TL;DR:

• Lung cancer is the top cause of cancer death worldwide.
  
• Smoking, radon, and air pollution drive most risk.
  
• A new cough, chest pain, or weight loss needs medical review.
  
• Yearly low dose CT helps high risk adults find cancer early.
  
• Quitting tobacco and testing homes for radon save lives.
  

The plain-English guide to lung cancer

Lung cancer is common and deadly, yet many deaths are preventable. It is the leading cause of cancer death in the world. Most cases link to smoking, but nonsmokers can be affected by radon, air pollution, and workplace exposures. The goal of this guide is simple. Know your risks, spot warning signs, and learn what to do next.

All facts are current as of 2025-10-10.

What lung cancer is

Lung cancer starts when cells in the lungs grow in an uncontrolled way. There are two broad groups.

• Non small cell lung cancer, the most common group. It includes adenocarcinoma and squamous cell carcinoma.
  
• Small cell lung cancer, which grows and spreads faster.
  

Doctors confirm the type with a biopsy. Treatment depends on stage, type, and tumor genetics.

How common it is

Global data show the scale. In 2022, there were about 2.48 million new cases worldwide, with lung cancer the leading cause of cancer death. These estimates come from the International Agency for Research on Cancer. The World Health Organization also lists lung cancer among the most diagnosed cancers and a top cause of cancer death. These numbers explain why screening and prevention matter.

Key risk factors

Smoking and tobacco

Cigarette smoking causes most lung cancers. The risk rises with years smoked and packs per day. Quitting lowers risk over time. People who smoke should seek help to quit with counseling plus medicines or nicotine replacement. Heated tobacco and e-cigarettes are not safe alternatives.

Radon

Radon is a natural radioactive gas that seeps into buildings from soil and rock. It is invisible and odorless. It is the second leading cause of lung cancer overall and the top cause in people who never smoked. Every home can be tested with a simple kit. If levels are high, certified contractors can fix it with ventilation systems.

Action step: If you live in a high radon area or have a basement or ground-level home, order a radon test. Retest after big renovations and after mitigation.

Outdoor air pollution

Long term exposure to outdoor air pollution, especially fine particulate matter, raises lung cancer risk. Risk is higher near busy roads, industrial zones, and wildfire smoke. City and national policies that cut emissions help. On bad air days, limit outdoor exertion, use indoor air cleaners with HEPA filters, and seal windows as advised by local health agencies.

Work exposures

Asbestos, diesel exhaust, silica, arsenic, and certain metals raise risk. Use proper protective equipment and follow safety rules at work. If you had high exposure in the past, tell your clinician.

Other factors

Family history, prior chest radiation, and some lung scarring disorders add risk. HIV and some immune conditions may also increase risk.

Symptoms to take seriously

Many early lung cancers cause no symptoms. When symptoms appear, common ones include:

• A cough that lasts more than three weeks.
  
• Coughing up blood, even small amounts.
  
• Chest pain or shoulder pain that worsens with deep breaths.
  
• Shortness of breath or wheeze that is new.
  
• Recurrent chest infections.
  
• Unexplained weight loss, fatigue, or appetite loss.
  
• Hoarseness or new bone pain.
  

Do not wait for all symptoms to appear. One persistent warning sign is enough to seek care.

Who should get screened

Low dose computed tomography, or LDCT, can find lung cancer early in people with high risk. Early detection improves the chance of cure.

Two leading groups publish guidance that many countries use when setting local rules.

• United States Preventive Services Task Force (USPSTF). Annual LDCT for adults aged 50 to 80 who have a 20 pack-year smoking history and who smoke now or quit within the past 15 years. Stop when a person has not smoked for 15 years or is not a candidate for curative treatment.
  
• American Cancer Society (ACS). Annual LDCT for adults aged 50 to 80 with a 20 pack-year history who smoke now or used to smoke. The ACS does not apply a “years since quitting” limit. Insurance coverage may still follow USPSTF rules in some systems.
  

Outside the United States, programs differ. The United Kingdom is building a national lung cancer screening program based on targeted invites for high risk adults, with nationwide rollout planned over the coming years. Check your country’s health ministry or cancer society for local eligibility and how to enroll.

What a screening visit looks like

• Risk review. Your team will confirm your smoking history and health status.
  
• The scan. LDCT takes a few minutes, uses no contrast, and exposes you to a low radiation dose.
  
• Results and next steps. Most scans are normal or show small nodules that need short term follow up. A small share need further imaging or a biopsy.
  

Screening is for people without symptoms. If you have symptoms, see a clinician now rather than waiting for a routine screen.

How doctors diagnose and stage

If a scan finds a suspicious spot, the next steps may include:

• Repeat CT, PET-CT, or MRI to define size and spread.
  
• A biopsy with bronchoscopy, needle, or surgery.
  
