Lung cancer is one of the most common and most serious cancers worldwide, yet it is also an area where earlier detection and smarter testing are steadily improving outcomes. It begins when abnormal cells in the lungs grow out of control, often with no obvious warning signs in the early stages. Understanding how the disease develops, which symptoms deserve attention, and how doctors confirm it can help you act sooner and ask better questions at every step. In this article you will learn what lung cancer is, who is most at risk, how it is screened for and diagnosed, which treatments are used today, and how blood tests and biomarkers fit into the wider picture. The tone here is practical and reassuring: useful information, not alarm.
What is lung cancer?
Lung cancer is a disease in which cells lining the airways or the lung tissue itself multiply uncontrollably and form a tumor. Over time, these cells can crowd out healthy tissue, interfere with breathing, and in some cases spread to other parts of the body. Doctors sort the disease into two broad families that behave differently and are treated differently, which is why identifying the type early is so important.
The two main types
Non-small cell lung cancer (NSCLC) accounts for roughly 8 in 10 cases. It generally grows more slowly and includes subtypes such as adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Small cell lung cancer (SCLC) is less common but tends to grow and spread faster, and it is strongly associated with smoking. The type matters because it shapes the choice of treatment, the pace of care, and the tests your medical team will order. It also influences which biomarkers are worth measuring, a point we return to below.
What causes lung cancer, and who is at risk?
Smoking remains the single largest cause of lung cancer, responsible for the large majority of cases. But it is not the only cause, and a meaningful share of people diagnosed have never smoked. Risk builds gradually and reflects a mix of exposures, genetics, and age, so no single factor tells the whole story.
- Tobacco smoke, including current or past smoking and regular exposure to secondhand smoke.
- Radon, a naturally occurring radioactive gas that can accumulate indoors and is the leading cause among people who have never smoked.
- Workplace exposures such as asbestos, diesel exhaust, silica, and certain metals.
- Outdoor air pollution over many years.
- A family history of lung cancer, or previous radiation therapy to the chest.
- Older age and long-standing lung conditions such as chronic obstructive pulmonary disease (COPD).
Having one or more risk factors does not mean you will develop the disease, and some people with none still do. What risk factors help with is deciding who benefits most from screening, and reminding anyone who currently smokes that quitting lowers risk at any age.
Symptoms and early warning signs
Early lung cancer often causes no symptoms at all, which is exactly why screening matters for people at high risk. When symptoms do appear, they can be easy to mistake for a lingering cold, bronchitis, or a long-standing “smoker’s cough.” The signs below are common but non-specific, meaning many other conditions can produce them.
- A cough that lasts more than three weeks, or a change in a cough you have had for a long time.
- Coughing up blood, even a small amount or streaks in phlegm.
- Breathlessness or wheezing that is new or getting worse.
- Chest, shoulder, or back pain that is persistent, sometimes worse when breathing or coughing.
- A hoarse voice, repeated chest infections, or unexpected fatigue.
- Unexplained weight loss or loss of appetite.
Signs that are easy to overlook
Lung cancer can affect people who have never smoked, and symptoms in that group are sometimes brushed off for longer. In some cases the first clues come from cancer that has already spread, such as bone pain, headaches, or swelling in the neck or face. Because these symptoms overlap heavily with harmless conditions, they are not proof of cancer, but any that persist for more than two or three weeks deserve a medical review. To see how similar respiratory symptoms are investigated in very different conditions, you can read our article on pulmonary embolism, and consult our guide to asthma and chronic airway disease.
Wanneer moet je een arts raadplegen?
- You cough up blood, at any amount.
- A cough, chest pain, or breathlessness lasts more than two to three weeks.
- You have unexplained weight loss, marked fatigue, or repeated chest infections.
- You are at high risk because of your smoking history and have never discussed screening.
How lung cancer is diagnosed
No single test diagnoses lung cancer. Instead, doctors combine imaging, a tissue sample, and supporting laboratory work to confirm whether cancer is present, identify its type, and work out how far it has spread.
Imaging and biopsy
A chest X-ray is often the first step when symptoms appear, but it can miss small tumors. A CT scan gives a far more detailed view and can reveal nodules, their size, and nearby lymph nodes. If an area looks suspicious, the only way to confirm cancer is a biopsy, in which a small sample of tissue is taken, often through a thin tube passed into the airways (bronchoscopy) or with a needle guided by imaging. A PET scan may then be used to check whether the disease has spread, which helps determine the stage.
