Analysis of clinicopathologic prognostic factors for 157 uterine sarcomas and evaluation of a grading score validated for soft tissue sarcoma

BACKGROUND: Uterine sarcomas (US) are rare and carry a poor prognosis characterized by high rates of local recurrence and metastasis. The aim of this study was to test, for what the authors believe was the first time with US, the prognostic impact of the histologic grade validated by the French Federation of Anticancer Centers (FNCLCC) for soft tissue sarcomas (STS). The grade is the sum of the scores allocated for three major histologic criteria: tumor differentiation, mitotic count, and tumor necrosis. Other histologic and clinical factors were tested as well. METHODS: The study included 157 patients in whom 78 leiomyosarcomas (LMS), 52 malignant mixed müllerian tumors (MMMT), and 27 endometrial stroma sarcomas (ESS) were documented. RESULTS: The median follow-up was 54 months (range, 6-230 months). The median OS and EFS were 33 and 13 months, respectively. The FNCLCC grade validated in soft tissue sarcomas was not a prognostic factor for survival or relapse for any of the US histologic subtypes. For LMS, stage and mitotic count were the only factors that had an influence on survival and relapse. For MMMT, stage and age were the only prognostic factors, and none of the histologic criteria impacted on the outcome. For ESS, the grade defined by Norris and Taylor was an important prognostic factor, particularly for survival. CONCLUSIONS: The FNCLCC grading score could not be used as a prognostic indicator for uterine sarcomas. The diagnosis of US is in itself an unfavorable prognostic factor, except when the diagnosis is low grade ESS.