How Long Should Vitamin C Supplements Be Injected To Veins Of An Elderly Person?

Hi, I had cancer 5 years ago. I did not have cemo or radition. I take vitamin c in my veins. My question is how long will I have to take this? I had breast surgery. It was removed. The left breast. I was 79 years old. I am now 84. Do you have an answer for me? My email is YYYY@YYYY . Thanks doctor. I will wait for your answer. Vivian