Does smoking increase the risk for lung cancer more than vaping?

Smoking vs Vaping: Lung Cancer Risk

Smoking tobacco dramatically increases lung cancer risk approximately 20-fold compared to non-smokers, while the evidence for vaping's independent cancer risk remains insufficient—however, combining vaping with smoking appears to quadruple the already elevated cancer risk from smoking alone. 1, 2

Established Risk from Cigarette Smoking

Tobacco smoking is the single most important causal determinant of lung cancer, responsible for approximately 85% of all lung cancer cases and 85-90% of lung cancer-related deaths. 1, 3, 4

Quantified Risk Magnitude

• The relative risk for lung cancer is approximately 20-fold higher for smokers compared to non-smokers. 1, 4
• Tobacco smoke contains more than 50 known carcinogens. 1, 4
• A clear dose-response relationship exists: risk increases with both the number of cigarettes smoked per day and the total years of smoking (pack-years). 1
• There is no risk-free level of tobacco exposure. 1, 4

Cancer Types Associated with Smoking

• Smoking causes 90% of male and 79% of female lung cancers. 5
• The American Society of Clinical Oncology notes that squamous cell carcinoma is strongly associated with smoking exposure. 3
• Beyond lung cancer, smoking increases risk for kidney, bladder, pancreatic, gastric, cervical cancer, and acute myeloid leukemia. 1, 4

Current Evidence on Vaping and Lung Cancer Risk

The impact of vaping on lung cancer risk has not been established in clinical outcomes data, though concerning mechanistic and early observational evidence exists. 1

Key Guideline Statement

The Annals of Oncology (2020) explicitly states: "Whether completely switching from tobacco cigarette smoking to vaping of an e-cigarette improves the outcome of lung cancer patients treated with chemoradiotherapy has not been established." 1

Emerging Research Concerns

A 2024 case-control study from central Ohio found that individuals who vaped in combination with chronic smoking had a fourfold higher lung cancer risk (OR=38.7) compared to those who only smoked cigarettes (OR=9.6), after adjusting for comorbidities. 2

• This finding was consistent across both men and women and for the main histological cell types of lung cancer. 2
• The unadjusted odds ratio for combined vaping and smoking was even higher (OR=58.9 vs OR=13.9 for smoking alone). 2

Biological Plausibility for Vaping Risk

E-cigarette devices and vaping fluids contain both definite and probable carcinogens: 6

• Nicotine derivatives (nitrosnornicotine, nitrosamine ketone)
• Polycyclic aromatic hydrocarbons
• Heavy metals including organometal compounds
• Aldehydes and complex organic compounds (many used as flavorings)
• Formaldehyde formed from pyrolysis of glycerol 6

Nicotine vaping may cause cancer in individuals with chronic obstructive pulmonary disease (COPD), as COPD sensitizes the alpha-7 nicotinic receptor, enhancing carcinogenic effects and turning nicotine itself into a carcinogen. 7

Critical Clinical Implications

For Current Smokers

Current smokers should be actively supported to quit smoking entirely, not switch to vaping. 1

• The US Preventive Services Task Force recommends proven behavioral counseling and FDA-approved pharmacotherapy for smoking cessation rather than e-cigarettes. 8
• E-cigarettes are not approved as smoking cessation aids by regulatory agencies. 8
• Smoking cessation decreases lung cancer risk, though former smokers maintain elevated risk compared to never-smokers. 1, 4

For Former Smokers Considering Vaping

Individuals with a history of tobacco use should be advised to avoid vaping and e-cigarettes entirely. 8

• Nicotine, regardless of delivery method, is highly addictive and has significant cardiovascular effects. 8
• Vaping products affect both cardiovascular and respiratory systems, contradicting perceptions that e-cigarette use is harmless. 8
• The Forum of International Respiratory Societies recommends that electronic nicotine delivery devices should be restricted or banned until more information about their safety is available. 8

For Patients with Lung Cancer

Continued smoking after lung cancer diagnosis significantly worsens outcomes: 1, 9

• Decreased overall survival 1
• Higher risk of tumor recurrence 1
• Increased risk of second primary tumors 1
• Decreased quality of life 1
• Increased treatment-related toxicity 9

Common Pitfalls to Avoid

Do not underestimate the risk of "light smoking"—even low levels of tobacco exposure significantly increase cancer risk. 4

Do not recommend vaping as a harm reduction strategy, as the long-term cancer risk remains unknown and early evidence suggests it may compound smoking-related risk. 2, 6

Do not assume that switching to vaping eliminates cancer risk in current smokers—the 2024 study suggests the opposite, with combined use showing multiplicative rather than additive risk. 2

Recognize the latency period: Given lag times of approximately 20 years between exposure and cancer development (extrapolating from tobacco data), the full public health impact of vaping may not be apparent for decades. 6