Lung Cancer: Symptoms, Diagnosis, and Treatment

What Is Lung Cancer?

Lung cancer is a malignancy that begins in the cells of the lung — usually the airways or air sacs. It is the leading cause of cancer death globally and in Australia, accounting for more deaths than any other cancer type. Most cases are diagnosed at an advanced stage, when the cancer has already spread, because early-stage lung cancer rarely causes symptoms.

The two main categories — non-small cell and small cell — behave differently and are treated differently. Understanding the type and stage of a lung cancer is the essential first step before any treatment decisions are made.

This guide covers what lung cancer is, how it develops, what to watch for, how it is diagnosed and staged, what treatment involves, and what to expect when living with the diagnosis.

Key Points

Lung cancer is the leading cause of cancer death worldwide.
Most cases are diagnosed at an advanced stage because early-stage disease rarely causes symptoms.
Smoking is the most significant risk factor — but lung cancer also occurs in people who have never smoked.
Non-small cell lung cancer (NSCLC) accounts for approximately 85% of cases; small cell lung cancer (SCLC) accounts for most of the remainder.
Molecular (biomarker) testing of the tumour now guides treatment choice — targeted therapies and immunotherapy are available for specific tumour subtypes.
Low-dose CT (LDCT) screening is recommended for people with a significant smoking history who meet age and pack-year eligibility — but is not appropriate for the general population.
Treatment options include surgery, radiotherapy, chemotherapy, immunotherapy, targeted therapy, and palliative/supportive care.
Early-stage disease has substantially better outcomes than advanced disease.
Persistent cough, coughing up blood, unexplained weight loss, or worsening breathlessness warrant prompt medical review.

Types of Lung Cancer

Non-Small Cell Lung Cancer (NSCLC)

Non-small cell lung cancer accounts for approximately 85% of all lung cancers. It includes three main histological subtypes:

Subtype	Features
Adenocarcinoma	Most common NSCLC subtype; arises in glandular cells; most common in non-smokers and women; frequently found peripherally in the lung; most likely to harbour targetable mutations (EGFR, ALK, KRAS)
Squamous cell carcinoma	Arises in the flat cells lining the airways; strongly associated with smoking; tends to occur centrally near larger airways
Large cell carcinoma	A less common subtype defined by exclusion; tends to grow and spread quickly

NSCLC grows relatively more slowly than small cell lung cancer and is more likely to be localised at diagnosis. Surgery and radiotherapy can be curative in early-stage disease.

Small Cell Lung Cancer (SCLC)

Small cell lung cancer accounts for approximately 15% of lung cancers and is almost exclusively associated with smoking. It grows rapidly and spreads early — most people are diagnosed at an extensive stage. SCLC is initially very responsive to chemotherapy but relapses quickly in most cases. Treatment is primarily chemotherapy and immunotherapy; surgery is rarely an option.

Molecular Testing

Molecular (biomarker) testing of the tumour is now a standard part of treatment planning for NSCLC. The tumour tissue is analysed for specific genetic changes — mutations, fusions, or gene amplifications — that can be targeted with matched drugs:

EGFR mutation — targeted by osimertinib and other EGFR inhibitors
ALK fusion — targeted by alectinib and other ALK inhibitors
KRAS G12C mutation — targeted by sotorasib, adagrasib
ROS1 fusion, MET amplification, BRAF, RET, NTRK — each with targeted options
PD-L1 expression — guides use of immunotherapy (pembrolizumab and others)

Treatment planning for advanced NSCLC requires knowing the molecular profile of the tumour. This is one reason why biopsy and pathology are so important.

Symptoms

Lung cancer symptoms are often absent in early-stage disease. When symptoms do occur, they commonly include:

Respiratory symptoms:

A persistent cough — new, or a significant change in a pre-existing cough
Coughing up blood (haemoptysis) — even small amounts warrant urgent evaluation
Shortness of breath — gradual worsening, or breathlessness on exertion
Chest pain — persistent, dull ache or sharp discomfort in the chest
Recurrent chest infections — pneumonia or bronchitis that keeps coming back

Systemic (whole-body) symptoms:

Unexplained weight loss
Persistent fatigue
Loss of appetite
Hoarseness or a change in voice

Symptoms from spread:

Bone pain (particularly back or hip) if cancer has spread to bone
Headaches, visual changes, or new neurological symptoms if spread to the brain
Swelling of the face or arms (superior vena cava syndrome — a medical emergency)
Persistent shoulder pain (Pancoast tumour at the lung apex)

Many of these symptoms overlap with other conditions — particularly COPD, asthma, chest infections, and heart conditions. Persistent or unexplained symptoms, particularly in a current or former smoker, warrant medical review.

