Eeeeh Gods, well I hope this year is much better for you.
I dont know how the cancer treatment would affect your diabetes it depends on the treatment, I had cancer of the thyroid gland and the treatment and everything else, left me pretty tired ahd stressed out, my bg was raised and I needed to increase medication.
Please eat a super healthy diet, no chemicals, additives, no transfats, do a search on Dr Johanna Budwig, contact the Bristol Cancer Help Centre, in fact get info& support from wherever you can but not from those charlatans that scream at you 'if you buy this or that you can cure cancer and whatever, they usually rip you off they send you meds that are not working or some useless paper back book', there are self-help/support groups out there for you and ask your medics for explanations if there is something you dont fully understand.
And dont ever give hope, look at me, I am still here and writing to you.
Thinking of you.
Karen