At 30,000 feet: What pilots and cabin crew should know about cancer risk

Commercial flights often reach altitudes above 30,000 feet, where the thinner air offers less protection from cosmic radiation emitted from space. While most passengers face minimal individual risk from exposure during a single flight, pilots and cabin crew who spend long periods airborne over many years may experience cumulative radiation exposure.

A recent study published in JAMA Internal Medicine revealed that pilots and flight attendants suffer a disproportionate number of radiation-associated cancer deaths compared to the overall workforce. Six-point-nine percent of flight attendants and six-point-seven percent of pilots died from radiation-related cancers, versus five percent of workers in other occupations.

However, the research establishes an association rather than causal proof, suggesting that other occupational factors, such as altered sleep patterns and circadian disruptions, may also factor into cancer risk. Dr Amit Upadhyay, a hematologist and oncologist, explained that the atmosphere thins at cruising altitude, reducing its ability to shield against ionising radiation from space.

Despite each flight's low radiation dose, repeated exposure over a lengthy career could potentially contribute to DNA damage and cancer development. The cancers most closely studied include leukaemia, lymphoma, multiple myeloma, melanoma, breast, thyroid, and central nervous system malignancies. While cosmic radiation is a major concern, the National Academies' 2026 report stresses that sleep disturbances and circadian rhythm disruptions may also play a role.

Dr Upadhyay cautioned that the study does not definitively prove that cosmic radiation alone caused the increased cancer rates among aircrew. Factors like time zone changes and night work could contribute to the risk as well. For regular flyers, the exposure risks are significantly lower compared to those who spend decades working on aircraft.

A frequent flier might encounter around 0.4 mSv of cosmic radiation annually, whereas crew members face approximately 3–6 mSv, depending on flight routes and altitudes. Experts agree that airlines and regulators should monitor and limit cumulative radiation exposure, particularly for those on long-haul, high-latitude, or polar routes.

Possible mitigation strategies include adjusting operational routes and implementing regular medical screenings, including age-, sex-, and risk-appropriate cancer checks.