Lung Cancer: Types, Diagnosis and Treatment

Lung cancer is the world's most lethal cancer — in both men and women, it causes more deaths than colorectal, breast and prostate cancers combined. Approximately 85% of cases are linked to tobacco smoking, but the disease also affects non-smokers, and its rate in never-smokers is rising.

Types of Lung Cancer

Non-Small Cell Lung Cancer (NSCLC)

Non-small cell lung cancer accounts for approximately 85% of all lung cancers. It grows more slowly than small cell lung cancer and is broadly divided into three subtypes:

• Adenocarcinoma — the most common subtype; frequently found in the outer lung regions; most common type in non-smokers and women
• Squamous cell carcinoma — arises from the cells lining the airways; often located centrally near the main bronchi
• Large cell carcinoma — a diverse group of tumours that do not show features of adenocarcinoma or squamous cell type on biopsy

Despite slower growth, 40% of NSCLC patients have disease that has spread beyond the chest at the time of diagnosis.

Small Cell Lung Cancer (SCLC)

Small cell lung cancer accounts for approximately 15% of lung cancers. It is highly aggressive, divides rapidly, and typically has spread to other parts of the body before symptoms appear. SCLC is strongly associated with heavy smoking.

Causes and Risk Factors

• Smoking — responsible for approximately 85% of cases; risk is dose-dependent (pack-years). Former smokers remain at elevated risk for decades after quitting.
• Passive smoke exposure — second-hand smoke raises risk by 20–30%
• Radon gas — a naturally occurring radioactive gas that accumulates in buildings; the second-largest cause of lung cancer in non-smokers
• Occupational exposures — asbestos, arsenic, chromates, nickel, chloromethyl ethers, polycyclic aromatic hydrocarbons, and coke oven emissions
• Air pollution — particularly fine particulate matter (PM2.5)
• Lung scarring — tuberculosis-related lung damage may predispose to adenocarcinoma
• Genetic factors — a family history of lung cancer confers modest additional risk independent of smoking

Approximately 15–20% of lung cancers occur in people who have never smoked.

Symptoms

Lung cancer often causes no symptoms in its early stages. When symptoms occur, they vary with the tumour's size, location, and pattern of spread.

Pulmonary symptoms:

• Persistent or worsening cough — the most common symptom, especially in smokers whose chronic cough changes character
• Coughing up blood (haemoptysis) — any amount warrants urgent investigation
• Breathlessness or wheezing — from airway obstruction
• Recurrent chest infections or pneumonia that fails to resolve

General symptoms:

• Unintentional weight loss
• Loss of appetite
• Fatigue and weakness
• Chest pain, especially if the tumour invades the chest wall

Symptoms of spread:

• Headache, confusion or seizures — brain metastases
• Bone pain — skeletal metastases
• Jaundice — liver involvement
• Swollen lymph nodes in the neck

Specific syndromes:

• Horner's syndrome — drooping eyelid, small pupil, reduced sweating on one side of the face, caused by tumour compressing neck nerves
• Superior vena cava (SVC) syndrome — swelling of the face, neck and arms from obstruction of the major vein draining the upper body
• Pancoast tumour — shoulder and arm pain from apical tumour pressing on the brachial plexus

Diagnosis

Imaging

Chest X-ray is typically the first investigation, detecting most lung tumours — though small nodules may be missed.

CT scan of the chest provides detailed cross-sectional images, identifying smaller lesions, enlarged lymph nodes, and involvement of surrounding structures. CT guides decisions about which sampling technique to use.

PET-CT scan combines metabolic imaging (PET) with anatomical imaging (CT) to detect active tumour deposits throughout the body. It is the standard for staging — identifying lymph node involvement and distant metastases — and avoids unnecessary surgery in patients with widespread disease.

MRI of the brain is performed to detect cerebral metastases in patients being considered for curative treatment.

Low-dose CT (LDCT) screening — in high-risk individuals (age 50–80, ≥20 pack-year smoking history), annual LDCT screening reduces lung cancer mortality by approximately 20%. This is now recommended in multiple countries.

Tissue Diagnosis

A tissue sample (biopsy) is essential to confirm the diagnosis and guide treatment.

• Bronchoscopy — a flexible scope passed through the airway to biopsy accessible tumours; endobronchial ultrasound (EBUS) extends reach to mediastinal lymph nodes
• CT-guided percutaneous needle biopsy — for peripheral tumours not reachable by bronchoscope
• Thoracoscopy (VATS) — minimally invasive surgical sampling for tumours not accessible by other means
• Pleural fluid analysis — if a pleural effusion is present, fluid analysis can confirm malignancy

Molecular and Genetic Testing

All patients with NSCLC (particularly adenocarcinoma) require comprehensive molecular profiling of the tumour to identify actionable mutations:

