Being told you have a high risk of lung cancer or being diagnosed with it can leave you with a lot of questions. There’s a great deal of information — and misinformation — out there, and it can be hard to make sense of it all.

Below are 30 facts and 5 myths about lung cancer: its causes, survival rates, symptoms, and more. Some of these facts might be things you already know, but some might be surprising.

1. Lung cancer is the most common type of cancer throughout the world.

In 2015, there were almost 1.7 million deaths worldwide from lung cancer.

2. In the United States, lung cancer is the second-most common type of cancer.

Prostate cancer is more common for men, while breast cancer is more common for women.

3. In 2017, there were an estimated 222,500 newly diagnosed cases of lung cancer in the United States.

4. However, the rate of new lung cancer cases has fallen an average of 2 percent a year over the last 10 years.

5. Early lung cancer might not cause any symptoms.

This means that lung cancer is often only caught in later stages.

6. A chronic cough is the most common symptom of early lung cancer.

This cough will probably get worse over time.

7. Tumors on the top of the lungs can affect facial nerves, causing symptoms like a dropping eyelid or not sweating on one side of your face.

This group of symptoms is called Horner’s syndrome.

8. Smoking is the leading cause of lung cancer.

Approximately 80 percent of lung cancer deaths result from smoking.

9. If you’re between 55 and 80 years old, smoked for at least 30 years, and either smoke now or quit less than 15 years ago, the U.S. Preventive Services Task Force recommends that you get yearly screenings for lung cancer.

The main type of screening used is a low-dose CT scan.

10. Even if you don’t smoke, being exposed to secondhand smoke can raise your risk of lung cancer.

Secondhand smoke causes around 7,000 lung cancer deaths per year.

11. Quitting smoking reduces your risk of lung cancer, even if you’ve smoked for a long time.

12. The second leading cause of lung cancer is radon, which is a naturally occurring gas.

Breathing it in exposes your lungs to small amounts of radiation. Radon can build up in your home, so radon testing is important.

13. African-American men are about 20 percent more likely than white men to get lung cancer.

However, the rate in African-American women is 10 percent lower than in white women.

14. Lung cancer risk increases as you get older.

Most cases are diagnosed in people over 60 years old.

15. To diagnose lung cancer, your doctor will use an X-ray or CT scan to see if you have a mass in your lungs.

If you do, they’ll probably do a biopsy to see if the mass is cancerous.

16. Doctors can do genetic tests on your tumor, which tells them the specific ways the DNA in the tumor has mutated, or changed.

This can help find a more targeted therapy.

17. There are many treatments for lung cancer.

These include chemotherapy, surgery, radiation therapy, radiosurgery, and targeted drug treatments.

18. There are four types of surgery for lung cancer.

In some cases, only the tumor and a small part of the tissue around it is removed. In others, one of the five lobes of the lung is removed. If the tumor is close to the center of the chest, you might need an entire lung removed.

19. Immunotherapy can be used to treat non-small cell lung cancer.

Immunotherapy is a type of treatment that blocks cancer cells from turning off a part of the immune system called T cells. When the T cells stay on, they recognize the cancer cells as “foreign” to your body and attack them. Immunotherapy for other types of lung cancer is currently being tested in clinical trials.

20. There are three types of lung cancer: non-small cell, small cell, and lung carcinoid tumors.

Non-small cell is the most common kind, accounting for about 85 percent of lung cancer.

21. Lung carcinoid tumors make up less than 5 percent of lung cancer cases.

22. Cancer stages tell you how far the cancer has spread.

Non-small cell lung cancer has four stages. In the first stage, cancer is only in the lungs. In the fourth stage, cancer has spread to both lungs, the fluid around the lungs, or to other organs.

23. Small cell lung cancer has two main stages.

The first is limited, where cancer is only in one lung. It might also be in some nearby lymph nodes. The second is extensive, where cancer has spread to the other lung, the fluid around the lungs, and potentially to other organs.

24. Lung cancer causes more cancer deaths than any other type of cancer, for both men and women.

It causes more deaths per year than colon, breast, and prostate cancers combined.

25. Age and sex can both affect survival rates.

In general, younger people and women have better survival rates.

26. Lung cancer deaths in the United States fell approximately 2.5 percent each year from 2005–2014.

27. If lung cancer is discovered before it spreads beyond the lungs, the five-year survival rate is 55 percent.

28. If cancer has already spread to other parts of the body, the five-year survival rate is 4 percent.

29. Research has found that in the first year after diagnosis, the average total cost of lung cancer spending on health care is around $150,000.

Most of this isn’t paid by the patients themselves.

30. World Lung Cancer Day is August 1.

1. You can’t get lung cancer if you don’t smoke.

Smoking causes most cases of lung cancer. However, exposure to radon, asbestos, other hazardous chemicals, and air pollution as well as secondhand smoke can also cause lung cancer. A family history of lung cancer can also increase your risk. In some cases of lung cancer, there are no known risk factors.

2. Once you’re a smoker, you can’t lower your risk of lung cancer.

Even if you’ve smoked for a long time, quitting smoking can decrease your risk of lung cancer. Your lungs might have some permanent damage, but quitting will keep them from becoming even more damaged.

Even if you’ve already been diagnosed with lung cancer, quitting smoking can help you respond better to treatment. Plus, quitting smoking is good for your health in a lot of ways. But if you smoked for a long time, you should get screened, even if you quit.

3. Lung cancer is always deadly.

Because lung cancer is often found in later stages, after it has already spread, it has a low five-year survival rate. But cancer in early stages is not only treatable, it’s even curable. And if your cancer isn’t curable, treatment can help extend your life and lessen your symptoms.

If you have any risk factors, talk to your doctor about screenings. These can help catch lung cancer earlier. You should also see your doctor if you have a cough that won’t go away and gets worse over time.

4. Exposing lung cancer to air or cutting it during surgery will cause it to spread.

Lung cancer does often spread to other parts of the lung, the lymph nodes near the lung, and to other organs. However, surgery does not cause any type of cancer to spread. Instead, cancer spreads because the cells in tumors grow and multiply without being stopped by the body.

Surgery can actually cure lung cancer in its early stages, when it’s localized to the lungs or a small amount of nearby lymph nodes.

5. Only older adults get lung cancer.

Lung cancer is much more common in people over 60 years old. However, that doesn’t mean that people under 60 never get it. If you’re currently 30 years old, for example, you have 0.16 percent chance of getting lung cancer over the next 20 years.

When you’re diagnosed with lung cancer, there’s a lot to learn and you have a lot of choices to make about your care. Work with your doctor to figure out what’s best for you. They’ll help you find the best course of treatment and can answer any other questions you might have. And if you’re a heavy smoker or have other risk factors for lung cancer, talk to your doctor about screenings and other preventive measures, including quitting smoking.