Hi Ann,
Before my surgery, I had a 5FU I.V. pump for the five weeks (while I was getting the radiation) . At that time, I was getting the 5FU 24/7. It got to be too much for me and I started getting pretty bad mouth sores. The Oncologist backed off the dose and I was OK after that. It sounds like your dad got to skip that part. My tumor shrank from the radiation and chemo to the point where the surgeon said he had trouble finding it during the surgery, so I can understand that your dad's tumor might have been staged higher before the radiation.
After my surgery, my six months chemo went something like this (I forget the exact details); One day a week (Fridays) I would go into the chemo ward in the afternoon. I'd be on an I.V. drip for two hours with a continuous drip of the Leucovorin the whole time. At about one hour into the drip, the nurse would "Push" all the 5FU over a period of about a minute. I would get the chemo once a week for six weeks then be off two weeks. This cycle repeated three times for a total of about six months. The chemo caused my hair to thin out a little, but not too much. My fingernails got really thin, to the point where I couldn't open a softdrink can without using a key or something similar to pry up on the ring. My skin got noticeably thinner and the palms of my hands were wrinkled most of the time. I only had one bad bout with diarrhea. The doc lowered my dose of 5FU and again I was ok after that.
I know an older man (he was in his early 60's with colon cancer) who was on the 5FU on a similar treatment pattern for a period of about a year and a half. He had a spot on his liver and the extended chemo was to keep that under control. He tolerated the chemo better than I did and it was just an inconvenience to him.
My wife's uncle was well into his 80's when he was diagnosed with stage four colon cancer. He was on the 5FU the last years of his life in kind of a maintenence program. He also tolerated the chemo very well and continued to play horseshoes every week right up to the end.
It's hard to know if your dad really "needs" the chemo or not. Is he seeing an Ongologist? I've noticed that cancer patients who see an Oncologist tend to get the chemo more often that those who just go see a surgeon. If he is already seeing on Oncologist, a second opinion might be helpful.
Best wishes,
Lou