The role of blood tests and tumor markers
Blood tests do not diagnose lung cancer by themselves, but they play important supporting roles. Routine panels check your general health and fitness for treatment, and you can review onze gids over het volledig bloedbeeld to see what those numbers describe. Certain tumor markers, which are proteins that can rise when a tumor is active, are sometimes measured to help follow a known cancer over time rather than to find it in the first place. In lung cancer these can include CEA (carcinoembryonic antigen), CYFRA 21-1, NSE (neuron-specific enolase), and ProGRP, the last two being more useful in small cell disease. For background, explore our overview of tumor markers used in cancer careraadplegen, en bekijk onze gids over de CEA-bloedtest. An enzyme called LDH is also sometimes tracked, and you can consult onze gids voor de LDH-bloedtest.
One caution is worth repeating: tumor markers are not reliable screening tools for healthy people, because they can be normal in real cancers and raised by harmless conditions. They are most useful as a trend, interpreted alongside imaging and your symptoms. To go deeper, read our explainer on abnormal blood test results.
Lung cancer screening: who qualifies for a low-dose CT scan
Screening means testing people who feel well in order to find cancer early, when it is most treatable. For lung cancer, the recommended screening test is a low-dose CT scan, or LDCT, a quick scan that uses a small amount of radiation to create detailed images of the lungs. The U.S. Preventive Services Task Force gives this a grade B recommendation, and the U.S. Centers for Disease Control and Prevention echo the same eligibility.
Annual screening is recommended for adults who meet all three of the following conditions:
- Aged 50 to 80 years.
- Have a 20 pack-year smoking history or more. A pack-year means smoking an average of one pack a day for one year, so 20 pack-years could be one pack a day for 20 years, or two packs a day for 10 years.
- Currently smoke, or have quit within the past 15 years.
Screening can stop once a person has not smoked for 15 years, or if another health problem would limit life expectancy or the ability to have curative surgery. If you think you qualify, it is worth raising screening with your doctor, because finding lung cancer before symptoms appear is one of the clearest ways to improve the odds.
Biomarker and molecular testing: matching treatment to your tumor
When lung cancer is confirmed, especially non-small cell lung cancer, a sample of the tumor is often sent for biomarker or molecular testing. This looks for specific changes in the cancer’s genes or proteins that predict which treatments are most likely to work. It is one of the biggest shifts in lung cancer care over the past decade, moving treatment from one-size-fits-all toward choices tailored to each tumor.
- EGFR, ALK, and ROS1 are examples of gene changes that, when present, can be matched to specific targeted therapies.
- PD-L1 is a protein on tumor cells that helps estimate how well immunotherapy may work.
- Circulating tumor DNA, or ctDNA, can be measured in a blood sample in what is often called a “liquid biopsy,” which is useful when tissue is limited or to follow a cancer over time.
The table below summarizes how the main tests and markers fit together, from the first scan to the molecular details that guide treatment.
| Test or marker | Waar het naar kijkt | How it is typically used |
|---|---|---|
| Low-dose CT (LDCT) | Small nodules or masses in the lungs | Screening people at high risk; often the first imaging step |
| Biopsie | A small tissue sample from the tumor | Confirming the diagnosis and the exact cancer type |
| CEA and CYFRA 21-1 | Proteins that can rise with some tumors | Helping monitor a known cancer over time, not for screening |
| EGFR, ALK and ROS1 | Specific gene changes in the tumor | Matching the cancer to a targeted therapy |
| PD-L1 | A protein on the surface of tumor cells | Estimating how well immunotherapy may work |
| Circulerend tumor-DNA (ctDNA) | Tumor DNA fragments in a blood sample | A liquid biopsy to help detect changes or monitor treatment |
| Volledig bloedbeeld (CBC) | Red cells, white cells and platelets | Checking general health and readiness for treatment |
How lung cancer is treated
Treatment depends on the type of lung cancer, its stage, the biomarker results, and your overall health. Many people receive a combination of approaches, and plans are increasingly personalized rather than standard.
