Bowel Resection With Giant Cyst - Cancer?

Again, haven't been on in ages. Seems I always have an issue, though, every year or so.

This time a large "cyst" was found when I went to the ER for severe "gas" pain back Labor-Day weekend, with CAT scan.

Now I have a young surgeon who has looked at that and blood tests (CgA - high) and MRI and says I need to have all my right colon removed along with the cyst. Just in case it's cancer, basically.

Anyone have a huge cyst outside their bowels and have this kind of surgery? I am scared of cancer, but even if I don't have that I'm scared of what the complications might be from the surgery itself and removing 1/3 of my colon. I'm 44, have a very young son, and a mother already bereaved from losing my sister last year to breast cancer. I start worrying about sepsis, MRSA and "leakage" (poor surgical connections) and blockage. Is it silly to worry about all this?

What bugs me is that the surgeon seems very concerned about cancer, although the 1 marker - CgA - that was high could be high because of my 7-year usage of double Nexium. I also had a "beautiful" colonoscopy the month before the ER visit.