Your In-Depth Guide to Squamous Cell Carcinoma of the Lungs

Symptoms, Diagnosis, Treatments, and Prognosis of Squamous Cell Lung Cancer

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Man smoking a cigarette in a park and coughing, on a spring day
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Squamous cell carcinoma of the lungs is one form of non-small cell lung cancer. Non-small cell lung cancers account for about 80 percent of lung cancers, and of these, roughly 30 percent are squamous cell carcinomas.

Overview

Squamous cell carcinoma begins in the tissues that line 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. These cancers can, however, occur even in people who have never smoked.

Subtypes

Squamous cell lung cancers are further divided into 4 subtypes by what they look like under a microscope and how they behave.

These include:

  • Primitive
  • Classical
  • Secretory
  • Basal

We know there are survival differences between these subtypes but are just learning about how each type may respond differently to different drugs. Most subtypes respond to at least one of the commonly used chemotherapy drugs. An exception may be secretory squamous cell lung cancer.

This subtype is less sensitive to commonly used chemotherapy drugs because it tends to be slower growing (and chemotherapy is often most effective on fast-growing cancers since it targets dividing cells).

Symptoms

Common signs and symptoms of lung cancer include a persistent cough, coughing up blood, shortness of breath, 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), and a respiratory infection such as pneumonia may be the first sign that something is amiss.

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, such as nerves. 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.

Diagnosis

Squamous 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
  • Bronchoscopy
  • PET Scan. A PET scan is a "functional" test designed to look for actively growing tumors and is often done to look for any evidence of spread (metastasis)

Depending on the results, your doctor will usually want to obtain a sample of tissue (lung biopsy) to confirm the diagnosis and will order further tests to check to see if your cancer has spread.

Staging

Squamous 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, the most common sites being the bones, brain, liver, or adrenal glands

Doctors also use another, more confusing way to decide upon the stage of a lung cancer called  TNM staging. 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 (metastasized) to regions of the body outside of the lungs, or to the other lung (represented by an M). For example, your doctor may describe your lung cancer as T3N2M0. 

Causes

Squamous cell carcinoma of the lung is a type of lung cancer strongly associated with smoking, but other causes can contribute as well. Radon exposure in the home is the second leading cause of lung cancer. Occupational exposures, such as to diesel fuel and more are also important risk factors in the development of squamous cell lung cancer.

Genetics may play a role as well, and the risk of lung cancer is increased for people who have other family members with the disease.

Treatments

Depending upon the stage of squamous cell carcinoma of the lungs, treatment may include surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, 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.

Surgery

Lung cancer surgery may be possible for squamous cell carcinoma. With stage 1A squamous cell lung cancer, surgery alone may be curative. Surgery may also be considered for those with stage 1B, stage II, and stage 3A lung cancer, usually combined with chemotherapy and radiation therapy. Sometimes, a tumor may initially be inoperable but may be reduced in size with chemotherapy and/or radiation therapy so that surgery is then possible. When chemotherapy is done to reduce the size of a tumor prior to surgery it is referred to as "neoadjuvant chemotherapy." Recently, success has been demonstrated in using immunotherapy to reduce an inoperable tumor in size so that surgery may be performed.

Chemotherapy

Chemotherapy may be used alone, in conjunction with radiation therapy, or before or after surgery for lung cancer. Squamous cell carcinoma of the lungs responds somewhat differently than other lung cancers such as adenocarcinoma to chemotherapy medications. Common medications used initially for this type of cancer include Platinol (cisplatin) and Gemzar (gemcitabine). For those who respond to treatment, continuous (maintenance treatment) with Tarceva (erlotinib) or Alimta (pemetrexed) may be used.

Radiation Therapy

Radiation Therapy may be used to treat cancer or to control symptoms related to the spread of cancer. Radiation may be given externally, or internally (brachytherapy) in which radioactive material is delivered to a precise area of the lungs during a bronchoscopy.

Targeted Therapy

You may have heard about the use of targeted drugs to treat EGFR mutations in lung adenocarcinoma. EGFR, or epidermal growth factor receptor, is a protein involved in driving the growth of a cancer. Squamous cell carcinoma of the lungs may also be treated by targeting the EGFR pathway, but by a different mechanism.

Instead of targeting EGFR mutations, anti-EGFR antibodies are a class of drugs used to bind to EGFR on the outside of cancer cells. When EGFR is thus bound, the signaling pathway which tells the cell to grow is halted. Portrazza (necitumumab) was approved in 2015 to use along with chemotherapy for advanced squamous cell cancers. Clinical trials are evaluating other drugs, such as afatinib and more for the treatment of squamous cell lung cancer.

Immunotherapy

Immunotherapy drugs were first approved for the treatment of lung cancer in 2015, and now combinations of these drugs are being studied in clinical trials.

