Pills AND an IUD as treatment for Endometriosis?

Hi, I had a meeting with my gyno who said he is fairly sure I have endometriosis and he wants to treat it. I have a Mirena and have for 2 years. He wants to put me on birth control pills along with my IUD to help stop my cycle completely with hormone surpression. Is this normal? Does this help? I can't find much about it online and now I'm worried. Is this good/safe to do without the laproscopic surgery?