Estimating risk for unexpected uterine leiomyosarcoma on the basis of uterine weight and age

Purpose of investigation: The aim of the study was to estimate an incidence rate based on uterine weight and age for unexpected uterine leiomyosarcoma (ULMS) in patients with presumed uterine leiomyoma (UL) who had undergone total laparoscopic hysterectomy (TLH) or laparoscopic-assisted vaginal hysterectomy (LAVH) or laparoscopic supracervical hysterectomy (LSH) or laparoscopic myomectomy (LM). Materials and Methods: Patients aged 18-64 years who had diagnoses of presumed benign ULs and had undergone TLH or LAVH or LSH or LM between 2002 and 2013 (n = 21,600) from the ClinformaticsTM Data Mart Database were included in this study. Uterus size was identified by specific Current Procedural Terminology (CPT) codes from patients' medical claims and age were stratified into four groups: 18-34, 35-44, 45-54, and 50-64 years. Results: The overall incidence of unexpected ULMS was 1.39 cases per 1,000 (one in 720). The incidence was 1.14 per 1000 (one in 874) in the patients with uteri ≤ 250 grams, whereas it was 2.20 per 1000 (one in 454) in the patients with uteri > 250 grams. After age stratification, the rate was 1.31 cases per 1000 (one in 765) in 35-44 age group, 1.26 cases per 1000 (one in 792) in 45-54 age group, and 3.78 cases per 1000 (one in 265) in 55-64 age group. No unexpected ULMS was found in the patients aged 18-34 years. The patients aged 55-64 years were at a higher risk with an adjusted odds ratio of 3.41 [95% CI 1.22-9.52, p = 0.03] when comparing to patients aged 18-44 years. Uterine weight was marginal significantly (p = 0.08) associated with the incidence rate of unexpected ULMS after adjustments. Conclusion: In this dataset evaluation, the risk of unexpected ULMS was lower among the patients with uteri ≤ 250 grams when compared to those with uteri > 250 grams. In addition, age substantially influenced the incidence of unexpected ULMS. According to the findings obtained from the database, uterine weight and age would be useful triage parameters in estimating more accurate risk of encountering with unexpected ULMS. It also has potential to improve informed consent process.