Risk Factors

Smoking

Cigarette smoking is the single most important risk factor for lung cancer, responsible for approximately 85% of cases in high-income countries. Risk is related to cumulative exposure — how many cigarettes smoked per day and for how many years. People who quit smoking substantially reduce their future lung cancer risk, though risk remains elevated compared to never-smokers for many years after quitting.

See: Smoking Cessation — Methods, Support, and What Actually Works

Second-Hand Smoke

Regular exposure to other people’s cigarette smoke increases lung cancer risk. Non-smokers who live with a smoker have a higher risk than those with no household exposure.

Radon Gas

Radon is a naturally occurring radioactive gas that can accumulate in buildings, particularly in basements or poorly ventilated lower floors. It is the leading cause of lung cancer in non-smokers in some countries. Testing is available and remediation (improving building ventilation) reduces exposure.

Occupational Exposures

Long-term workplace exposure to certain substances increases lung cancer risk:

Asbestos — particularly in combination with smoking; causes mesothelioma and lung adenocarcinoma
Silica dust (mining, construction)
Diesel exhaust
Chromium, nickel, arsenic (in certain industrial processes)
Polycyclic aromatic hydrocarbons (PAHs — combustion-related exposures)

Occupational history is an important part of risk assessment for lung cancer.

Air Pollution

Outdoor air pollution — particularly fine particulate matter (PM2.5) from traffic and industrial sources — is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Long-term exposure increases lung cancer risk in both smokers and non-smokers.

Family History and Genetic Factors

Having a first-degree relative with lung cancer modestly increases individual risk, independent of smoking. Rare hereditary lung cancer syndromes exist but account for a very small proportion of cases.

Prior Lung Disease

People with COPD, pulmonary fibrosis, or a history of tuberculosis have a higher baseline lung cancer risk. Lung cancer and COPD frequently co-exist because they share common causes.

Prior Radiation

People who have previously received radiotherapy to the chest — for example, as part of treatment for another cancer — have an elevated risk of radiation-related lung cancer. This risk is relevant decades after the original treatment.

Screening

Screening aims to detect lung cancer at an early, more treatable stage in people who are at elevated risk — before symptoms develop.

Low-dose CT (LDCT) is the only lung cancer screening method with demonstrated mortality reduction. Major guidelines (including USPSTF 2021) recommend annual LDCT for adults with a significant smoking history who meet age and pack-year eligibility criteria.

The purpose of screening is different from diagnosis:

Screening — done in people at higher risk with no symptoms, to detect cancer early
Diagnosis — done after symptoms appear or an abnormal result occurs

See: Lung Cancer Screening: Low-Dose CT, Benefits, Risks, and Eligibility

Who should consider screening: Adults aged 50–80 with a smoking history of 20 or more pack-years who currently smoke or have quit within the past 15 years. Screening is not appropriate for people outside these criteria without specific guidance from a clinician.

Diagnosis

Initial Assessment

A GP or specialist will take a clinical history, examine you, and arrange initial tests. This usually starts with:

Chest X-ray — may detect an abnormality but misses many early lung cancers; a normal chest X-ray does not rule out lung cancer if symptoms are persistent
CT scan of the chest — the main imaging tool for evaluating a suspected lung mass; more sensitive than X-ray and better defines tumour size, location, and lymph node involvement

Further Imaging

PET-CT scan — a PET scan combined with CT; detects metabolic activity and helps stage the cancer by identifying spread to lymph nodes or distant sites
MRI of the brain — used in staging to assess for brain metastases in selected patients
Bone scan — sometimes used to detect bone metastases if not covered by PET

Tissue Diagnosis (Biopsy)

A definitive diagnosis requires examining cancer cells under a microscope. This is done through biopsy, which may be obtained by:

