In menopause 2 years had endo biospy 3 mths ago as lining was 6mm. biopsy result nrml now feel dry and spotter a little bright red ! can cancer grow in less than 3 mths?

With a negative endometrial biopsy, it is unlikely that you have uterine Cancer. Yet we can not rule it out if you persist with vaginal bleeding/spotting. Yes cancer can grow in 3 months but it is less likely in your case. Keep a close eye for spotting. If it recurs, seek further guidance from a gynecologist. An Ultrasound of the uterus is the most useful test, to check periodically