- Surgery removes the tumor and is most often used for early-stage non-small cell lung cancer.
- Radiation therapy uses targeted energy to destroy cancer cells, sometimes to cure early disease and sometimes to relieve symptoms.
- Chemotherapy uses medicines that kill fast-growing cells and remains a backbone in many situations, especially small cell lung cancer.
- Targeted therapy uses drugs that block a specific gene change, such as EGFR or ALK, and is chosen based on molecular testing.
- Immunotherapy helps the immune system recognize and attack the cancer, and is often guided by PD-L1 results.
Deciding among these options is a team effort, and biomarker results increasingly sit at the center of that conversation. That is why the testing described above is not a technicality: it can directly change which treatment you are offered.
Recente wetenschappelijke ontwikkelingen
Lung cancer research has moved quickly, and several recent developments are worth understanding in plain terms. None of the studies below is a reason to change your own care without talking to your doctor, but together they show where the field is heading.
Liquid biopsy is maturing
Reviews published in 2024 and 2025 describe how blood-based “liquid biopsy” tests, which look for tumor DNA fragments (ctDNA) in a simple blood draw, are increasingly used to help diagnose lung cancer, choose treatment, and watch for changes over time. What this means for you is that some information that once required a tissue biopsy may, in certain situations, come from a blood test instead. These tests are still being refined and do not yet replace imaging or tissue sampling, but they are a genuine and growing part of care.
Immunotherapy, guided by PD-L1
A 2022 overview in a leading oncology journal helped establish immunotherapy as a first-line option for many people with advanced non-small cell lung cancer. Since then, a 2024 systematic review and meta-analysis in JAMA Oncology, and a 2025 systematic review and meta-analysis, have examined giving immunotherapy before or around surgery. A meta-analysis pools many studies to see the overall pattern; these found that adding immunotherapy can improve how well tumors respond, with benefit influenced by PD-L1 levels. What this means for you is that a PD-L1 result is not just a number on a report, it can help your team judge whether immunotherapy is likely to help.
Targeted therapy after chemoradiotherapy
In a 2024 randomized controlled trial published in the New England Journal of Medicine, adding the EGFR-targeted drug osimertinib after chemoradiotherapy delayed the return of disease in people with unresectable stage III EGFR-mutated non-small cell lung cancer. A randomized controlled trial is a study that compares treatments fairly by assigning them at random. The practical takeaway is that knowing a tumor’s EGFR status can open the door to treatments matched to that specific change, which is exactly what molecular testing is for.
Lowering your risk
Not every case of lung cancer is preventable, but risk can be reduced. The most powerful step is not starting to smoke, or quitting if you do, because risk begins to fall soon after and keeps falling over the years. Testing your home for radon, limiting workplace and environmental exposures, and following screening advice if you qualify all add further protection. If you have already had a diagnosis, these same steps still support your overall health during and after treatment.
Glossarium
| Termijn | Definitie |
|---|---|
| NSCLC | Non-small cell lung cancer, the most common group of lung cancers, which tends to grow more slowly. |
| SCLC | Small cell lung cancer, a less common but faster-growing type strongly linked to smoking. |
| LDCT | Low-dose computed tomography, the recommended imaging test for lung cancer screening. |
| Biopsie | Removal of a small tissue sample so it can be examined for cancer cells. |
| Biomarker | A measurable feature of a tumor, such as a gene change or protein, that can guide treatment. |
| EGFR and ALK | Gene changes that, when found in a tumor, can be matched to specific targeted therapies. |
| PD-L1 | A protein on tumor cells used to estimate how well immunotherapy may work. |
| ctDNA (liquid biopsy) | Tumor DNA fragments detected in a blood sample, used to help diagnose or monitor cancer. |
| Pack-year | A way to measure smoking history: one pack a day for one year equals one pack-year. |
| Staging | Describing how large a cancer is and whether it has spread, which guides treatment. |
Veelgestelde vragen
What are the first signs of lung cancer?
Early lung cancer frequently causes no symptoms, which is why screening matters for high-risk groups. When signs do appear, the most common are a cough lasting more than three weeks, a change in a long-standing cough, breathlessness, chest pain, or coughing up blood. Because these overlap with many minor illnesses, they are not proof of cancer, but persistent symptoms should always be checked by a doctor.
