Cancer affects one in three people in the United States. In men and women, lung cancer is the third most common cancer. Some cancers are more common in men, and some are more common in women. Breast cancer is more common in women, for example.
Lung cancer is one of the leading causes of cancer death around the world. (1)
Table of Contents
- What is Lung Cancer?
- Types of Lung Cancer
- Types of Lung Tumors
- Causes and Risk Factors of Lung Cancer
- Symptoms of Lung Cancer
- Treatment for Lung Cancer
What is Lung Cancer?
Lung cancer is a type of cancer that forms in the lung, usually in the tissue cells that line the air passages. The body contains trillions of cells that grow and divide throughout our lifetime as necessary. Any cancer occurs when cells continue to make new cells, but old or abnormal cells do not die out for different reasons.
This year, new lung cancer rates occurred in around 200,000 people, almost equally split between women and men. The number of deaths from lung cancer was near 100,000 in comparison. Lung cancer makes up around 25 percent of all cancer deaths, making it one of the leading causes of cancer death. (2)
A diagnosis of lung cancer often starts in old age, over 65 years old. It is exceedingly rare to get lung cancer before the age of 45 as well. The average number for a lung cancer diagnosis is 70 years old. However, there is an upside to this. The number of lung cancer cases has been on a steady decline over the last several years. This is because more people are quitting smoking. (3) (4)
Types of Lung Cancer
The lungs consist of two sponge-like organs, made up of three sections or lobes. Within the lungs are the trachea or windpipe, which divides into more tubes called bronchi.
Lung cancer often begins in the cells of the bronchi and other parts of the lungs like the bronchioles. The bronchioles transport gas and protect the lungs from damage.
There are two different types of lung cancer. But, there are a few types of tumors that can develop within lung cancer as well. And, within each one are many subtypes. Read on to learn more about each type of lung cancer, its treatment, and more.
Non-Small Cell Lung Cancer (NSCLC)
For the most part, lung cancers fall into this category. Around 80 percent of lung cancers are non-small cell lung cancer. Within NSCLC, there are a few main subtypes. These include squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. The reason for the grouping is because they often require a similar type of treatment option.
Adenocarcinomas are more likely to be discovered before it becomes too large of a problem to solve. Women are more likely to develop this type of lung cancer than men. And, it is much more common in young people than older adults. While this type of cancer shows up for those who currently smoke or used to smoke, this type is also frequently seen in non-smokers. Furthermore, 10-15 percent of this type of cancer arises in those who have never smoked. Lung cancer in those who have never smoked amounts to 16,000 – 24,000 deaths annually in the US, which ranks as one of the top ten causes of cancer death as a separate body from smoking-related cancer. (5) (6)
Squamous Cell Carcinoma: (Subtype)
There are flat cells that line the inside of the airways in the lungs. Those are called squamous cells. That is where lung cancer develops in this subtype. These are most frequently in those who have a history of smoking. Filter cigarette smoking is also a case of examination when discussing this type of lung cancer because filters have changed drastically over the years, emitting more toxins. (7)
This type of lung cancer is typically in the central part of the lungs or the bronchus.
Large Cell (Undifferentiated) Carcinoma (Subtype)
This type of lung cancer is different from the others in that it is often harder to catch, spreads faster, and eventually becomes harder to treat. In one case, an aggressive large cell was undiagnosed in a middle-aged man until his autopsy. One point to note is oxidative stress can put more damage on large cell carcinomas. (8)
There are only a few other subtypes of non-small cell lung cancer (NSCLC). These include adenosquamous carcinoma and sarcomatoid carcinoma. They are much less common than the others mentioned above.
Small Cell Lung Cancer (SCLC)
This type of cancer is sometimes called oat cell cancer, and it spreads faster than any other type of lung cancer. It can often be an overlooked diagnosis because it is difficult to spot small cell lung cancer during a lung screening. (9) This type of cancer accounts for 10 to 15 percent of all lung cancers.
Types of Lung Tumors
While there are a few main subtypes of small cell lung cancer and non-small cell lung cancer, there are also a few different types of lung tumors to recognize.
Cancers that Spread to the Lungs
In many cases, cancer can spread to the lungs, even though it originates somewhere else. For example, breast, kidney, or skin cancer can eventually spread to the lungs. But, even though they move to the lungs, that does not turn it into lung cancer. It is still the original type of cancer diagnosed. It has simply metastasized or spread to the lungs as well.
