Specificity of the lactate dehydrogenase isoenzyme index as a preoperative screen for uterine sarcoma before myomectomy.

Objective: To evaluate the applicability of the Uterine mass Magna Graecia (UMG) risk index (elevation defined by a lactate dehydrogenase isoenzyme index >29) in women undergoing surgery for benign fibroids and to determine whether other factors were associated with an elevated index. An elevated UMG index has been reported to be associated with an increased risk of uterine sarcoma in Italian women.

Design: Retrospective cohort study.

Setting: University fibroid center.

Patients: All women presenting from July 1, 2013, through June 30, 2019, with fibroids who had lactate dehydrogenase isoenzymes collected and surgery performed.

Interventions: Calculation of UMG index.

Main Outcome Measure: Applicability of UMG index.

Results: Of 272 patients initially identified, 179 met inclusion criteria, 163 with UMG index ≤29 and 16 with UMG index >29. There were no cases of uterine sarcoma. Race, age, and presence of endometriosis, adenomyosis, or degenerating fibroids were not predictors of elevated UMG index. Body mass index (BMI) was positively associated with elevated UMG index. Specificity of UMG index to exclude uterine sarcoma was 91.1% (163/179) and higher in non-obese (BMI<30; 95.1%) than obese women (85.5%).

Conclusion: A previously reported UMG index cutoff of 29 had a specificity of 91.1% (higher with normal BMI and lower when obese) in our patient population. Although lower than previously reported, the index could be a useful initial method of preoperative screening of women with symptomatic fibroids. Higher BMI appears to be associated with elevated UMG indices, increasing the false-positive rate in obese women.