@hhsn12211 Each case is different; also doctors have varying approaches. Some cases require the tumor to be shrunk through chemo and/or radiotherapy before surgery. Other cases can be managed by surgery first and a wait-and-see attitude afterwards or chemo and/or radiotherapy after.
If there is a way you could get a second opinion, I would encourage you to do it. Always ask the doctors why they suggest such or such treatment.

This site (https://fightcolorectalcancer.org/facing-colorectal-cancer/) is very helpful.

Have a look at the various forums here that revolve around rectal cancer, like this one: https://connect.mayoclinic.org/discussion/rectal-cancer-diagnosis-very-low-in-the-rectum/