I often see pilots and cabin crew as patients for skin cancer treatment, and have suspected that the increased UV and cosmic radiation exposure at altitude with every flight might be a contributing factor. A recent analysis published by the British Journal of Dermatology confirms these suspicions. It seems that pilots and cabin crew have approximately double the risk of melanoma and keratocytic skin cancer (basal cell and squamous cell cancer) compared with the general population. While some of this risk may be theorized to be related to lay over days spent on the beach at exotic destinations, the magnitude of the increased risk implies that the repeated long hours at altitude is a significant factor. Flight crew, even more than the average person need to be especially vigilant in checking their own skin and see their dermatologist routinely for skin cancer screening.

Citation:

Do airline pilots and cabin crew have raised risks of melanoma and other skin cancers? Systematic review and meta‐analysis.
K. Miura C.M. Olsen S. Rea J. Marsden A.C. Green
First published British Journal of Dermatology: 26 December 2018 https://doi.org/10.1111/bjd. 17586