Has anyone had diarrhea with radiation?

Has anyone in the Forum had RT to their lymph node basin only and then experienced diarrhea during treatment? How did you handle it?

I’ve just completed my 15th VMAT IMRT treatment to my lymph node basin only. I started experiencing diarrhea two days after the 14th treatment and hours after the 15th treatment. My oncologist doesn’t believe that it’s connected to the radiation because he’s avoiding the bowel and previously treated prostate bed.