If I have abnormal bleeding, what are the chances that it's uterine cancer?

Low. Other possibilities are much more likely, such as hormone imbalance, fibroids, polyps etc.
Uterine Cancer. Dysfunctional uterine bleeding (dub) can be due to many things, such as a polyp, infection, or simply a hormonal imbalance. At your age, uterine cancer is extremely unlikely. Your gynecologist will conduct a thorough evaluation to pinpoint the source of the bleeding and recommend appropriate treatment.

Related Questions

Is heavy or abnormal bleeding a sign of uterine cancer? I am 40 years old and have abnormal bleeding. What are my chances that it's uterine cancer? .

It. It would be extremely rare to have uterine cancer. Other possibilities such as hormonal imbalance is a far more common possibility. Fibroids are benign (not cancerous) growths in the uterus that cause bleeding. Checking in with your gynecologist or family practitioner for a complete evaluation is the best decision.

Heavy and long bleeding for 1 year. No pain or mid-cycle bleeding. Reg cycles. Had us today, 5 days into cycle. Endo lining about 8-9cm. Is that abnormal? Could it be uterine cancer?

Probably not, but... Bleeding patterns can change over a woman's life time. Significant changes may mean there is a cause that can be treated like poly, fibroids, or changes in the growth of the uterine lining. Us exams and enodmetrial tissue biopsies can help determine what is the cause and how to treat it. You should see your provider to discuss further.
Cannot say. If you have abnormal bleeding, you shoud see a gynecologist for check up. Ultrasound cannot tell you if you have cancer, but can only guide the doctor to get possible diagnosis.

Do you almost always have bleeding prior to diagnosis of uterine cancer?

Almost. Uterine cancer is usually associated with some bleeding, but there are always exceptions. I trust that you are getting PAP smears done as that can serve as a screening test for uterine cancer as well. If you have not had a PAP smear in more than 3 years, it would be prudent to get one and discuss your issues with your doctor.