Non-Small Cell Lung Cancer: A Guide to Symptoms, Diagnosis, and Treatment

09 Nov 2023

8 Min. Read

Last updated on 25 Aug 2026

Lung cancer can develop when abnormal lung cells begin to grow and multiply uncontrollably. Smoking is a major risk factor, but it can also occur in people who have never smoked. In India, around 81,748 new cases of lung cancer were estimated in 2022.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for about 85% of cases. It includes several different types of cancer that can behave differently and may respond to different treatments.

Key Takeaways

NSCLC is the most common type of lung cancer.
Main types include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.
Smoking is the leading risk factor, but NSCLC can also occur in non-smokers.
Diagnosis usually involves imaging, biopsy, and molecular testing.
NSCLC is staged from 0 to IV based on how far it has spread.
Treatment may include surgery, radiation, chemotherapy, targeted therapy, or immunotherapy.
Molecular testing helps guide treatment, especially in advanced NSCLC.

What Is Non-Small Cell Lung Cancer?

Non-small cell lung cancer begins in lung tissue and does not have the features of small cell lung cancer. NSCLC develops when changes in lung cells cause them to grow and divide without control.

Lung cancer is broadly divided into two main types:

Non-small cell lung cancer (NSCLC)
Small cell lung cancer (SCLC)

NSCLC is more common than SCLC and includes several subtypes. NSCLC cells can carry different genetic changes so treatment can vary widely from person to person.

Main types of NSCLC

The three main types are:

Adenocarcinoma: This develops from glandular cells, including cells that line the alveoli. It is the most common type of NSCLC and can occur in people who have never smoked.

Squamous cell carcinoma: This begins in the thin, flat cells lining the airways. It has a strong association with smoking and often develops in the larger airways.

Large cell carcinoma: A less common type in which the cancer cells appear large and abnormal under a microscope.

Less common NSCLC subtypes include adenosquamous and sarcomatoid carcinomas.

Main Types of non-small cell lung cancer

What Causes Non-Small Cell Lung Cancer?

NSCLC develops because of changes in the DNA of lung cells. These changes can cause abnormal cells to grow and survive when they should not. Several factors can increase lung cancer risk.

Smoking

Tobacco smoking is the main risk factor for lung cancer. Cigarette smoke contains many substances that can damage lung cells and increase the chance of cancer-causing genetic changes.

The longer a person smokes and the more they smoke, the greater their risk. Stopping smoking lowers the risk over time, although people who have smoked remain at higher risk than people who have never smoked.

Other risk factors

NSCLC can also be associated with:

Second-hand tobacco smoke
Outdoor and household air pollution
Workplace exposure to asbestos, silica, diesel exhaust and certain chemicals
Radon exposure
Previous radiation exposure to the chest
Certain chronic lung conditions
A family history or genetic susceptibility to lung cancer

Not every person with NSCLC has a clear risk factor.

Symptoms of Non-Small Cell Lung Cancer

NSCLC may not cause noticeable symptoms in its early stages. Sometimes it is discovered unexpectedly during chest imaging performed for another reason.

Symptoms may include:

A persistent or worsening cough
Shortness of breath
Chest pain or discomfort
Wheezing
Coughing up blood
Hoarseness
Repeated chest infections
Difficulty swallowing
Unexplained weight loss
Loss of appetite
Persistent tiredness

Some symptoms appear when the tumour affects nearby structures. For example, nerve involvement can cause hoarseness, while pressure on the oesophagus can make swallowing difficult. In advanced NSCLC, symptoms can also develop when the cancer spreads to other parts of the body.

These symptoms can also occur with conditions that are not cancer. A persistent cough, coughing up blood, unexplained weight loss or ongoing breathing difficulty should still be assessed by a doctor.

How Is NSCLC Diagnosed?

Doctors use imaging, biopsy and other tests to confirm NSCLC and determine which treatment may be suitable.

Steps	What happens?
1. Imaging scans	A chest X-ray or CT scan looks for cancer in the lungs. PET-CT or MRI may check if it has spread.
2. Biopsy	A small sample of the tumour is examined under a microscope to confirm the cancer type.
3. Molecular tests	The tumour may be checked for gene changes such as EGFR, ALK, ROS1, BRAF, KRAS, MET, RET, NTRK and HER2. These results can help doctors choose targeted treatment.
4. PD-L1 test	This checks for a protein that can help doctors decide if certain immunotherapy medicines may be suitable.

Treatment of NSCLC

Treatment is based on the stage and type of NSCLC, along with the person's overall health.

