Long-term therapy with dienogest or other oral cyclic estrogen-progestogen can reduce the need for ovarian endometrioma surgery.

Decreased mean largest ovarian endometriomas'diameter after 12 months and reduction of the need for surgical treatment by 30% were observed in dienogest and estrogen-progestogens groups. Long-term treatment with dienogest had a greater effect in alleviating dysmenorrhea and pain.