Why is lung cancer so deadly?

Lung cancer kills more people than any other cancer — 2.21 million in 2020 — because most cases are diagnosed at advanced stage (III or IV), when curative surgery is no longer possible. At stage IV, 5-year survival is approximately 7%. This is partly because early-stage lung cancer is asymptomatic: cough, breathlessness and haemoptysis only appear when the tumour is large or has spread. By contrast, localised-stage 5-year survival exceeds 60%.

What causes lung cancer?

Tobacco smoking causes approximately 85% of lung cancer — with risk proportional to pack-years smoked and substantially reduced (but not eliminated) after cessation. Other causes: passive smoking; radon gas (second leading cause — 3-14% of cases); asbestos and silica (occupational); air pollution (outdoor PM2.5 and indoor household combustion); and arsenic in drinking water. EGFR-mutant adenocarcinoma in never-smokers is increasingly recognised, particularly in East Asian women, suggesting additional environmental or genetic drivers.

What are the warning signs?

Persistent cough (worsening or blood-stained); breathlessness; chest pain; weight loss; loss of appetite; repeated chest infections; hoarseness; difficulty swallowing; and superior vena cava obstruction (facial swelling, arm oedema). Many lung cancers produce no symptoms until advanced. High-risk individuals (heavy smokers, occupational exposures) should discuss LDCT screening eligibility with their physician.

How is lung cancer treated?

Treatment depends on type, stage and molecular profile. Early-stage NSCLC: surgical resection (lobectomy) with curative intent; stereotactic body radiotherapy (SBRT) for inoperable early-stage. Advanced NSCLC: immunotherapy (pembrolizumab alone or with chemotherapy for PD-L1 high tumours); targeted therapy (osimertinib for EGFR; alectinib for ALK; sotorasib for KRAS G12C). SCLC: platinum-based chemotherapy plus immunotherapy. Concurrent chemoradiation for locally advanced unresectable disease. Palliative care throughout.

What is LDCT screening?

Low-dose CT (LDCT) screening — annual CT scan for high-risk individuals (typically aged 50-80 with 20+ pack-year smoking history) — detects lung cancer at an earlier, more treatable stage. The NLST trial showed 20% mortality reduction; the NELSON trial showed 24%. WHO now recommends LDCT in its cancer screening guidelines for eligible individuals in settings with adequate follow-up capacity. Major barriers: cost, CT availability, high false-positive rate, and the need for multidisciplinary follow-up.

What is the treatment revolution for NSCLC?

The past decade has transformed advanced NSCLC from a uniformly fatal diagnosis to a chronic disease for many patients. Immune checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab) produce durable responses in patients with high PD-L1 expression or tumour mutational burden. Targeted therapies (EGFR inhibitors, ALK inhibitors, RET inhibitors, KRAS inhibitors) produce remarkable responses in patients with specific molecular alterations. However, resistance develops, and access to molecular testing and these agents is extremely limited in LMICs.

What is adenocarcinoma in never-smokers?

Adenocarcinoma — the most common NSCLC subtype — occurs in never-smokers at higher rates than other lung cancer types, particularly in East Asian women. These tumours have a high prevalence of EGFR, ALK and ROS1 mutations — making them highly responsive to targeted therapy. Their molecular biology is distinctly different from smoking-related lung cancers. Air pollution, second-hand smoke, radon and genetic susceptibility are suspected drivers, though causation is not fully established.

How can lung cancer be prevented?

Tobacco control is the primary prevention strategy — eliminating smoking would prevent approximately 85% of lung cancers. Policies: tobacco taxes; smoke-free environments; plain packaging; advertising bans; cessation support. Secondary prevention: radon home testing and mitigation; occupational exposure controls (asbestos, silica, diesel exhaust, chromium); air pollution reduction. LDCT screening for high-risk individuals is a tertiary prevention strategy for early detection.

How does tobacco control relate to lung cancer prevention?

Countries with sustained, comprehensive tobacco control programmes show declining male lung cancer mortality rates: the US, UK and Australia have achieved 30-40% reductions in lung cancer mortality over 3 decades following tobacco control implementation. Countries with more recently adopted tobacco control (including parts of Eastern Europe and Asia) face the peak of their tobacco-driven lung cancer epidemics now. The WHO MPOWER package provides the evidence-based tobacco control framework.

What is the lung cancer burden in LMICs?

Lung cancer is rapidly increasing in LMICs as tobacco use spreads and populations age. Access to molecular testing (needed for targeted therapy), immunotherapy and LDCT screening is extremely limited. Most LMIC patients receive platinum-based chemotherapy if any treatment at all — with much poorer outcomes than those in high-income countries receiving modern immunotherapy and targeted agents. Expanding access to predictive biomarker testing and novel therapies is a major global equity challenge.

What is radon and should I test my home?

