Cancer incidence in airline cabin crew.

R ecent reports highlighting increased cancer incidence and mortality among airline pilots and cabin crew have raised concerns about potential exposure of these workers to known or suspected carcinogens, in particular cosmic ionising radiation. Higher radiation dose rates are found at higher altitudes and in the polar regions, and mean doses to flight crew have been increasing over time as longer flights at higher altitudes have become more frequent. Other possible hazards that may play a role in cancer risk for flight crew include irregular working hours and disturbances of circadian rhythm. Epidemiological studies of mortality and cancer incidence in flight crew have been reviewed recently, 2 but in the past 2–3 years, 10 new studies of pilots or cabin crew have been published, the majority of which result from a combined effort underway by the European Community. These studies include three mortality studies and seven cancer incidence studies. Overall, the reports suggest that pilots are at increased risk of malignant melanoma, non-melanoma skin cancer, and possibly acute myeloid leukemia, and that cabin crew are at increased risk for breast cancer and malignant melanoma. However, the question remains as to whether the observed excesses are due to occupational exposures or nonoccupational factors, such as reproductive history and lifestyle. Studies of cabin crew have been limited by exposure assessment that is based on data readily available from employment records such as duration of employment, domestic or international status, or employment before or after the operation of jet aircraft. In contrast, most recent studies of pilots have estimated radiation dose from cumulative aircraft-specific block hours. Most of the studies have taken advantage of existing national record systems for cancer information, but are limited in their ability to take into account the well established non-occupational risk factors for the cancers of interest. Yet despite these limitations, the studies are remarkably consistent in providing evidence of increased risk for these cancers.