Kindly keep your top boss (appellate authority) informed of the discrimination with a request to address it. Or
if you have a Union in your Union kindly take their help or
Approach the local MLA or MP or any other political people to help you or
Present your case to your next boss, when he is alone or in his house, in such a way that he is convinced of the discrimination and get his sympathy or
Consult an advocate dealing with labour tribunal and/ or administrative tribunal. cases, to consider your handicap (cancer) and get the benefits that may be available to handicaped persons.
Pls allow me to be devil's advocate here. while I like your username, I find the usage 'victim' of cancer slightly problematic. You should look at yourself more like a survivor than a victim.
Coming to your problem, there are many people, less fortunate who expect equal treatment at workplace; despite having some issues while performing the task. I don't claim to understand your pains and what toll this disease has taken on your health, but if you could do your work to the best of your abilities, perhaps someone might relent and let you off the hook. The unfortunate truth is that many times, employees are not looked at as humans but just work machines. The best way would be to hang on, do your work, talk to colleagues and superiors and hope that things will get better.
Myself also gone such kind of situation but I consulted only GOD who whispered thru my inner voice. that inner voice conveyed me to be sincere in your duties whatever you can do within office timings just continue without any fear. Definately I felt lonely and alone but this isolation brought me a deep silence and a unique peace of mind which I could not experience if i am not tortured by my office colleagues or seniors. This could happened only with the grace of GOD who gave me the divine strength, self confidence and ultimate will power. By looking this uniqueness in me, all people torturing me went back and started their own job. Today no body is disturbing me and i am living a happy and peaceful life which could have been possible just by BLESSINGS AND GRACE OF GOD. You should call your GOD with bottom of your soul and heart, he will give you the answer and strength thru your inner voice.