Complex sentence: Women with Lynch syndrome have a 40-60% risk of developing endometrial cancer, higher than their risk of developing colorectal cancer or ovarian cancer; ovarian cancer and endometrial cancer develop simultaneously 20% of the time in Lynch syndrome.
Split into simpler sentences: Women with Lynch syndrome have a 40--60% risk of developing endometrial cancer, higher than their risk of developing colorectal cancer or ovarian cancer. Ovarian cancer and endometrial cancer develop simultaneously 20% of the time in Lynch syndrome.