From everything I have read, I too believe sugar can be like a steroid to Cancer.
I found this info.... maybe this can help?
https://www.independent.co.uk/news/health/breast-cancer-cure-tcell-immunotherapy-tumour-treatment-disease-world-first-a8382806.html

ps, this is probably not conventional so the doctors here might not even know about it. Also, from what I understand, radiation and chemo are both bad and sometimes exacerbates the cancer.