Hi Sheri. You have`nt said which kind of cancer, but I had radiotherapy every week day for 9 months for prostate cancer. I had no side effects at all, nothing. In fact after each session I went straight back to work. I now have the all clear. Each patient is different. You can suffer loss of appetite, loss of libido, and tiredness, or all three. Good luck, cancer survival rates are improving all the time, and the science is changing almost daily. All the best.