Hi, I have always thought that unless your consultant says that there is a problem with any side effects from treatments that may impair your driving, that you don’t need to declare to anyone that you have cancer. I have chemo induced peripheral neuropathy and that is on the list of medical conditions you have to declare to the DVLA and on car insurance. It hasn’t been a problem, I had to fill in the DVLA forms and send my licence back and they sent me one back which only lasts for 5 years. When I told my car insurers this they said it wouldn’t affect my premium and there was nothing extra to pay, but I do have to declare I have a limited licence when renewing. Hope this helps.