Yes uterine cancer can cause death if not treated in time and allowed to spread too far.
Without treatment the uterine cancer can spread to far and then once the uterine cancer gets too far spread then it becomes impossible to treat and get rid of the uterine cancer.
When the uterine cancer does get too far spread then you can die within 2 to 5 years of getting the uterine cancer.
So it's good to get tested to catch anything such as cancer and uterine cancer so that the uterine cancer and other cancer can be treated and cured before it spreads too far.
Even with treatment some people may still die of the cancer but your chance of surviving is much higher if you do get treatment for the uterine cancer.