Rare Lung Tumors
Some examples of rare lung tumors often treated differently include sarcomas, adenoid cystic carcinomas, lymphomas, and even benign tumors called hamartomas.
Lung Carcinoid Tumors
These are also rare types of lung tumors, which grow slowly in comparison to other types. Less than 5 percent of lung tumors are considered lung carcinoid tumors.
Causes and Risk Factors of Lung Cancer
The most frequent cause or risk factor of lung cancer is smoking, but many other factors can exacerbate or cause this common cancer. That is especially true for the 10 to 15 percent of people who acquire lung cancer and have never smoked a day in their lives.
That most often includes tobacco smoke, cigars, and pipes. Smokers make up 80 percent of lung cancer-related deaths. For women, the number ranges from 70 to 80 percent risk, and for men, it is 90 percent of the risk factor for lung cancer. Smokers expose themselves to harmful tar and chemicals, increasing inflammation in the lungs and increasing chances of lung cancer. (10) Those exposed to asbestos or radon on top of smoking at also at an increased risk. Choosing low-tar of light cigarettes does not lower the chances of developing lung cancer. Smokers of traditional cigarettes are at just as much of a risk. For a craving for nicotine, e-cigarettes may be a better alternative, although more research is necessary to determine the risk factors. (11) More research points to e-cigarettes possibly causing cancer to the lungs in mice. (12)
Secondhand or Passive Smoking
Secondhand tobacco smoking accounts for around 1.6 percent of lung cancers. There is more of a risk if you live with someone who smokes as well. More research is necessary to provide substantial evidence that air and other pollutants such as pesticides and dioxins as causing lung cancer. (13) Secondhand smoke may account for around 7,000 deaths each year.
Even alcohol consumption may be a cause of lung cancer among never-smokers. In one study, alcohol consumption over 30 g exhibited a slightly higher risk than those who drank no alcohol. (14) Any harmful lifestyle practice can increase the risk of inflammation in the body. Even if it does not seem related, there are often risk factors that can attribute to different types of cancer risk.
Exposure to Radon and Asbestos
Some people are more exposed to radon and asbestos than others, but some are unaware of this type of harmful exposure. For example, those who work in mines, textile plants, or shipyards are often more exposed to asbestos than others. That makes them much more likely to die from lung cancer than those who work in unharmful exposure environments. People around more asbestos are also more prone to develop a different type of cancer that starts in the outer lining of the lungs called mesothelioma. Asbestos is still present in many homes, especially older homes. New commercial and industrial products are now under more pressure to eliminate asbestos from their ingredients.
Radon is a naturally occurring gas that comes from the breakdown of uranium in rocks and soil. Radon is the second leading cause of lung cancer in non-smokers, according to the Environmental Protection Agency (EPA). It is exceedingly rare to become exposed to radon outdoors, but indoor exposure can be dangerous because it becomes concentrated. When you breathe in radon, there is a small amount of radiation exposure. Homes in the U.S. may have high levels of radon, and it is most common in basements. Radon testing is typically recommended or required when buying a new home.
Many studies point to some forms of air pollution as a potential cause of lung cancer, especially among non-smokers. In Europe, the average rate of lung cancers due to air pollution amounts to 11 percent of cases. (15) Exposure to harmful air pollutants puts too much oxidative stress on the body, which may cause a build-up of inflammation. That may then lead to dysfunction of the autonomic nervous system. Eventually, air pollutants may cause changes to lung function, blood pressure, heart rate, and even respiratory changes. In the long term, pollutants may cause even more than lung cancer, such as bronchitis, asthma, and even atherosclerosis.
There may be a hereditary link between lung cancer and genetics, and there are many subsets, too. There may also be some connection between the risk factors for lung cancer and a change in genetics. That can lead to abnormal cell growth and sometimes cancer.
Another way to get lung cancer is through inherited genes from your parents. DNA mutations can put people at a greater risk of developing some types of lung cancers. However, there is very little research to suggest that only genetics can cause lung cancer by itself. If a person inherits a specific gene mutation, such as chromosome 6, there is a greater chance of cancer, even if the person only smokes a little or non at all. That is because some people cannot break down cancer-causing chemicals as well, such as those in cigarette smoke.
Adenocarcinoma is more common among young Asian women who inherit a specific gene change. That gene change shows up as producing too much of an EGFR protein, which comes from an abnormal EGFR gene. There are many variations in gene changes and mutations that can determine an individual’s risk of developing lung cancer, especially when they have poor lifestyle habits on top of gene mutations.
