Background: Malignant mesenchymal uterine neoplasms are the most aggressive type of primary uterine tumors, with most patients dying within a few years of diagnosis. Thus, it would be very important to define prognostic factors for predicting the malignancy potential of at least some of their subtypes.
Methods: Flow cytometric cell cycle analysis (proliferative activity, DNA ploidy, and DNA index) was performed on archival paraffin embedded blocks from 80 patients with malignant mesenchymal uterine neoplasms (endometrial stromal sarcomas, malignant smooth muscle tumors, and malignant Müllerian mixed tumors). The Cox proportional hazards regression model was used to assess relative effects of the following factors on patient survival: clinical stage, mode of therapy, DNA+proliferative activity, DNA index, histologic type, cellularity, degree of atypia, mitotic activity, and depth of myometrial invasion.
Results: There were 9 low grade stromal sarcomas, 17 high grade stromal sarcomas, 8 smooth muscle neoplasms with uncertain malignant potential, 23 leiomyosarcomas, and 16 homologous and 7 heterologous malignant Müllerian mixed tumors. In univariate analysis for stromal sarcomas, statistical significance was found for DNA ploidy+proliferative activity (P < 0.001), histologic type (P = 0.005), and DNA index (P < 0.001). In multivariate analysis, DNA index appeared to be the only significant parameter influencing patient survival (P = 0.005). In univariate analysis for malignant smooth muscle neoplasms, statistical significance was detected for mitotic activity (P = 0.049) and International Federation of Gynecology and Obstetrics classification (P = 0.021), but in multivariate analysis, clinical stage appeared to be the only significant parameter influencing patient survival (P = 0.032). In univariate analysis for malignant Müllerian mixed tumors, statistical significance was found for the depth of myometrial invasion (P = 0.039), DNA index (P = 0.037), and clinical stage (P = 0.013), but in multivariate analysis, only the depth of myometrial invasion (P = 0.036) and clinical stage (P = 0.025) were of statistical significance.
Conclusions: The most powerful prognostic indicator for stromal sarcomas was the DNA index, for malignant smooth muscle neoplasms it was the clinical stage, and for malignant Müllerian mixed tumors it was the depth of myometrial invasion.