Modification of endometrioma size during hormone therapy containing dienogest

The aim of the present study was to evaluate whether hormone therapy containing dienogest is effective in reducing endometrioma size. A retrospective observational study was conducted on 116 women with endometrioma which was evaluated after 6 and 12 months of either no treatment (n = 46), or hormonal therapy containing dienogest (n = 70), without (DNG; n = 34) or with ethinylestradiol (DNG/EE; n = 36). Median (interquartile range) cyst diameter (23.0 mm (21.0 mm)) and volume (9941.2 mm(3) (14240.1 mm(3))) of untreated were similar to cyst diameter (25.0 mm (14.5 mm) and volume (7587.7 mm(3) (13806.2 mm(3))) of treated women. After 12 months, endometrioma volume did not vary in untreated women (-34.0 mm(3) (55595.0 mm(3)); -0.77% (93.9%)) while it significantly decreased (-5400 mm(3) (15378.7 mm(3)); -100.0% (27.7%); p<.0001) during hormone therapy. Volume decrease was linearly related to endometrioma volume ( R-2 = 0.899, p<.0001). The effect tended to be greater during DNG alone than DNG/EE (-100.0% (0.0%) vs. -87.9% (47.7%); p<.0004). Cyst disappearance was observed in 4.4% of untreated cases and in 57.1% of cases on hormone therapy (p<.0001) (38.9% with DNG/EE and 76.5% with DNG; p<.03). The early diagnosis and treatment of endometrioma with dienogest-based hormone therapy may be effective in controlling cyst growth and in reducing the need for surgery.