Measurement of endometrial thickness by transvaginal ultrasonography to predict pathological response to medroxyprogesterone acetate in patients with grade 1 endometrioid adenocarcinoma

The aim of the present study was to evaluate whether measuring endometrial thickness during fertility-sparing treatment with medroxyprogesterone acetate (MPA) can be a predictive marker for effectiveness in women with endometrioid adenocarcinoma, grade 1 (EmCa, G1). A total of 32 patients with stage IA EmCa, G1 underwent treatment with MPA. Patients were <40 years of age and preferred fertility-sparing treatment. MPA (600 mg/day) with low-dose aspirin was administered orally for 26 weeks. Pathological evaluation was performed by total curettage at weeks 8 and 16 and by fractional curettage at week 26. Patients underwent curative surgery in case of disease progression. Endometrial thickness was measured by transvaginal ultrasonography at weeks 8 and 16. Patients who showed non-complete response (non-CR) had thicker endometrium than that of CR patients at weeks 8 and 16. Receiver operating characteristic analysis revealed cut-off values of 8.3 and 4.7 mm endometrial thickness at weeks 8 and 16, respectively, for non-CR. Endometrial thickness >5 mm at week 16 was an independent factor for prediction of non-CR. Measurement of endometrial thickness during MPA treatment may be useful as a predictive marker for pathological response to MPA in patients with EmCa, G1.