If a uterine polyp seems to be shrinking or disappears completely. should i still have a endometrial biopsy? are women with history of uterine polyps at higher risk of uterine cancer in their lifetime?

You seem to be afraid of getting endometrial biopsy; it is not as bad as you think and the anxiety is much more than the event. There is no way you would know that the polyp is the only thing causing your symptoms though you did not talk about why the uterine polyp was discovered and how you know it shrunk. It is important to evaluate your current symptoms; and cancer risk could be unpredictable.