Comparison of Current Staging Systems and a Novel Staging System for Uterine Leiomyosarcoma

Abstract

Uterine leiomyosarcoma (LMS) was traditionally staged by modified 1988 International Federation of Gynecology and Obstetrics (FIGO) staging criteria for endometrial adenocarcinoma. Contemporary methods of staging include the 2009 FIGO system for uterine LMS and the 2010 American Joint Committee on Cancer (AJCC) soft tissue sarcoma system. The aim of this study was to compare the accuracy of these 3 staging systems and a novel system in predicting disease-specific survival for patients with uterine LMS. Patients, evaluated at our institution with uterine LMS from 1976 to 2009, were identified. Stage was assigned retrospectively based on operative and pathology reports. Staging systems performance was compared using confidence indices. We identified 244 patients with uterine LMS with sufficient information to be staged by all 3 systems. For each staging method, lower stage was associated with significantly improved disease-specific survival, P < 0.001. Patients with 2010 AJCC stage IA disease (low-grade, ≤5 cm) experienced no disease-specific deaths. We created a novel staging system, which used size and grade to stratify patients with disease confined to the uterus and/or cervix and combined the remaining patients with extrauterine disease as stage IV. Based on confidence index, the 2010 AJCC system and our novel system provided more accurate prognostic information than either of the 2 FIGO systems. Uterine LMS remains a clinically aggressive malignancy. Size and grade provided accurate prognostic information for patients with disease confined to the uterus and/or cervix. Patients with small, low-grade uterine LMS do not benefit from adjuvant therapy.