Though it is the most common cancer in the world and the leading cause of cancer-related deaths in the U.S.,2 early diagnosis, the ongoing development of promising medications, and increasing awareness of risk factors associated with it could help the death rate to decline.
Although many new medicines for the treatment of lung cancer have been approved in recent years, there may still be delays in access for patients, hospitals and doctors in some countries. There can be multiple factors that contribute to these delays such as market authorisation and bureaucratic delays.
Here are 10 things you need to know about lung cancer.
1. Lung cancer symptoms
Early-stage lung cancer is often symptomless, making it difficult for an early diagnosis. But as it progresses, some common symptoms arise, including the list below. This is by no means a complete list of symptoms. If you have any worries or cause for concern, always speak to your doctor without delay.
- A cough that doesn’t go away or gets progressively worse
- Fatigue or weakness
- Shortness of breath
- Chest pain that is often noticed when breathing, laughing or coughing
- Coughing up blood
- Development of bronchitis and/or pneumonia that doesn’t get better
- Loss of appetite
- Weight loss
If lung cancer spreads, other symptoms may emerge, such as:
- Jaundice (yellowing of the skin and eyes)
- Swollen lymph nodes or lumps under the skin
- Back or hip pain
- Nervous system problems: headaches, dizziness, arm or leg weakness, or seizures
2. There are two major types of lung cancer
These are; non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).
Approximately 85 to 90 percent of diagnosed lung cancers are NSCLC, and there are three types of these3:
- Adenocarcinoma: This cancer is most commonly found in current or former smokers. However, it is also the most common lung cancer found in non-smokers, is more common in women than in men, and more likely to develop in younger people than any other forms of lung cancer. Approximately 40 percent of lung cancers are adenocarcinomas.5 This cancer typically develops in the outer layers of the lungs, tends to grow slower than other forms, and has a greater chance of being found before it spreads to other areas.
- Squamous cell (epidermoid) carcinoma: These are often linked to smoking and develop within the inner airways of the lungs. Around 25 to 30 percent of lung cancers are squamous cell carcinomas.4
- Large cell (undifferentiated) carcinoma: This cancer can develop in any area of the lung and accounts for around 10 to 15 percent of lung cancer.6 It typically grows quickly and spreads fast, which makes it harder to treat.
- Small cell lung cancer
Small cell lung cancer (SCLC) and sometimes also called by its other name Oat Cell Cancer accounts for approximately 10 to 15 percent of all lung cancers and very rarely develops in someone who has not smoked.7 SCLC develops in the chest—usually in one part of the lung—and then typically spreads quickly through the rest of the body.
3. Lung cancer affects non-smokers, too
Though the greatest risk factor for lung cancer is smoking, approximately 10 to 15 percent of cases occur in non-smokers.8 This means that approximately 16,000 to 24,000 Americans who have never smoked die from lung cancer each year.9
Second-hand smoke is the third leading cause of lung cancer and has been found to increase a person’s risk “with the extent of exposure determining the associated risk,” according to Dr. Megan Baumgart, an assistant professor in the department of medicine, hematology/oncology at the Wilmot Cancer Institute in Rochester, New York.
Each year, 7,000 adults die from second-hand smoke.10 Those who live with a smoker or who are exposed to it in the workplace are at a 20 to 30 percent increased risk of developing lung cancer.11 In fact, if lung cancer in non-smokers was considered its own category, it would rank in the top 10 deadly cancers in the U.S.12
Laws that ban public smoking have helped to reduce the danger, and organizations such as the American Cancer Society Cancer Action Network are working to strengthen such laws.
4. Environmental factors
Radon gas is the number one cause of lung cancer in non-smokers, accounting for 21,000 deaths each year.13 This odorless, tasteless gas occurs in nature and is normally harmless; however, it can become concentrated within homes that are constructed in soil with uranium deposits. The only way to determine whether it exists in high levels within a home is to test for it.
Air pollution was designated a cancer-causing agent in 2013 by the World Health Organization. In the U.S., however, the risk of developing lung cancer due to air pollution is smaller than in other countries due to environmental policies.
Other environmental factors that increase the risk for lung cancer include exposure to asbestos, arsenic, tar, soot, chromium and nickel. Inflammation, most commonly caused by foods such as white bread and sugar-laden products, has also been found to be a contributing risk factor.
5. Screening could benefit high-risk cases
Though new screening techniques are being developed that aim to diagnose lung cancer in its earlier stages, current screening won’t typically prevent lung cancer from developing unless a person is considered high risk. High-risk people, according to the U.S. Preventive Services Task Force (USPSTF), are:
- Current smokers or smokers who quit within the past 15 years
- And who are 55 to 80 years old
- And have smoked at least one pack of cigarettes each day for 30 years or two packs a day for 15 years
For these smokers or former smokers, annual screenings with a low-dose CT scan (LDCT) can prevent a significant number of “lung-cancer-related deaths.”