That's one of the dirty little 'secrets' that the FEDs and the airlines have been hiding for at least a decade + ... that a disproportionate number of (especially international) airline flight crews -- cockpit and cabin -- have been contracting and dying of cancers of various kinds -- all out of proportion to their number(s) in the general population. The Feds & airlines want it 'kept quiet' because of the astronomical potential liability. I've had many of my former flying mates die or contract cancer ... by their middle '60s.
Remember ... the long-haul jet stuff at altitude just started @ 45 +/- years ago with any great numbers of crew members involved ...
That's why I'm glad I don't fly greater than about 500 feet!
In all seriousness, that's pretty shitty. You would think they would try to shield the cockpits/canopies.