Bronchoscopy — a thin flexible camera inserted through the mouth or nose into the airways to visualise and sample tissue from central tumours; endobronchial ultrasound (EBUS) extends reach to lymph nodes
CT-guided needle biopsy — a needle inserted through the chest wall, guided by CT imaging, to sample peripheral tumours
Surgical biopsy (VATS) — video-assisted thoracoscopic surgery; used when other biopsy methods cannot reach the lesion
Pleural fluid sampling — if there is fluid around the lung (pleural effusion), testing the fluid may confirm malignancy

Pathology and Molecular Testing

Once tissue is obtained, the pathologist determines the histological type (NSCLC vs SCLC; adenocarcinoma vs squamous) and performs molecular testing — looking for targetable mutations, fusions, and gene expression markers (PD-L1). This information is essential for selecting the most appropriate treatment in NSCLC.

Staging

Staging describes how far the cancer has spread and is the foundation for treatment decisions.

NSCLC Staging (TNM system, plain language)

Stage	Description	Typical Treatment Approach
Stage I	Tumour confined to the lung	Surgery or stereotactic radiotherapy (curative intent)
Stage II	Tumour with nearby lymph node involvement or larger size	Surgery + chemotherapy; radiotherapy in some cases
Stage III	Spread to lymph nodes in the chest (locally advanced)	Chemotherapy + radiotherapy; surgery in selected cases
Stage IV	Spread to the other lung, pleura, or distant organs (metastatic)	Systemic therapy (targeted therapy, immunotherapy, chemotherapy); palliative care

SCLC Staging

SCLC is typically staged as:

Limited stage — cancer confined to one side of the chest (may be treated with chemotherapy and radiotherapy)
Extensive stage — cancer spread beyond the chest or to both lungs (treated with chemotherapy and immunotherapy)

Approximately two-thirds of SCLC cases are extensive stage at diagnosis.

Treatment

Treatment depends on the cancer type, stage, molecular test results, overall health, and the person’s preferences and goals of care. A multidisciplinary team (MDT) — including thoracic surgeons, oncologists, radiologists, pathologists, and palliative care — reviews each case before treatment is recommended.

Surgery

Surgery is the treatment of choice for early-stage NSCLC when the tumour can be completely removed. Options include:

Lobectomy — removal of the affected lobe of the lung; the standard surgical approach
Segmentectomy or wedge resection — removal of a smaller portion of lung; used when full lobectomy is not possible
Pneumonectomy — removal of the entire lung; reserved for selected cases

Surgery requires adequate lung function and general fitness. Pulmonary function tests help determine whether the remaining lung can support normal breathing.

Radiotherapy

Stereotactic ablative radiotherapy (SABR/SBRT) — delivers precise high-dose radiation to early-stage tumours; an effective alternative to surgery for people who cannot have an operation
Concurrent chemoradiotherapy — combines chemotherapy with radiotherapy for locally advanced (Stage III) NSCLC; the standard treatment when surgery is not appropriate
Palliative radiotherapy — lower-dose treatment to relieve symptoms from advanced cancer (bone pain, breathlessness from airway obstruction)

Chemotherapy

Chemotherapy uses drugs that target rapidly dividing cells. In lung cancer it is used:

Adjuvant chemotherapy — after surgery in Stage II–IIIA NSCLC to reduce recurrence risk
In combination with radiotherapy — for locally advanced disease
As systemic treatment — for advanced NSCLC or SCLC, often combined with immunotherapy
As first-line treatment — for SCLC (etoposide + carboplatin or cisplatin)

Immunotherapy

Immunotherapy drugs (checkpoint inhibitors — pembrolizumab, nivolumab, atezolizumab, durvalumab) block the mechanisms cancer cells use to avoid immune detection. They are now a standard part of treatment for many advanced NSCLC cases, either alone or combined with chemotherapy. Eligibility depends on PD-L1 expression and the absence of targetable mutations.

Targeted Therapy

For NSCLC with a targetable molecular alteration, specific drugs may be substantially more effective than standard chemotherapy:

EGFR-mutated NSCLC: osimertinib (Tagrisso), erlotinib, gefitinib
ALK-rearranged NSCLC: alectinib, brigatinib, lorlatinib
KRAS G12C-mutated NSCLC: sotorasib, adagrasib
Other targets (ROS1, MET, BRAF, RET, NTRK): multiple approved agents depending on the specific alteration

Targeted therapy is oral medication taken daily. It is not appropriate without molecular testing confirming the relevant mutation.

