Small Cell vs Non-Small Cell Cancer
Two types of lung cancer exist, which can be described as small cell and non-small Cell. Small cell lung cancer is becoming much less prevalent in this country, with data showing that only 14% of all lung cancers are classed as small cell</>.
Small Cell Lung Cancer (SCLC)
SCLC is staged using the TNM staging system. Those who have stage 1 to 3 of the illness, so long as there is no malignant pleural effusion, are classed as having a ‘limited’ disease. Around a third of all SCLC patients fall in this category. The others fall into what is known as ‘extensive’ disease, which means they also have malignant pleural effusions in other sites.
It is very important that SCLC is staged properly, so that the right type of treatment can also be offered. This is also because the stage is one of the main determining factors of the prognosis. Usually, oncologists will use either the Eastern Cooperative Oncology Group system of status performance, and/or the Karnofsky performance index.
The reason why SCLC is called ‘small cell’ is because the cancer cells are predominantly filled with nucleus, and are quite small in size. In most cases, smoking is a main contributing factor in SCLC. In fact, it is very rare for a non-smoker to develop it. It spreads quickly and the recommended treatment is chemotherapy, rather than surgery.
Small Cell Mesothelioma
There is also what is known as small cell mesothelioma, which is an incredibly rare form of cancer. In fact, only about 6% of all mesothelioma cases are classed as being small cell. In most cases, small cell mesothelioma develops together with other forms of mesothelioma.
It should be noted that while it is called small cell mesothelioma, only about 40 percent of the cells found in the tumor are small cell mesothelioma cells. Approximately the same amount are the usual epithelial mesothelioma cells and the remaining 20 percent are indistinguishable cancer cells.
While small cell mesothelioma and small cell lung cancer are different, their symptoms tend to be similar. The common symptoms for mesothelioma small cell include shortness of breath, dry cough or wheezing, pain in the abdomen or chest, and respiratory complications. On the other hand, some of the symptoms of small cell lung cancer include pain in the chest, difficulty in breathing, hoarseness, wheezing, blood in sputum, unexplained weight loss, feeling tired, and loss of appetite.
Non-Small Cell Lung Cancer (NSCLC)
Three types of NSCLC exist, but they behave very similarly, which is why they are grouped together. Additionally, they respond to treatment in a different way than SCLC. NSCLC is responsible for about 87% of all lung cancers. The three types are:
- Adenocarcinoma, which is the most common type. The airway is lined with mucus making cells, in which this cancer develops. Different subtypes of this form of NSCLC exist, with bronchiolo alvealoar carcinoma being the most common.
- Squamous cell cancer, which starts in the flat cells that cover the surface of the airways. This form is often caused by lung cancer. The number of incidents for this type is dropping.
- Large cell carcinoma, which, as the name suggests, looks very large. It is also a fast growing type of cancer.
Sometimes, the type of NSCLC present is not clear, not in the least because, in the best possible situation, the cells haven’t developed much yet. These underdeveloped cells are known as ‘undifferentiated cells’. This does not, however, have an influence on treatment.
Risk Factors of NSCLC
There are risk factors that someone can change, by altering their lifestyle, and risk factors that cannot be changed. NSCLC is affected by both of these types of risk factors. The ones that can be changed focus mainly on smoking. These include cigars, cigarettes, and pipes. Additionally, secondhand smoke is classed as a risk factor for NSCLC.
Another factor that you can change is radon exposure, although it is debatable to what extent this can be avoided. Today, we know that radon is a carcinogenic and must be avoided. However, it continues to be the second leading cause of lung cancer according to the Environmental Protection Agency. Radon is found in significantly higher levels in basements, so if you spend a lot of time there, you should have the air quality checked.
Asbestos exposure is also a leading cause of NSCLC. As with radon, it can be debated to what extent this can be avoided. Unfortunately, information continues to be lacking about how much exposure people have to have in order for them to become affected. What is known, however, is that those who smoke are at a much increased risk. Thanks to government legislation, the incidences of people developing NSCLC due to asbestos have gone down tremendously.
Lastly, there are a number of other workplace-related substances that can increase the risk of developing NSCLC. These include:
- Exposure to uranium or other radioactive substances
- Inhaling various chemicals like chloromethyl ether, mustard gas, coal products, chromium compounds, nickel compounds, vinyl chloride, silica, cadmium, beryllium, and arsenic
- Exposure to diesel exhaust fumes
There is also a suggestion that arsenic in drinking water, which is common in South America, increases the risk of developing NSCLC. Additionally, tests have shown that smokers who would take beta carotene supplements, particularly the AREDS1 supplement designed for age-related macular degeneration, can increase the chance of developing NSCLC.
The above are classes as risk factors that can be changed, although it can be debated as to how much it is possible for someone to avoid arsenic in drinking water, for instance. Meanwhile, there are some risk factors that people cannot change. The first is radiation therapy that affected the lungs. If someone has already had a form of cancer and they had to receive radiation therapy for it, particularly on the chest area, then they are more likely to develop NSCLC. Examples include people with breast cancer or Hodgkin disease. Interestingly, in the case of breast cancer, the chance is only increased if radiation was applied after a mastectomy, not after a lumpectomy.
The next unavoidable risk is air pollution. Air pollution levels can be incredibly high in certain areas, particularly metropolitan areas. While this risk is negligible when compared to smoking, it is believed that around 5% of deaths of lung cancer around the world are caused by air pollution, and these numbers are rising.
There is also the familial history factor. If any direct relative has developed lung cancer, you are much more likely to develop it yourself. This risk is even larger if you also smoke, or are exposed to any other avoidable risks.
Lastly, there is some question on whether or not smoking marijuana, talcum powder, and talc, can increase the risk of developing lung cancer. Various lawsuits are currently taking place with regards to talcum powder, although it is not clear whether this is in relation to lung cancer, or to other forms of cancer.
Developing SCLC is incredibly rare nowadays, although not unheard of. It is also possible for someone to develop small cell mesothelioma, although that is even rarer. NSCLC is far more common, however. Interestingly, the risk factors seem to be fluctuating. For instance, although it is known that asbestos should be avoided due to its carcinogenic properties, the number of people who develop NSCLC as a result of asbestos exposure is dropping. At the same time, the number of people who develop it due to air pollution is rising. As such, medical professionals are continuously researching the various forms of cancer, in the hopes of removing risk factors. The biggest one, naturally, is smoking and people should commit to stopping that habit straightaway.