Lung cancer is a type of cancer originating in one or both lungs, and is caused by mutations in the cells that lead to the growth of tumors. Smoking and regularly inhaling secondhand smoke dramatically increases your risk of developing the disease.
Lung cancer is the second most common type of cancer in the U.S., behind prostate cancer for men and breast cancer for women, and is the leading cause of cancer-related deaths. In 2017, it’s estimated that there will be 222,500 new cases of lung cancer, and about 155,870 deaths caused by the disease.
Lung Cancer Causes and Risk Factors
Lung cancer is usually caused by breathing in chemicals that affect the lungs and lead to mutations in the cells. Exposure to tobacco smoke is the most common cause, although other air pollutants can also lead to the disease.
Risk factors and causes of lung cancer include:
- Smoking: About 80% of lung cancer deaths stem from smoking tobacco. Smoking cigarettes, pipes, and cigars can all cause lung cancer, as well as cancers of the throat, mouth, stomach, and many other parts of the body.
- Secondhand smoke: Non-smokers can also develop lung cancer from exposure to tobacco smoke. Breathing in smoke exhaled by a smoker or from a lighted cigarette, pipe, or cigar is known as involuntary or passive smoking, and leads to about 7,000 lung cancer deaths each year.
- Radon: A radioactive gas, radon is produced by the breakdown of uranium in the earth. Radon exposure typically occurs indoors in concentrated locations and can lead to lung cancer. The EPA recommends periodically testing the radon levels in your home.
- Asbestos: Longterm exposure to asbestos can lead to lung cancer, as well as many other potentially fatal diseases, such as mesothelioma. Although there are many products that still contain asbestos in homes and public buildings across the U.S., exposure usually occurs in the workplace. Those who work in facilities with a history of using the contaminant (including mines, mills, and power plants) are especially at risk.
- Other carcinogens: A carcinogen is any substance that has been proven to cause cancer in cells. Known carcinogens include arsenic, diesel exhaust, and uranium, among others.
- Family history: People with family members who currently have or have had lung cancer are more likely to develop the disease than others. This risk is further increased by smoking.
- Radiation: Patients who previously had radiation therapy directed at the chest have a higher risk of developing lung cancer.
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Lung Cancer Prevention
Although there is no guaranteed way to prevent lung cancer, the best way to dramatically lower your risk of the disease is to stay away from tobacco.
While it’s best never to start smoking, quitting as soon as possible lowers your risk of developing cancer and other health complications, and allows damaged lung tissue to heal. Doctors recommend that people who have a history of smoking and are over the age of 55 get yearly screenings with a low-dose CT scan, since the risk of lung cancer remains higher in former smokers than in those who never smoked. Catching the disease early can lead to a better prognosis.
If you don’t smoke but find yourself around those who do, ask them to smoke outside, and don’t stand near them while they are smoking. Secondhand smoke is especially harmful to children, so if you or your partner smokes, consider seeking help quitting to protect your family’s health.
It’s wise to avoid any carcinogens, such as radon and arsenic. In addition to being linked to lung cancer, these chemicals can lead to other health issues. Radon is the second leading cause of lung cancer in the United States, causing an estimated 15,000 to 22,000 deaths each year. Ensure your home is tested regularly for radon, and carefully follow all safety advice when dealing with toxic chemicals, particularly if you encounter them regularly in your job.
A healthy diet that includes plenty of fruits and vegetables can also lower the risk of lung cancer and lead to a better quality of life.
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Symptoms of Lung Cancer
While many people know the most common symptoms of lung cancer, like coughing or wheezing, these symptoms are often mistaken for a less serious condition. In some cases, patients don’t experience any symptoms until the cancer has spread and become harder to treat. If you experience any of the following symptoms, particularly if you are a current or former smoker or live in a household with at least one smoker, speak to your doctor right away.
- Prolonged cough that may get worse over time
- Coughing up blood
- Chest pain impacting breathing, coughing, or laughing
- Shortness of breath
- Hoarse voice
- Weight loss
- Weakness or fatigue
- Recurring lung infections, like bronchitis or pneumonia
- Bone pain
- Bleeding or blood clots
Diagnosis and Types of Lung Cancer
A doctor will diagnose lung cancer by first screening using a CT, MRI, or PET scan, and then by taking a biopsy of lung tissue. The only way to confirm the presence of cancer is by analyzing the tissue using a biopsy procedure. Since symptoms of lung cancer can be associated with other diseases, the disease is hard to diagnose at an early stage.