Treatments	How it may be used
Surgery	Removes the cancer and is mainly used for earlier-stage NSCLC.
Radiation therapy	Uses radiation to destroy cancer cells. It may be used alone or with other treatments.
Chemotherapy	Uses medicines to kill cancer cells. It may be given before or after surgery or for advanced cancer.
Targeted therapy	Uses medicines that target specific changes in cancer cells, such as EGFR or ALK changes.
Immunotherapy	Helps the immune system recognise and fight cancer cells.

What happens after an NSCLC diagnosis depends on the stage, cancer type, molecular changes, overall health and response to treatment. Early-stage NSCLC may be curable. With advanced NSCLC, treatment usually focuses on controlling the cancer, extending survival and maintaining quality of life.

Reducing Your Risk and Planning Treatment

You cannot prevent every case of NSCLC, but some measures can lower your risk:

Avoid smoking and tobacco products.
Stop smoking if you currently smoke.
Avoid second-hand smoke.
Follow safety measures when working with asbestos, silica, diesel exhaust or other harmful substances.
Reduce exposure to household and outdoor air pollution where possible.
Check for radon exposure where it is a concern.

Stopping smoking is one of the most effective ways to reduce the risk of lung cancer. People at high risk may also be offered low-dose CT screening to look for lung cancer at an earlier stage. Screening is not recommended for everyone and depends on factors such as age, smoking history and overall risk.

Dr Navneet Singh, Professor of Pulmonary Medicine at PGIMER, Chandigarh, recommends considering biomarker testing when planning treatment for NSCLC. Testing can identify genetic changes or proteins in the tumour that may help doctors decide whether targeted therapy or immunotherapy is suitable.

For someone diagnosed with NSCLC, treatment can look very different from one person to another. The type and stage of cancer, molecular changes and overall health all matter. Speaking with a specialist and understanding the treatment options can help you make informed decisions about your care.

FAQs

Q1. What is non-small cell lung cancer?

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. It includes adenocarcinoma, large cell carcinoma, and squamous cell carcinoma.

Q2. What are the symptoms of non-small cell lung cancer?

Common symptoms include:

Persistent or worsening cough
Breathlessness
Chest pain
Coughing up blood
Hoarseness
Repeated chest infections
Unexplained weight loss or tiredness

Early NSCLC may cause no noticeable symptoms.

Q3. What causes non-small cell lung cancer?

Smoking is the main risk factor. Other non-small cell lung cancer causes include:

Second-hand smoke
Air pollution
Radon exposure
Asbestos and silica
Certain workplace exposures

Q4. How is non-small cell lung cancer diagnosed?

Non-small cell lung cancer diagnosis may involve:

Chest X-ray or CT scan
PET-CT or MRI when needed
Biopsy
Molecular and biomarker testing

Q5. What is non-small cell lung cancer radiology used for?

Radiology helps doctors find and assess a lung tumour and check whether it has spread. CT, PET-CT, and MRI may be used depending on the suspected stage and location of the cancer.

Q6. What are the stages of non-small cell lung cancer?

Non-small cell lung cancer stages range from 0 to IV. Earlier stages are limited to the lung, while later stages involve nearby structures, lymph nodes, or distant organs. Stage IV means the cancer has spread to distant parts of the body.

Q7. What is the difference between non-small cell and small cell lung cancer?

NSCLC and small cell lung cancer are different types of lung cancer. NSCLC is more common and includes several subtypes. Small cell lung cancer usually grows and spreads more quickly, and the two types are treated differently.

Q8. Is non-small cell lung cancer curable?

Some early-stage NSCLC can be cured, especially when the cancer can be completely removed or treated with local therapy. When NSCLC has spread, treatment usually focuses on controlling the cancer and helping people live longer.

Q9. What is the survival rate for non-small cell lung cancer?

There is no single survival rate for NSCLC. The outlook depends on the stage of the cancer, its type, molecular features, overall health and response to treatment. People diagnosed at an earlier stage generally have better outcomes.

Q10. What is the treatment for non-small cell lung cancer?

Treatment may include:

Surgery
Radiation therapy
Chemotherapy
Targeted therapy
Immunotherapy

The treatment chosen depends on the stage and type of NSCLC, molecular test results and the person's overall health.

References

Disclaimer: This article is intended for general information and educational purposes only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. Treatment decisions for non-small cell lung cancer should be made with a qualified cancer specialist based on the individual's diagnosis, stage, molecular test results and overall health.