My cancer was located between the internal and external sphincters and was the size of a walnut. My surgeon told me I would have a colostomy. I told him NO! I did not want one. After the surgery He placed a ileostomy for a while (about a year) to let the surgery heal.
Before the surgery I had about 3 months of chemo and radiation. The surgeon removed all of the internal sphincter and about half of the external. The surgeon and I had several sometimes kind of heated talks about a colostomy. I still choose not to have a bag. Long story short, I do not have a bag today. It has been a challenging at times, but I have learned to have sort of normal life.
If you do decide to have the surgery, get your self a bidet. It has been a life saver for me, you can get a pretty nice one on amazon for about $500. You can get cheaper ones but you get what you pay for, ( I have bought 6 in the last 8 years) I recommend a TOTO brand with the continuous warm water. I get diarrhea at times and get constipated also, and the stream of warm water helps with that a lot. ( I sound like a rep for bidets but Im not) I also have a portable bidet in my go bag (with all my supplies I need) for when Im away from home.
As for surgery, I wanted the cancer OUT! I wanted it cut out, nuked out, I didnt care, I just wanted it out. And I didnt want a bag. But it is your choice, and your choice alone. you have to live with your decision. Know your options and just because the surgeon tells you the way they always do the treatment plan, it doesn't mean you have to do it that way. Tell the surgeon what you want. And ALWAYS remember all these doctors work for you, and you can fire them at anytime if they dont want to do what you want done.