Oh my, I didn't realize you just bailed on a surgery yesterday. How stressful! I don't know any of the details of your case, and I'm not a doctor, so my advice is based on my own experience and research, as well as family experience.

Have the surgery. Get that cancer out of your body.

Are you being scheduled for a robotic-assisted laparoscopic surgery? As far as I know, it's uncommon for them to do a transfusion during that. I think they had me sign a form giving them permission to give me blood if necessary, but they didn't do it.

Reasons:
1) Surgery is the recommended first treatment for endometrial cancer in virtually all cases. It is quite successful, and for low grade cancers that haven't invaded very far into the uterus, often no other treatment is necessary. Surgery has been the main treatment for a long time. My grandmother's sister had a hysterectomy + ovary removal for endometrial cancer 80 years ago. (She was in her 20s at the time, and lived another 60 years of a full, interesting life, with a happy marriage.)

As far as I can tell, the only times they don't do surgery first are if the patient is so unhealthy that they can't handle the surgery, or if the patient chooses not to. Possibly also if the cancer has already spread widely. In these cases, they may do radiation therapy, but since so few women have radiation without having a hysterectomy first, it's hard to know how well it works.

2) If I were choosing between the experiences of having the laparoscopic surgery and having pelvic radiation therapy, I'd pick the surgery. (I had a robotic-assisted total hysterectomy + bilateral salpingo-oophorectomy in August. I have not had pelvic radiation therapy, so I'm not speaking about that from personal experience. I have only read about it.) The surgery is fast; you're asleep while it happens; and in a week or so, you can mostly go about your business. Pelvic radiation involves going to the hospital most every day for several weeks, and leaves you reaching for the Imodium. Some people have worse side effects that last after the treatment is over.

If you're having an abdominal hysterectomy, the recovery takes longer, so the experience might be more comparable to the radiation. But I still think you should have it done for the first reason.