Abstract: Objective To investigate the effects of dydrogesterone combined with letrozole on sex hormones, inflammatory factors, carbohydrate antigen 125 (CA125) and vascular endothelial growth factor (VEGF) in patients with endometriosis. Methods From January 2017 to December 2017, 98 patients with endometriosis admitted in Jia Xing hospital were randomly divided into the observation group (49 cases) and the control group (49 cases). The patients in the control group were only treated with letrozole(1 tablets, 1 times a day for 6 months). The observation group was given letrozole and megestrol acetate (1 tablets, 2 times a day for 6 months). The clinical efficacy of the two groups was compared. The levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), progesterone (P) and CA125 were detected by radioimmunoassay before and after treatment. The levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and vascular endothelial growth factor (VEGF) were detected by double antibody sandwich method before and after treatment. Results The total effective rate of the observation group was 93.88%, which was higher than that of the control group (75.51%) (P<0.05). Six months after treatment, the E2, P, IL-6, TNF-α, CA125 and VEGF of the two groups were significantly lower than before treatment, and the E2, P, IL-6, TNF-α, CA125 and VEGF of the observation group were lower than those of the control group, the differences were statistically significant (P<0.05). Conclusion Dedrogesterone combined with letrozole can effectively relieve clinical symptom, reduce the levels of E2, P, inflammatory factors, CA125 and VEGF in patients with endometriosis.

Key words: Key words: Dizogestrel, Letrozole, Endometriosis