Long term effects of radiotherapy

Hi all

I am seeking some information on behalf of my Mum - she has had breast cancer twice, the first about 40 years ago.  She has over the years had several health issues which now seem to have been "diagnosed" as effects from the radiotherapy.  ie ribs breaking from coughing and sneezing, needing a stent put in one of her arteries, diagnosed with asthma which would now appear to be either radiation pheumonitis or fibrosis - she has a really bad cough which has been going on and on and on.

I would be really grateful if anyone could point me in the direction of some information about these kinds of impacts (so far a google search has turned up only very general information) and treatments or management techniques available.

Thank you

Tara