. This may include previous treatment with radiation therapy to your chest or excessive exposure to radiation from getting X-rays.
- Medical history. A personal or family history of lung cancer increases your risk for lung cancer. If you’ve had lung cancer, you have a higher risk of getting it again. If a close relative had lung cancer, you have a higher risk of getting it.
To diagnose squamous cell lung carcinoma, your doctor will first ask you about your symptoms and do an examination.
Next, they’ll do one or more diagnostic tests depending on your history, symptoms, condition, and tumor location. These tests may include:
Usually, a chest X-ray is done first. They’ll then do a CT scan or MRI to better view your lungs and look for a tumor and signs that cancer has spread.
Obtaining some cancer cells
There are a few ways your doctor can obtain these cells. They may take a sputum sample. If there is any fluid around your lungs, it will usually have some cancer cells. Your doctor may obtain a sample with a needle inserted through your skin (thoracentesis). Then, your cells are examined under a microscope for signs of cancer.
A biopsy is another way to look at cells under a microscope. Your doctor can take a biopsy of the tumor using a needle inserted through your skin (needle biopsy) or a tube with a light and camera that’s inserted through your mouth or nose (bronchoscopy).
If cancer has spread to the lymph nodes or other structures between your lungs, your doctor can do a biopsy through an incision in your skin (mediastinoscopy).
This imaging test shows a bright spot in any tissue where there’s cancer. PET scans look for metastases near the tumor or in the body.
This is an imaging test that shows a bright spot in areas of bone where cancer has spread.
Pulmonary function tests
These test how well your lungs work. They’re used to show if you’ll have enough lung function left after surgical removal of the lung tissue with the tumor.
These tests can see if cancer cells have certain gene mutations or express specific types of proteins on their surface. Molecular tests can help determine if targeted therapy or immunotherapy may be effective.
The outlook for non-small cell lung cancers, such as squamous cell carcinoma, is better than small cell lung carcinomas. It’s also better when it’s caught and treated early. It can even be cured if caught early enough.
The outlook for people with cancer is measured by 5-year relative survival rates. This indicates the percentage of people who have a specific type of cancer who are alive 5 years or more after getting a diagnosis relative to those who are not.
- Localized: This is non-small cell lung cancer that hasn’t spread outside the lung. The 5-year relative survival rate is 65 percent.
- Regional: This is non-small cell lung cancer that has spread to the lymph nodes and other nearby organs in the chest. The 5-year relative survival rate is 37 percent.
- Distant: This is when non-small cell lung cancer has spread to more distant organs of the body, such as the liver, brain, or bones. The 5-year relative survival rate is 8 percent.
These percentages are only a guide based on averages. Everyone is different. The percentages show that the key to having the best outlook is early detection and treatment before cancer spreads.
The outlook for a person is influenced by many factors, such as age, general health, response to treatment, and treatment side effects. A doctor will evaluate all of this information to give you an outlook that’s specific to you.
Squamous cell lung carcinoma is a type of non-small cell lung cancer. It impacts the cells that line the surface of your airways.
Squamous cell lung carcinoma can occur in six stages. Staging is done based on tumor size and whether cancer has spread to the lymph nodes or other parts of the body. Many people don’t have symptoms until the cancer has begun to spread.
There are many treatment options for squamous cell lung carcinoma. The recommended treatment can depend on various factors, such as the stage of cancer, overall health, and the presence of specific mutations in the cancer cells.
You can significantly decrease your risk for lung cancer by not smoking and avoiding radon or secondhand smoke exposure. The overall outlook improves with early diagnosis and treatment, so be sure to talk with a medical professional if you’re concerned about developing lung cancer.