Prostate cancer side effects not paid off

I havé béen treating for cancér , The cancer séems to be ok and in recession now My problem is I suffering from side effects as éxhaustion, memory and poor concentration It's been 4 years now and time to be declared permaneneñt,whitch they don't want to continué às they say it's nor cancer, my problem is théy been paying this ,but don't wanna pay out ñow because it is 4 yeárs and the original claim cancer is currently in reçession