Radon is a naturally occurring radioactive gas produced by uranium decay in soil and rock that accumulates in enclosed spaces — particularly basements and ground floors. It is the second leading cause of lung cancer after smoking. The WHO recommends a reference level of 100 Bq/m3 (some guidelines use 148 Bq/m3). Testing involves placing a passive detector in the home for 3+ months. Mitigation (sub-slab depressurisation) reduces radon to safe levels. Combined with smoking, radon risk is multiplicative.

How does GMJ News cover lung cancer?

GMJ News tracks GLOBOCAN lung cancer data, immunotherapy and targeted therapy trial results, LDCT screening policy expansion, tobacco control as the primary prevention strategy and LMIC treatment access. Lung cancer is a major concern in Georgia — given historically high male smoking rates. PHIG's tobacco control advocacy and the Georgian Medical Journal's oncology coverage make this a direct editorial priority.

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Lung Cancer

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Lung cancer is the world's deadliest cancer — 2.21 million deaths in 2020 — killing more people than colorectal, breast and prostate cancers combined, and accounting for 18% of all cancer deaths (IARC GLOBOCAN 2020). Tobacco causes approximately 85% of cases, making lung cancer the most preventable major cancer — yet the diagnosis-to-death gap and the revolution in treatment (immunotherapy, targeted therapy for EGFR/ALK mutations) have fundamentally changed the outlook for many patients. Globally, lung cancer disproportionately affects low- and middle-income countries where tobacco control is weakest and treatment access is most limited.

Key messages

Most deadly cancer

Lung cancer killed 2.21 million people in 2020 — more than colorectal, breast and prostate cancers combined — and accounts for 18% of all cancer deaths globally (IARC GLOBOCAN 2020).

85% from tobacco

Approximately 85% of lung cancers are caused by tobacco smoking, making lung cancer the most preventable major cancer. Passive smoking causes approximately 25% of cases in never-smokers.

Treatment revolution

Immunotherapy (checkpoint inhibitors) and targeted therapies (EGFR, ALK, ROS1, KRAS inhibitors) have transformed treatment for eligible patients — extending survival from months to years. However, these advances are largely inaccessible in LMICs.

Low survival — late diagnosis

Five-year survival for lung cancer is approximately 19% in high-income countries — because most cases are diagnosed at advanced stage. When diagnosed at localised stage, 5-year survival exceeds 60%.

CT screening works

Annual low-dose CT (LDCT) screening of high-risk individuals (heavy smokers aged 50-80) reduces lung cancer mortality by 20% (NLST) to 24% (NELSON trial). Recommended in the US and increasingly in Europe, but rarely available in LMICs.

Rising in never-smokers

Lung cancer in never-smokers — particularly adenocarcinoma driven by EGFR mutations — is increasing globally, especially in East Asian women. Air pollution, radon, asbestos and genetic predisposition are contributors.

Key statistics

2.21M

lung cancer deaths/year (2020)

IARC GLOBOCAN

2.09M

new lung cancer cases/year (2020)

IARC GLOBOCAN

18%

of all cancer deaths

IARC

85%

caused by tobacco smoking

WHO

19%

5-year survival (all stages combined)

SEER/GLOBOCAN

20-24%

mortality reduction with LDCT screening

NLST/NELSON

Top 5 cancer killers globally (deaths, thousands) — IARC GLOBOCAN 2020

Source: IARC GLOBOCAN 2020. Lung cancer leads by a large margin in cancer mortality.

Glossary of key terms

Non-small cell lung cancer (NSCLC)
WHO/IASLCThe most common lung cancer type (85% of cases) — comprising adenocarcinoma, squamous cell carcinoma and large cell carcinoma. Treated with surgery (early stage), chemoradiation, immunotherapy and targeted therapy depending on molecular profile.

Small cell lung cancer (SCLC)
WHO/IASLCA highly aggressive neuroendocrine tumour accounting for ~15% of lung cancers — almost exclusively in heavy smokers. Responds initially to chemotherapy but has very high relapse rates. Immunotherapy (atezolizumab) now added to first-line chemotherapy.

EGFR mutation
ESMO/ASCOEpidermal Growth Factor Receptor mutations — present in approximately 15% of Western and 40-50% of East Asian NSCLC adenocarcinomas. Targeted by EGFR tyrosine kinase inhibitors (erlotinib, gefitinib, osimertinib) that dramatically prolong survival in eligible patients.

PD-L1 / immunotherapy
FDA/EMAProgrammed death-ligand 1 (PD-L1) expression predicts response to immune checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab). High PD-L1 expression (>50%) identifies patients most likely to benefit from immunotherapy — now first-line treatment for many advanced NSCLC patients.

LDCT screening
NLST/NELSONLow-dose computed tomography annual screening of high-risk individuals (heavy smokers aged 50-80) reduces lung cancer mortality by 20-24%. Recommended by multiple guidelines; uptake remains low even in high-income countries with established programmes.

Radon
IARC/WHOA naturally occurring radioactive gas from uranium decay in soil and rock — the second leading cause of lung cancer after smoking, responsible for approximately 3-14% of all lung cancer deaths. Risk is highest in smokers in high-radon homes. Home radon testing and mitigation are preventive.