My first round of radiation was from beginning of Oct 2018 to beginning of Nov 2018 for 24 sessions focusing on my pelvic area, back and ribs. At the same time I began Lupron and Zytiga. I felt fatigued and listless until the beginning of January. Then I had 5 more sessions of radiation to address pain in my ribs, right side. I have stage 4 prostate cancer with extensive bone metastasis. I continued to feel better after the radiation was ended. But of course with the Lupron and Zytiga and loss of testosterone, there is loss of muscle mass which affects stamina. But from my experience, it was about a month after radiation was ended that I began to feel a reduction in the fatigue caused by the radiation.