Currently, there are no regular tests to determine gene variations that can put certain people at a higher risk. The only recommendation is to stay away from tobacco smoke and other harmful pollutants/toxins altogether or as much as possible.
Certain Foods and Supplements
While many foods decrease the risk of inflammation and disease, such as fruits, vegetables, and carotenoids, some research suggests high doses of select foods and supplements may have the opposite effect. That is only true for extremely high amounts of beta-carotene in supplement form when it comes to healthy options. Some research shows an increased risk of cancer when eating cured meats such as duck, sausage, and pork. Furthermore, deep-fried cooking and chili may be associated with an increased risk of lung cancer. (16) Eating a healthy diet full of healthy fats, lean protein, fruits, and vegetables may increase your chances of avoiding lung cancer as well. The more healthy antioxidants and anti-inflammatory foods in your diet, the less oxidative stress, and damage are on the body.
Talc and Talcum Powder
More research is necessary to determine these as direct links to lung cancer. However, there is some evidence that suggests it may be a hidden cause. Talc is most commonly in powder for babies, cosmetic use, or industrial settings. In its natural form, talc may contain asbestos. Some studies show high exposure to talc may increase the risks of lung cancer. (17) While more research is necessary, monitoring talc and talc powder exposure on an individual case basis may be helpful. That may be especially true when there is a chance of extreme exposure levels.
Any smoke may cause damage to the lungs, so marijuana smoke is another potential cause of lung cancer. However, more research is necessary to determine the statistics because it is still illegal in many areas. It does contain some tar that is also in cigarette tobacco smoke. Marijuana is inhaled deeply and held for long periods than tobacco smoke as well, so that is a potential risk factor, too. Many people who smoke marijuana smoke traditional tobacco cigarettes, making it more difficult to gather statistics, too.
Lack of Physical Activity
Exhibiting healthy lifestyle habits plays a role in maintaining lung and overall health. Those who exercised regularly had a much lower risk of lung cancer, even at a moderate level. Exercising moderately to a high amount shows a 13 to 30 percent reduction in lung cancer. And, among heavy smokers, regular exercise may decrease lung cancer risk overall. (18)
Symptoms of Lung Cancer
With early stages of lung cancer, there are typically no initial signs or symptoms. However, there are many symptoms to look out for as the disease progresses.
The main symptoms of lung cancer include:
- A persistent cough lasting more than two to three weeks
- Coughing up blood
- Frequent chest infections
- A worsening cough
- Experiencing breathlessness often
- Achiness or pain when breathing
- Unexplained weight loss or loss of appetite
Some other symptoms that are not as frequent but should check out include:
- Swelling in the face or neck
- Chest or shoulder pain that persists
- Difficulty swallowing
- Changes in finger appearance, such as ends becoming larger (finger clubbing)
Treatment for Lung Cancer
Treatments for lung cancer range depending on the type of cancer you have and how much it spreads. From surgery, chemotherapy, radiation, and targeted therapy, there are four main treatment options. For the most part, non-small lung cancer may be treated with surgery, chemotherapy, radiation therapy, and targeted therapy, or a combination of treatments. In contrast, small cell lung cancer may only require chemotherapy and radiation therapy.
Targeted therapy is when doctors use drugs to block the growth of cancer cells to stop the spread. These targetted drugs can be in pill form or go through the veins. Chemotherapy for lung cancer can also be in pill form, through the veins, or even both. Radiation therapy uses high-energy rays to kill cancer cells, whereas surgery cuts out cancerous tissue.
Lung cancer is a complex and common cancer nationwide. There are many risk factors and causes, ranging from lifestyle choices, genetic variations, and more. The number one risk factor for developing lung cancer of any type is smoking cigarettes, cigars, and pipes. More research is necessary to determine risk factors that can make lung cancer progression more complex.
In most cases, it is possible to prevent lung cancer because so much of the disease is associated with lifestyle factors such as smoking. Eating a healthy diet and exercising may significantly decrease your risk of developing lung cancer and staying well. It is essential to be cautious of certain foods and high-dose supplements, as well as even alcohol and secondhand or passive smoke.
If you experience any of the symptoms above, be sure to reach out to a trusted healthcare provider to inquire about your treatment and even prevention options. Your doctor can help determine the best course of action for your unique case.