Would a patient who smokes marijuana (cannabis) for 40 years qualify for lung cancer screening with no history of cigarette smoking?

From the Guidelines

A patient who has smoked marijuana for 40 years but has no history of cigarette smoking would not qualify for standard lung cancer screening programs based on current guidelines. The most recent guidelines from the National Comprehensive Cancer Network (NCCN) 1 and the U.S. Preventive Services Task Force (USPSTF) 1 specifically target cigarette smokers with a significant smoking history, and do not include cannabis smoking as a qualifying risk factor. While marijuana smoke does contain carcinogens similar to tobacco smoke, the research on the relationship between marijuana smoking and lung cancer risk is less extensive and conclusive compared to the well-documented link between tobacco smoking and lung cancer.

Some key points to consider in this decision include:

• The NCCN guidelines recommend lung cancer screening with low-dose computed tomography (LDCT) for individuals at high risk for lung cancer, but do not specifically address marijuana smoking as a risk factor 1.
• The USPSTF guidelines recommend annual screening for lung cancer with LDCT for adults aged 50-80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years, but do not include marijuana smoking in their criteria 1.
• Other organizations, such as the American Cancer Society, have issued guidelines that recommend lung cancer screening for individuals at high risk, but also do not specifically address marijuana smoking as a risk factor 1.

Patients with long-term marijuana use should discuss their individual risk factors with their healthcare provider, who may consider other clinical factors when determining if screening would be beneficial on a case-by-case basis. However, based on current guidelines, marijuana smoking alone is not a sufficient reason to qualify for lung cancer screening.

From the Research

Eligibility for Lung Cancer Screening

• The patient in question has a 40-year history of smoking marijuana, but no history of cigarette smoking.
• According to the study 2, heavy cannabis smoking was significantly associated with more than a twofold risk of developing lung cancer over a 40-year follow-up period.
• However, the studies 3, 4, and 5 focus on lung cancer screening for individuals with a history of cigarette smoking, and do not provide direct evidence for marijuana smokers.
• The US Preventive Services Task Force (USPSTF) recommendations for lung cancer screening are based on cigarette smoking history, and do not currently include marijuana smoking as a criterion for eligibility 3.

Lung Cancer Screening Criteria

• The National Lung Screening Trial (NLST) found a reduction in lung cancer mortality with low-dose computed tomography (LDCT) screening in high-risk current and former smokers aged 55 to 74 years 3.
• The Nederlands-Leuvens Longkanker Screenings Onderzoek (NELSON) trial also found a reduction in lung cancer mortality with LDCT screening in high-risk current and former smokers aged 50 to 74 years 3.
• The studies do not provide clear guidance on whether a patient with a 40-year history of marijuana smoking, but no cigarette smoking history, would qualify for lung cancer screening.

Implications for Primary Care Providers

• Primary care providers should be aware of the potential risks and benefits of lung cancer screening for their patients, including those with a history of marijuana smoking 5.
• The study 2 suggests that heavy cannabis smoking may increase the risk of lung cancer, and primary care providers should consider this when assessing their patients' risk factors.
• However, more research is needed to determine the eligibility criteria for lung cancer screening in marijuana smokers, and to inform the risk-benefit calculus of marijuana smoking in medical and public-health settings 2.