Final answer:
The lifetime risk of an ovarian mass being malignant is estimated to be around 5-10%. Pre-menopausal women have a lower incidence of ovarian cancer compared to postmenopausal women. The incidence of ovarian cancer starts to increase significantly after the age of 50.
Step-by-step explanation:
Ovarian masses can either be benign or malignant. The lifetime risk of an ovarian mass being malignant (cancerous) is estimated to be around 5-10%. However, this risk can vary depending on factors such as age, family history, and the type of mass. Pre-menopausal women have a lower incidence of ovarian cancer compared to postmenopausal women. The incidence of ovarian cancer starts to increase significantly after the age of 50.