Hard to say yes or no as it depends very much on a person.
Some stay with immune system still battling cancer
after 9 years and numerous chemo treatments.
In general chemo is significantly harmful for body defense mechanisms and the less one got subjected to the better.
What makes matters worse, cancer is very specific in dealing with someone's energy:
--- in general making it it's own
--- this means, if to return this energy to body, one gets
nearly as healthy as was before, unlike diseases which deplete energy in general and this energy is unrecoverable.
Cancer at last stages also forms energy holes but the energy taken is still in tumour.
Chemotherapy if not succeded, depletes a good deal of energy so one has to generate it again.
As more and more energy gets in tumour this means less chances to win.