Parity as an independent prognostic factor in malignant mixed mesodermal tumors of the endometrium

Malignant mixed mesodermal tumors (MMMT) are the most malignant neoplasms known to occur in the uterus. The most important prognostic factors are the extent of tumor at diagnosis, depth of myometrial invasion, and, as regarded by some authors, the sarcomatous component. We report on a retrospective analysis in 83 patients with MMMT. By univariate analysis survival was dependent on stage, depth of myometrial invasion, kind of therapy, age at menopause, and parity. However, the sarcomatous component did not significantly influence survival. Using the multivariate Cox regression analysis stage and parity or depth of myometrial invasion and parity were found to independently predict prognosis. Despite an interval of more than 20 years from the last childbirth to tumor appearance a beneficial influence of parity on the prognosis of MMMT was identified. This is unique in oncology. Especially patients with more than three children formed a subgroup of long-term survivors. It is interesting to note that parity was found by means of a Cox regression analysis to be statistically independent, and no correlation with other classical prognostic factors was detected.