CYP19A1 and endometrial carcinoma: Patients receiving combination therapy exhibited the best disease-free survival.19 Letrozole is a third-generation aromatase inhibitor that can reduce estrogen levels by inhibiting estrogen synthesis, leading to a reduction in receptor-mediated growth stimulated in estrogen receptor-positive tumors such as endometrial carcinoma.20 21 The combination of GnRHa and letrozole has been reported to be an option for preserving fertility in women with endometrial carcinoma and atypical endometrial hyperplasia.