I worked through and after. I had some bowel issues but that didn't really interfere with work. The week after I finished radiation, I took the family for a trip to Disneyland, and had no problems or fatigue going all over the park there, except that I visited their bathrooms more often than the average 40-ish visitor.
Some people do report fatigue, and I'm not doubting them--just relating my experience.
When I was getting the treatments, I'd just leave work for 30-40 minutes. The hospital was a few minutes away, with VIP parking for radiation patients right by the door. I'd be in and out the door in less than half an hour most of the time, and back at work in the amount of time some people would take for a morning break.
Dx Feb 2006, PSA 9 @age 43
RRP Apr 2006 - Gleason 3+4, T2c, NX MX, pos margins
PSA 5/06 <0.1, 8/06 0.2, 12/06 0.6, 1/07 0.7.
Salvage radiation (IMRT) Jan-Mar 2007
PSA 9/2007 and thereafter <0.1pcabefore50.blogspot.com