I actually flew gliders between chemotherapy infusions and whilst taking oral steroids - in the UK if you're fit to drive a car, you're fit to fly a glider.
The CAA however, whilst very supportive, wouldn't let me fly P1 (powered)until I'd finished with the steroids, I was still taking an oral form of chemotherapy when I returned to power flying and did so for 18 months.
It's a very good (emotional) feeling to get back in an aeroplane (of whatever description) during and after treatment.
My treatment wasn't for cancer (immune system needed blitzing into submission or it would have killed me) but the effects of the treatment were the same.
You can beat it, best of luck.
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