Lung cancer: Squamous cell carcinoma

Lung cancer is considered one of the dangerous cancers among all and it is estimated to cause more than 150000 deaths each year in the United States alone. At the same time, there are more than 220,000 lung cancer patients diagnosed each year in the US and many of them are not lucky enough to survive for more than 5 years from the day of their diagnosis.

Why lung cancers have a poor prognosis?

According to researchers, most lung cancers are slow growing and will take many years before they manifest. Due to this reason, lung cancers can go unnoticed until late and by the time it is detected, it may have already spread to nearby as well as distant organs. Once metastasized, lung cancers are hard to treat as they have the potential to spread to organs such as the brain, liver, bone, adrenals, small intestine…etc.

What are the different types of lung cancers?

Most lung cancers belong to the group, ‘non-small cell lung caners’ while rest belongs to ‘small cell lung cancers’. Non-small cell lung cancers are made up of three distinct histological (cellular) types and these include, squamous cell carcinoma, adenocarcinoma and large cell carcinoma of the lungs. Out of which, adenocarcinomas are considered to be the commonest lung cancer which accounts for almost 40 – 50 % while squamous cell carcinoma accounts for almost 25 – 40 % of all lung cancers. However, squamous cell carcinomas used to be the commonest lung cancer few decades back.

What is the histological significance of squamous cell carcinoma of the lung?

Squamous cell carcinoma is thought to arise from the ‘reserve cells’ present in the lining epithelium of airways in the lungs (Bronchi). These cells facilitate repair of damaged cells of the bronchi in the normal state and at some point, becomes mutated and therefore cancerous. Therefore, these cancers are usually located in the center of the lungs and could grow into large sizes and form cavities in certain instances. With advancing disease, these cancers could become locally invasive or spread through blood and lymph towards distant organs.

What are the causes for squamous cell carcinomas of the lungs?

In almost all instances, the squamous cell carcinomas of the lungs are related to smoking and the risk of developing the cancer has a direct association with both the number and the duration of smoking. Thus, it may manifest even in younger patients and when someone withholds smoking, the risks become significantly low. However, there are several other risk factors contributing to this type of cancers and among them, family history, second hand smoking, exposure to certain metals and dusts…etc could be highlighted.

How does these cancers manifest?

With time, these patients could develop a cough, which may not respond adequately for usual treatment methods. It can persist and sometimes become worse, gradually. At the same time, breathlessness and blood stained sputum could also be noted although this may not be the case in many patients. Non-specific symptoms such as weight loss, loss of appetite and low-grade fever can also be present in some patients.

How squamous cell carcinomas of the lungs are diagnosed?

A definite diagnosis of squamous cell carcinoma requires analyzing a tissue or fluid specimen obtained from the lungs (at the site of the cancerous lesion or from any fluid collections) and this may be done through CT guided aspiration, through bronchoscopy or else using other surgical methods. However, in certain instances, cancer cells may be visible in the sputum samples as well.

What are the treatment modalities available for lung cancers?

Surgical excision of the cancerous tissue or sometimes an entire half of the lung would be necessary to treat these patients although the 5 year survival rate could be very poor among most of them. However, if the cancer is detected early and if it is well localized, the chances of survival could be as high as 40% and it may reach 80% when the patients are less than 30 years old.