• Lab tests on the tumor to identify markers, such as EGFR, ALK, ROS1, KRAS, and PD-L1.
  

Staging describes how far the cancer has spread. Stages I and II are early. Stage III is locally advanced. Stage IV is metastatic.

Treatment at a glance

Treatment plans are tailored in a multidisciplinary team. Common parts include:

• Surgery. For early stages, removing the tumor can be curative.
  
• Stereotactic body radiotherapy. A precise option for some early cancers when surgery is not possible.
  
• Chemotherapy. Often used with other treatments or for advanced disease.
  
• Targeted therapy. Pills or infusions that attack specific mutations, such as EGFR or ALK.
  
• Immunotherapy. Drugs that help the immune system attack cancer, often targeting PD-1 or PD-L1.
  
• Palliative care. Symptom relief and support at any stage, alongside active treatment.
  

Clinical trials offer access to new therapies. Ask if a trial fits your situation.

Proven ways to lower your risk

Quit tobacco

Quitting at any age helps. Benefits start within weeks. Use a mix of strategies:

• Brief counseling from a clinician.
  
• Nicotine replacement therapy, such as patches and gum.
  
• Prescription medicines like varenicline or bupropion, when appropriate.
  
• Support lines and text programs.
  
• Removing triggers and setting a clear quit date.
  

Test for radon

Buy a do-it-yourself radon test kit or hire a certified tester. If levels exceed your country’s action level, install mitigation. Combine this with smoking cessation for the biggest risk drop.

Reduce air pollution exposure

Follow local air quality alerts. On poor air days, limit outdoor workouts, close windows, and run a HEPA purifier if you have one. Support clean transport and energy policies in your community.

Protect your lungs at work

Use respirators and other protective gear as required. Get regular occupational health checks if your job involves known lung hazards.

Stay current on vaccines and screenings

Vaccines that prevent respiratory infections can help protect fragile lungs during treatment. People with smoking history should also stay up to date on other age-appropriate cancer screenings.

A quick checklist

Common questions

Is LDCT safe?
Yes, the radiation is low. The benefit outweighs risk for people who meet criteria.

If I quit 20 years ago, should I still screen?
Under ACS guidance, you may still be eligible. Under USPSTF rules, you may not. Coverage and local policies vary. Ask your clinician.

Can diet or supplements prevent lung cancer?
No supplement prevents lung cancer. A diet rich in fruits, vegetables, whole grains, and fish supports overall health but is not a replacement for quitting tobacco or reducing exposure.

Do air purifiers help?
HEPA purifiers reduce indoor particulate levels. They cannot remove gases like radon, but they help on bad air days.

Why it matters

Most lung cancer deaths are linked to known, fixable risks. Quitting tobacco, testing homes for radon, and using LDCT for the right people can save many lives. Small steps, started today, add up to real gains for families and communities.

[Related: How to pick a HEPA air purifier → /home/hepa-guide]
[Related: Stop smoking plan that works in 30 days → /quit-tobacco/30-day-plan]
[Related: What to expect at your first LDCT → /screening/ldct-first-visit]

Sources:

• World Health Organization, Lung cancer fact sheet, https://www.who.int/news-room/fact-sheets/detail/lung-cancer, updated 2023-06-26.
  
• International Agency for Research on Cancer, Global lung cancer incidence and subtype press release, https://www.iarc.who.int/wp-content/uploads/2025/02/pr359_E.pdf, published 2025-02-03.
  
• Global Cancer Observatory, World fact sheet (GLOBOCAN 2022), https://gco.iarc.who.int/media/globocan/factsheets/populations/900-world-fact-sheet.pdf, accessed 2025-10-10.
  
• WHO, Cancer fact sheet, https://www.who.int/news-room/fact-sheets/detail/cancer, updated 2025-02-03.
  
• USPSTF, Lung cancer screening recommendation, https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/lung-cancer-screening, published 2021-03-09.
  
• American Cancer Society, Lung cancer screening guidelines, https://www.cancer.org/health-care-professionals/american-cancer-society-prevention-early-detection-guidelines/lung-cancer-screening-guidelines.html, updated 2023-11-01.
  
• UK National Screening Committee and NHS, Lung cancer screening programme updates, https://nationalscreening.blog.gov.uk/2025/01/31/targeted-lung-health-check-programme-renamed-the-nhs-lung-cancer-screening-programme/ and https://www.nhs.uk/tests-and-treatments/lung-cancer-screening/, accessed 2025-10-10.
  
• WHO, Radon and health fact sheet, https://www.who.int/news-room/fact-sheets/detail/radon-and-health, updated 2023-01-25.
  
• IARC, Outdoor air pollution classified as carcinogenic to humans, https://www.iarc.who.int/news-events/iarc-outdoor-air-pollution-a-leading-environmental-cause-of-cancer-deaths/, published 2013-10-17.