Palliative and Supportive Care

Palliative care is specialised support focused on symptom relief and quality of life. It is appropriate at any stage of lung cancer — not only at end of life. Palliative care helps manage breathlessness, pain, fatigue, nausea, and emotional distress. It can be delivered alongside cancer-directed treatment. Referral to a palliative care team early in the course of advanced lung cancer is associated with better quality of life and, in some studies, improved survival.

Living with Lung Cancer

Breathlessness

Breathlessness is one of the most common and distressing symptoms of lung cancer. It may be caused by the tumour itself, pleural effusion, anaemia, or treatment side effects. Management includes:

Breathing exercises and positions (sitting forward, pursed-lip breathing)
Oxygen therapy when indicated
Opioid medications (low-dose opioids reduce breathlessness safely in advanced disease)
Pleural drainage for effusion
Referral to palliative care for specialist symptom management

Fatigue

Cancer-related fatigue affects most people with lung cancer. It is different from ordinary tiredness — it is not relieved by rest and can be severe. Strategies include pacing activity, maintaining as much gentle exercise as tolerated, treating anaemia if present, and addressing sleep disruption.

Nutrition

Lung cancer and its treatment can affect appetite and weight. Maintaining nutritional intake supports treatment tolerance and recovery. A dietitian can provide personalised support, including managing swallowing difficulties or treatment-related nausea.

Cough Management

A persistent cough is distressing and may be difficult to fully control. Options include cough suppressants, humidified air, treating reversible causes (infection, reflux), and specialist cough physiotherapy. For cough caused by pleural effusion, drainage may provide relief.

Emotional and Psychological Support

A lung cancer diagnosis causes significant psychological distress for most people and their families. Anxiety, depression, grief, and uncertainty about the future are common. Support from:

Clinical psychologists or counsellors attached to cancer services
Cancer support groups and peer networks
Lung cancer helplines and patient advocacy organisations
Palliative care teams skilled in emotional support

should be offered alongside physical care. Partners, carers, and family members may also need their own support.

When to Seek Urgent Help

Go to an emergency department or call emergency services for:

Coughing up a significant amount of blood
Sudden or severely worsening shortness of breath at rest
Chest pain that is severe, new, or worsening
Swelling of the face, neck, or arms — particularly with a feeling of fullness in the head (may indicate superior vena cava syndrome)
Sudden confusion, severe headache, or new neurological symptoms (weakness, loss of speech)
Fainting or collapse
High fever with chills, particularly if you are on chemotherapy (possible neutropenic sepsis — a medical emergency)
Rapid worsening of any symptoms over hours to a day

Contact your cancer team promptly for any concerning changes in your condition between scheduled appointments.

FAQ

Q: What are common symptoms of lung cancer? Common symptoms include a persistent cough, coughing up blood, chest pain, shortness of breath, recurrent chest infections, unexplained weight loss, fatigue, and hoarseness. Many early lung cancers cause no symptoms at all.

Q: Can people who have never smoked get lung cancer? Yes. While smoking is the biggest risk factor, lung cancer also occurs in never-smokers. Radon exposure, asbestos, air pollution, and genetic factors also contribute.

Q: How is lung cancer diagnosed? Diagnosis usually begins with imaging (chest X-ray, CT scan) and is confirmed by biopsy — laboratory examination of tumour tissue. Molecular testing of the biopsy guides treatment.

Q: What is the difference between screening and diagnosis? Screening uses low-dose CT to look for early lung cancer in people at elevated risk who have no symptoms. Diagnostic testing is done when symptoms develop or a screening result is abnormal. The two serve different purposes.

Q: Is lung cancer treatable? Yes, treatment is available and depends on type, stage, and general health. Options include surgery, radiotherapy, chemotherapy, immunotherapy, targeted therapy, and palliative care. Early-stage disease has much better outcomes than advanced disease.

Q: What is non-small cell lung cancer? Non-small cell lung cancer (NSCLC) is the most common type, accounting for about 85% of cases. It includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Treatment depends on stage and molecular testing.

Q: What does molecular testing mean for lung cancer treatment? Molecular testing analyses the tumour for specific genetic changes — mutations or fusions — that can be matched to targeted drugs. Results determine whether targeted therapy, immunotherapy, or chemotherapy is most appropriate.