In 2015, the first immunotherapy treatment was approved for people with this disease. The medication Opdivo (nivolumab) is a form of immunotherapy that, very simplistically, enhances our body's own immune system's ability to fight off cancer cells. 

To understand how these drugs work, it may help to think of your immune system as a car.  The "brakes" are controlled by a protein called PD-1. Opdivo in this analogy works to block PD-1—the brakes—allowing the immune system to fight against the cancer without interference—in essence, taking the brakes off the car. The treatment is currently approved for people with metastatic squamous non-small cell lung cancer whose cancer has progressed during or after standard platinum-based chemotherapy.  (Platinum-based chemotherapy refers to a chemotherapy regimen including Platinol (cisplatin) or Paraplatin (carboplatin)).

Since that time, two other immunotherapy drugs have been approved, Keytruda (pembrolizumab), and Tecentriq (atezolizumab).

Prognosis

Before answering the question “what is the prognosis of squamous cell lung cancer?” it is important to talk about what the numbers describing survival rate really mean. First of all, everyone is different. Statistics tell us what the “average” course or survival is, but they don’t tell us anything about specific individuals. Many factors can affect the prognosis of squamous cell lung cancer including your age at diagnosis, your sex, the condition of your general health, and how you respond to treatments.

It is also helpful to keep in mind that statistics are based on information that is several years old. As new treatments become available, these numbers may not accurately reflect what your prognosis is today. For example, the five-year survival rate for a lung cancer reported in 2018 is based on people who were diagnosed in 2013 and earlier. Since many significant treatments for squamous cell carcinoma of the lung were only approved after 2013, statistics are not necessarily indicative of how someone will do today.

At the same time, there have been more new treatments approved for the treatment of lung cancer in the last 5 years, than in the 40 year period prior. For example, the drug Portrazza was not available when the people in these studies were diagnosed. What this means is that the current reported survival rates fail to take into account how someone will be expected to do on any of these new treatments.

There is a lot of hope for those diagnosed with lung cancer today, but unfortunately, the statistics you will read may not be helpful in understanding this hope.

Non-small cell lung cancer survival rates vary with stage, with the average five-year survival being 50 percent (or better) with stage 1 disease, but only two to four percent with stage 4 disease. The overall five-year survival rate for lung cancer is sadly only about 18 percent. Again it's important to note that the numbers in these rates do not reflect improvements with the newer drugs and procedures now available.

Estimating Your Prognosis

When looking at prognosis it's important to note that all squamous cell lung cancers are not the same. In fact, if there were 300 people with squamous cell lung carcinoma in a room, they would have 300 unique cancers. Your particular cancer may have molecular characteristics which either increase or decrease your prognosis. (Your oncologist may discuss some of these with you). In addition, research is looking for other ways of estimating the prognosis of an individual squamous cell carcinoma based on findings such as circulating tumor cells found on a liquid biopsy and more.

Coping

A diagnosis of squamous cell carcinoma of the lungs is frightening and you may feel very alone. The phrase "it takes a village" was never more appropriate than when talking about lung cancer. Reach out and allow (that part is sometimes the key) your loved ones to support you. 

Take the time to learn about your cancer. Studies tell us that people who better understand their cancer not only feel more empowered, but that knowledge can sometimes make a difference in survival as well. See if you can find a support group for people with lung cancer in your community, or take the time to connect with the wonderful lung cancer community online.

These people will not only welcome you in and support you but can be a great source of the latest information and research as well. Check out the lung cancer organizations such as LUNGevity, the American Lung Association Lung Force, and the Lung Cancer Alliance. When searching for others with lung cancer on social media, the hashtag is #LCSM which stands for lung cancer social media. If you are under the age of 50, make sure to check out the Bonnie J. Addario Lung Cancer Foundation, an organization that takes a special interest in lung cancer in young adults.

Most of all, be your own advocate for your cancer care. The treatment of lung cancer is changing rapidly, and people are increasingly being called upon to be an active part of their treatment team. In fact, there are many survivors currently alive that are only alive because they educated themselves and were an advocate for their care. Since it is difficult for a general oncologist to stay abreast of the rapid changes in treatment, many lung cancer survivors recommend obtaining a second opinion at one of the larger National Cancer Institute-designated cancer centers which have lung cancer specialists available.

If Your Loved One Has Squamous Cell Lung Cancer

Coping with lung cancer in a loved one can be a challenge. Not only are you facing what your loved one is from your angle, but the sense of helplessness can be heart-wrenching. You can be reassured that most people have no idea how to react when a loved one has lung cancer. Asking about specific ways in which you can help, rather than saying "call me if you need me," is a way in which you can express your caring and lessen their burden. Take a moment to learn about what it's really like to live with lung cancer and how you can support a loved one with cancer.

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