Mirenas against malignancy: an alternative to operative management

Complex atypical hyperplasia is a recognised precursor to endometrial cancer, the most common gynaecological cancer of the Western World, with hysterectomy being the first line of management. With the increasing elderly population size and BMI, optimal surgical management can be challenging in a sub-set of patients. Levonorgestrol releasing IUS system (Mirena coil) has been identified as a treatment for those unsuitable for surgical management.

To assess the efficacy of Mirena coils in the treatment of endometrial cancers and complex atypical hyperplasia in our patient population.

Retrospective analysis of all type 1 endometrial cancers and CAH diagnosed in Tayside from April 2011 to March 2016 (duration 5 years) managed by a Mirena coil. Primary outcome was resolution of malignancy on biopsy. Secondary outcome was continuation of treatment.

Two hundred nineteen out of 245 eligible endometrial cancers and 38 of 41 CAH case notes were available for assessment. A Mirena coil was the primary mode of treatment in eight endometrial cancers (3.6%) and 18 cases of CAH (47.4%). Of the eight endometrial cancers treated, five (62%) continued with the Mirena coil as the primary mode of treatment. Two patients died during their follow-up due to unrelated illnesses and one patient proceeded to hysterectomy due to the absence of progestogenic effect on repeat Pipelle biopsy at six months (12.5%). Four patients have been followed for one year and of those; two showed no evidence of malignancy, one was unable to be biopsied and the last showed persistent disease but was too frail for intervention. At two-year follow-up, two patients remain with one showing disease recurrence. Thirteen patients (87%) have continued to use the Mirena as management of CAH out of 18 treatments. Of the five patients who did not continue with the IUS; two patients had progressive disease, despite the coil (11%), two patients lost enough weight to proceed to hysterectomy and one patient died unexpectedly. Medical co-morbidities and BMI were the main cited reasons for proceeding with the IUS as the primary treatment. Average BMI of endometrial cancer cases was 43.9 and 45.1 for CAH.

Mirena coil is effective in treating or controlling the progression of endometrial malignancy in the subgroup of patients where there is an increased risk associated with definitive surgery. The treatment failure rate appears to be consistent at about one-tenth of the cohort of women with both endometrial cancers and complex atypical hyperplasia.