Squamous cell lung cancer is a subtype of non-small cell lung cancer. It is actually one of the most common types of carcinoma in the lungs. “Squamous cell” refers to flat cells that make up the air passages throughout the lungs. They used to be epidermoid cells, similar to those found in the skin, but became cancer and now turned into a tumor.
This article will go through squamous cell carcinoma’s essentials and briefly talk about its diagnosis and prognosis.
What Is Squamous Cell Lung Cancer?
Squamous cell lung cancer is also known as epidermoid carcinoma. It is a frequently-occurring type of NSCLC. 30% of cancer cases occurring in the lung will be squamous cell lung cancer. It develops in the bronchioles and grows more slowly than other lung cancer types, but these patients need to be assessed from an early phase of the disease to figure out the disease stage and what we can do about it.
Squamous cell lung cancer occurs when the abnormal cells of the lung or airways multiply out of control and form a tumor. The tumor can spread to other parts of the body like the brain, liver, and lymph nodes. It is the second more common lung cancer after adenocarcinoma, and it is strongly associated with smoking.
What Causes Squamous Cell Lung Cancer?
The causes of squamous cell lung cancer are similar to the rest of small-cell lung cancers. The most common cause of is chronic tobacco smoking. It has a solid relationship with smoking all types as cigar, pipe, marijuana, and cigarette smoking.
Secondly, we should list uranium and radon exposition. Actually, uranium miners have a higher incidence of lung cancer regardless of the type. Radon is an inert gas that results from the decay of uranium. Regular breathing in an environment contaminated with radon gas increases the chance of developing squamous cell lung cancer.
Thirdly, we have asbestos exposure as another cause of squamous cell lung cancer. Asbestos is found in our ceiling tiles, fireproofing, and insulation material. People living in this type of building have an increased risk of squamous cell lung cancer.
Other risk factors for squamous cell lung cancer include passive smoking, age, exposure to gasoline, arsenic, talcum powder, family history, and recurring lung inflammation from pneumonia or tuberculosis.
Remember that cancer is a multifactorial disease, and we won’t be able to trace back the exact cause of squamous cell lung cancer in many cases. Instead, we have different risk factors and expositions that may contribute to the formation of a malignant tumor.
Major Signs and Silent Symptoms
Squamous cell lung cancer has several symptoms, and most of them are similar to those found in the rest of non-small cell lung cancer.
One of the most important symptoms is shortness of breath, also known as dyspnea. In this case, there’s a blockage of the airways, and this is mainly the case because squamous cell lung cancer develops in the airways. The second most common symptom is coughing up blood, medically known as hemoptysis. This is also very common in squamous cell lung cancer because the tumor in the airways has abnormal and very fragile blood vessels. Thirdly, pain is also an important symptom, usually located in the center of the chest. Other symptoms can be felt when cancer grows bigger or spreads to other parts.
It is essential to highlight that squamous cell lung cancer tends to give out symptoms earlier than other cancer types. It starts to grow in the lungs’ airways as opposed to different types that start to grow in the edges (for example, adenocarcinoma). Thus, it causes obstruction, bleeding, and other symptoms much faster.
Diagnosis of Squamous Cell Lung Cancer
The diagnosis of squamous cell lung cancer is similar to the rest of non-small cell lung cancers. The only difference in diagnosis is that this cancer is more likely to be detected in an early stage. In most cases (up to 75% of patients), cancer will be detected before the tumor has spread to other areas.
These exams can be useful for the diagnosis of squamous cell lung cancer:
- Imaging tests: It is usually enough with X-Rays, and sometimes a CT scan. X-rays show an image traditionally located in the center of the chest in the form of a nodule. Then, a CT scan is performed to evaluate the exact placement of cancer, its relation to nearby structures, the extent of cancer, and any local or nearby spread.
- Sputum cytology: Performing sputum cytology in patients with productive cough can be useful to detect cancer cells and diagnose the type of lung cancer. It may also be helpful to diagnose an infection.
- Tissue sampling: It is a direct biopsy of the tumor using an instrument that goes through the throat and reaches the airways. There are different ways to obtain a biopsy, including biopsies performed as a part of the surgery to treat squamous cell lung cancer.
Prognosis Of Squamous Cell Lung Cancer
Squamous cell lung cancer sometimes causes Pancoast syndrome. This syndrome is triggered by lung cancers that develop in the upper part of the lungs. As cancer grows, it pushes away other structures, causing pressure upon the nerves, leading to abnormal sensitivity in the upper limbs and shoulders. These patients develop shoulder pain and may report a tingling sensation in the inside of the arms, weakness of the hands, and much more.
The survival rate of squamous cell lung cancer depends on the stage and extent of the tumor. According to statistics, 50% of non-small cell lung cancer patients are still alive after five years if they are detected early. However, new studies and treatments give squamous cell lung cancer a better prognosis than stated in the available literature in 2013.
Prognosis depends on the stage of cancer, the treatment you have, and your comorbidities. So, talk to your doctor to obtain a more accurate understanding of what to expect in your case.
References:
Perez-Moreno, P., Brambilla, E., Thomas, R., & Soria, J. C. (2012). Squamous cell carcinoma of the lung: molecular subtypes and therapeutic opportunities. Clinical cancer research, 18(9), 2443-2451.
Derman, B. A., Mileham, K. F., Bonomi, P. D., Batus, M., & Fidler, M. J. (2015). Treatment of advanced squamous cell carcinoma of the lung: a review. Translational lung cancer research, 4(5), 524.
Lemjabbar-Alaoui, H., Hassan, O. U., Yang, Y. W., & Buchanan, P. (2015). Lung cancer: Biology and treatment options. Biochimica et Biophysica Acta (BBA)-Reviews on Cancer, 1856(2), 189-210.
Sabbula, B. R., & Anjum, F. (2020). Squamous Cell Lung Cancer. StatPearls [Internet].