Kan longkanker genezen worden?
Some lung cancers can be cured, and the chance is highest when the disease is found early and can be removed with surgery or treated with focused radiation. More advanced lung cancer may not be curable in every case, but modern targeted therapies and immunotherapy can control it for longer and improve quality of life. Outcomes vary widely from person to person, so your care team is the best source for what is realistic in your situation.
Is lung cancer screening only for people who smoke?
Screening with a low-dose CT scan is currently recommended for adults aged 50 to 80 who have a substantial smoking history and either still smoke or quit within the past 15 years. People who have never smoked are not routinely screened, because the benefit has not been shown for lower-risk groups. If you are unsure whether you qualify, your doctor can review your history and explain the pros and cons.
Can you have lung cancer with a normal chest X-ray or blood test?
Yes. A chest X-ray can miss small tumors, and there is no blood test that reliably rules lung cancer in or out on its own. This is why a low-dose CT scan is used for screening rather than an X-ray or a blood panel, and why any persistent symptoms deserve follow-up even if earlier tests looked normal.
What do biomarkers like EGFR and PD-L1 actually change?
Biomarkers describe the biology of a specific tumor. Finding a change such as EGFR or ALK can mean a targeted therapy is available, while a PD-L1 result helps predict how useful immunotherapy may be. In practice, these tests can directly change which treatment you are offered, which is why they are now a standard part of diagnosing non-small cell lung cancer.
What is the survival rate for lung cancer?
Survival depends heavily on the type, the stage at diagnosis, biomarker results, and overall health, so a single number can be misleading. In general, lung cancer found early has a much better outlook than lung cancer found after it has spread, which is the main reason screening and prompt evaluation of symptoms matter so much. Your medical team can give figures that fit your particular diagnosis.
Bronnen
- U.S. Preventive Services Task Force. Lung Cancer: Screening (Grade B recommendation), 2021. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/lung-cancer-screening
- Centers for Disease Control and Prevention. Lung Cancer Screening. https://www.cdc.gov/lung-cancer/screening/index.html
- National Cancer Institute. Non-Small Cell Lung Cancer Treatment (PDQ) — Patient Version. https://www.cancer.gov/types/lung/patient/non-small-cell-lung-treatment-pdq
- Ma L, et al. Liquid biopsy techniques and lung cancer: diagnosis, monitoring and evaluation. Journal of Experimental & Clinical Cancer Research, 2024. https://doi.org/10.1186/s13046-024-03026-7
- A Review of Circulating Tumor DNA (ctDNA) and the Liquid Biopsy in Cancer Diagnosis, Screening, and Monitoring Treatment Response. Medical Science Monitor, 2025. https://doi.org/10.12659/MSM.949300
- Neoadjuvant Chemoimmunotherapy for NSCLC: A Systematic Review and Meta-Analysis. JAMA Oncology, 2024. https://doi.org/10.1001/jamaoncol.2024.0057
- Efficacy of neoadjuvant, adjuvant, and perioperative immunotherapy in non-small cell lung cancer across different PD-L1 expression levels: a systematic review and meta-analysis. Frontiers in Immunology, 2025. https://doi.org/10.3389/fimmu.2025.1569864
- Reck M, et al. First-Line Immunotherapy for Non-Small-Cell Lung Cancer. Journal of Clinical Oncology, 2022. https://doi.org/10.1200/JCO.21.01497
- Osimertinib after Chemoradiotherapy in Stage III EGFR-Mutated NSCLC. New England Journal of Medicine, 2024. https://doi.org/10.1056/NEJMoa2402614
Verder lezen
- Colorectal cancer: causes, symptoms, and treatments
- Stomach cancer: causes, symptoms, and treatments
- Pancreatic cancer: understanding, diagnosing, and treating it
- Breast cancer: understanding, treatment, and prevention
- Read your blood test results: a simple guide
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A lung cancer diagnosis brings a flood of numbers, from a complete blood count to tumor markers such as CEA and molecular results like EGFR, ALK, and PD-L1. AI DiagMe helps you understand what these lab values mean in plain language, so you can walk into appointments with clearer questions. It is designed to help you understand your results, not to diagnose you, and it never replaces the judgment of your own doctor.