Once diagnosed, the doctor will determine the type and stage of the cancer. There are two main types of lung cancer: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The types are determined by the formation of the cells. NSCLC is more common than SCLC, with almost 85% of cases being defined as non-small cell. SCLC is much rarer but spreads faster and is harder to treat.
Stages of Lung Cancer
Determining the stage of the lung cancer helps doctors to identify the proper course of treatment. NSCLC has the same staging system as most other cancers, ranking from stage I to stage IV based on extent the cancer has spread and its location in the body.
|Stage I||The lung cancer exists only in the lungs.|
|Stage IA||The cancer is up to three centimeters and is only in the lungs.|
|Stage IB||The cancer is between three and five centimeters and could be in the main bronchus, the membranes around the lungs, or partially clogging airways.|
|Stage II||The lung cancer is in the lungs and nearby lymph nodes.|
|Stage IIA||The cancer has a combination of traits, and could be three to seven centimeters, have grown into the main bronchus, have grown into the membranes around the lungs, partially clogging airways, or spread to nearby lymph nodes.|
|Stage IIB||The cancer is either between five and seven centimeters and spread through the lung and to nearby lymph nodes, or is larger than seven centimeters and spread through the lung but not to nearby lymph nodes.|
|Stage III||The lung cancer is in the lung, lymph nodes, and middle of the chest.|
|Stage IIIA||The affected lymph nodes are only on the side of the chest where the cancer originated.|
|Stage IIIB||The affected lymph nodes are on both sides of the chest or above the collarbone.|
|Stage IV||The cancer has spread to both lungs, fluid surrounding the lungs, and possibly to other parts of the body. This is the most aggressive and advanced form of lung cancer.|
Meanwhile, SCLC is grouped into the limited stage or the extensive stage.
- Limited stage: Cancer exists on one side of the chest in a localized part of the lung and nearby lymph nodes. This is similar to stages I and II.
- Extensive stage: Roughly equivalent to stage III and stage IV, the cancer has spread to other parts of the chest and the body.
Lung Cancer Survival Rates and Statistics
As the leading cause of cancer-related deaths in the U.S., lung cancer has a high mortality rate. About 14% of all cancer diagnoses are lung cancer, and the disease accounts for around one in every four cancer-related deaths.
Lung cancer survival rates are significantly higher when the disease is caught and treated while in the early stages. Unfortunately, many patients don’t experience symptoms until the cancer has progressed, making it much harder to treat. Overall, about 18.1% of people diagnosed with lung cancer survive five years after diagnosis.
|Non-small cell lung cancer (NSCLC)|
|Stage I A||49%|
|Small cell lung cancer (SCLC)|
2017 Lung Cancer Statistics
- The American Cancer Society estimates about 155,870 lung cancer deaths will occur in 2017
- Two out of three people diagnosed with lung cancer are over 65 years old.
- Men have a 1 in 14 chance of being diagnosed with lung cancer, while women have a 1 in 17 chance.
- Black men are about 20% more likely to develop lung cancer than white men.
Treatments and Therapies
Treatments for lung cancer depend on the type and the stage of the disease. Typically, doctors will recommend a combination of treatments. Treatment options include:
- Surgery: Operations to remove tumors may be an option for NSCLC patients that are in the early stages. It is very rare for SCLC to be diagnosed early enough for surgical operations to be effective.
- Chemotherapy: There are a number of possible drugs used to attack lung cancer cells in the body. Chemotherapy is commonly used for both types of lung cancer, specifically later stage cases where the cancer has spread throughout the body.
- Radiation: Doctors use radiation therapy to treat both NSCLC and SCLC cases, often combined with chemotherapy, or post-surgery. The treatment targets specific areas of the body.
- Targeted treatments: Advanced medical discoveries have led to the production of new drugs targeting cancer cells by inhibiting growth. At this point, doctors mainly use targeted drugs for advanced stages of NSCLC.
- Immunotherapy: Used to treat some patients with NSCLC, immunotherapy is a treatment that aims to make a person’s immune system attack cancerous cells. The two main immunotherapy medicines are nivolumab and atezolizumab.
Lung cancer is a difficult form of cancer to treat as it is often discovered in the later stages. To reduce your risk of lung cancer, maintain a healthy lifestyle and avoid tobacco smoke. For advice about quitting smoking, or if you notice any symptoms, speak to your doctor.