It's hard to say without knowing more but at Stage 3 you sometimes aren't offered the operation and Radiotherapy is offered to treat a wider area.
There is often debate about the best treatment for each case. Usually a Multi Disciplinary Team discuss your case to allow both the surgeon and the oncologist to have their say.
Assuming that's happened and you're having the operation there is plenty of reading matter on here. Some people have done write ups about their operations. I have. If you read my profile and if you also click on the link to the separate website I did. There is a page about the operation and a page about the post operation.
I was wondering if you'e a private patient having a CT scan. Most just have an MRI during diagnosis.
Everybody has different cases, different factors during the operation. Although there is a pattern. I thought the operation was fairly easy as long as you take it easy yourself afterwards for a while.