Gene/Target	Prevalence in NSCLC	Available Treatment
EGFR mutation	15–30% (higher in Asians)	EGFR inhibitors (osimertinib, gefitinib)
ALK rearrangement	3–5%	ALK inhibitors (alectinib, lorlatinib)
ROS1 rearrangement	1–2%	ROS1 inhibitors (crizotinib, entrectinib)
KRAS G12C	13%	KRAS inhibitors (sotorasib, adagrasib)
BRAF V600E	1–2%	BRAF/MEK inhibitors
PD-L1 expression	Variable	Checkpoint immunotherapy eligibility

Staging

The TNM staging system classifies lung cancer based on:

• T — tumour size and local invasion
• N — lymph node involvement
• M — distant metastasis

Stage	Description	5-Year Survival (NSCLC)
I	Localised to the lung	60–90%
II	Limited nodal involvement	30–60%
III	Extensive nodal disease, locally advanced	10–35%
IV	Distant metastases	<10% (improving with targeted therapy)

Treatment

Surgery

Surgery offers the best chance of cure in early-stage NSCLC (stages I–II and selected stage III).

• Lobectomy — removal of an entire lobe; the standard curative operation
• Video-assisted thoracoscopic surgery (VATS) — minimally invasive approach with smaller incisions, less pain and faster recovery
• Pneumonectomy — removal of an entire lung; reserved for centrally located tumours
• Sublobar resection (segmentectomy or wedge) — for small peripheral tumours in patients with limited lung reserve

SCLC is rarely treated surgically due to its disseminated nature at diagnosis.

Radiation Therapy

• Stereotactic ablative radiotherapy (SABR/SBRT) — high-dose, precisely targeted radiation for small tumours; an alternative to surgery in patients unfit for operation; cure rates approaching surgery in early-stage disease
• Conventional radiotherapy — combined with chemotherapy (chemoradiation) in locally advanced stage III NSCLC
• Prophylactic cranial irradiation (PCI) — used in SCLC to reduce the risk of brain metastases

Chemotherapy

• First-line platinum-based combinations (cisplatin or carboplatin + pemetrexed or paclitaxel) in NSCLC without actionable mutations
• First-line chemotherapy for SCLC: cisplatin or carboplatin + etoposide, often combined with immunotherapy
• Chemotherapy is also used as adjuvant therapy after surgery in higher-risk early-stage disease

Targeted Therapy

For patients with actionable molecular alterations, targeted drugs dramatically outperform chemotherapy:

• EGFR inhibitors (osimertinib preferred) — median progression-free survival >18 months in EGFR-mutant NSCLC
• ALK inhibitors (alectinib, lorlatinib) — highly effective; may provide years of disease control
• KRAS G12C inhibitors — recently approved; first effective treatment for a previously undruggable target

Immunotherapy

Checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab) block tumour evasion of the immune system. They are used:

• As first-line monotherapy in NSCLC with high PD-L1 expression (≥50%)
• Combined with chemotherapy in other NSCLC subtypes
• Combined with chemotherapy in SCLC

Long-term responses to immunotherapy are seen in a subset of patients — some remain in remission for 5+ years.

Lung Cancer Care in China

China's top-tier oncology institutions deliver internationally competitive oncology services:

• Diagnosis pathway: PET-CT, EBUS bronchoscopy, CT-guided biopsy and comprehensive molecular profiling
• Full genomic profiling: next-generation sequencing panels covering all actionable NSCLC targets, including EGFR, ALK, ROS1, KRAS, MET, BRAF, RET and NTRK
• VATS surgery: minimally invasive lobectomy performed routinely; experienced centres achieve excellent outcomes
• SABR: stereotactic radiotherapy available with sub-centimetre targeting precision
• Targeted therapy access: EGFR, ALK, and other targeted agents are available — important for patients requiring long-term maintenance treatment
• Second opinion consultations: rapid multidisciplinary review of imaging and pathology for patients diagnosed elsewhere

Contact a ChinaMedicalTour care navigator to arrange a lung cancer assessment or treatment consultation.

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Medical content based on MSD Manuals, authored by Robert L. Keith MD (University of Colorado School of Medicine), reviewed by Richard K. Albert MD. Last reviewed May 2023, updated April 2025.

Frequently Asked Questions

What diagnostic materials are needed for remote lung cancer pre-consultation in China?

High-resolution chest CT scans, PET-CT imaging, biopsy pathology reports, and molecular genetic testing results (such as EGFR, ALK, ROS1, and PD-L1) are submitted for multidisciplinary thoracic oncology review.

What advanced treatment modalities are evaluated for lung cancer?

Chinese thoracic oncology centers evaluate uniportal video-assisted thoracoscopic surgery (VATS), robotic lobectomy, targeted kinase inhibitors, immune checkpoint inhibitors, and stereotactic body radiation therapy (SBRT).

Can international patients continue systemic targeted therapy after returning home?

The treating hospital issues a bilingual discharge summary detailing medication dosage, cycle timing, and monitoring parameters so domestic oncologists can coordinate ongoing care safely.