Obese women who used the levonorgestrel intrauterine system (LNG-IUS) were nearly three times as likely to achieve a complete response to progestin treatment, along with a 70% reduction in risk of progression to cancer, compared to those who received systemic progestin therapy, according to a retrospective study. Published in the American Journal of Obstetrics and Gynecology, it also concluded that superiority of the LNG-IUS in treatment response rose incrementally with increasing body mass index (BMI), while morbidly obese women derived the highest relative benefit.
“Endometrial hyperplasia is a diagnosis we unfortunately encounter rather frequently in our population with high obesity rates,” said senior author Rachel Mandelbaum, MD, a resident physician in ob/gyn at the University of Southern California in Los Angeles. “However, there are no clear treatment guidelines for the medical management of these patients when hysterectomy is not performed. Knowledge gaps exist with regards to route of progestin therapy, how long to treat, and when and how to resample in follow-up. There is a great need to study these important clinical questions to ensure high quality and effective care for these patients.”
Led by Matsuo Koji, Associate Professor of Obstetrics & Gynecology, the study comprised 245 obese women with a mean age of 36.9 years and a mean BMI of 40.0 kg/m2, all of whom had complex atypical hyperplasia. Participants received either the LNG-IUS (n = 69) or systemic progestin therapy (n = 176) at the Los Angeles County Medical Center between 2003 and 2018.
Women in the LNG-IUS group had higher rates of complete response: 78.7% vs. 46.7%, respectively; adjusted hazard ratio (aHR) = 3.32; 95% confidence interval (CI): 2.39 to 4.62. The LNG-IUS group also had a lower likelihood of progression to cancer: 4.5% vs. 15.7%; aHR = 0.28; 95% CI: 0.11 to 0.73.
In particular, women with class III obesity derived a higher relative benefit from the LNG-IUS in achieving complete response compared to systemic therapy: aHR = 4.72; 95% CI: 2.83 to 7.89.
“The margin of difference between the LNG-IUS and systemic therapy is striking in our study,” Dr. Mandelbaum told Contemporary OB/GYN. “As clinicians, we are aware of many of the benefits of the LNG-IUS compared to systemic progestins; daily patient compliance is not necessary, there are usually fewer side effects and bleeding profile often improves. But, to add this evidence for superior treatment efficacy is a great tool to advocate for LNG-IUS use in appropriate candidates.”