Introduction/Background*Uterine carcinosarcoma (UCS) is a rare and aggressive subtype of endometrial cancer with carcinomatous and sarcomatous elements. It comprises less than 5% of all uterine malignancies but carries the worst prognosis. The rarity of this disease and its inclusion in heterogenous groups with other rare uterine neoplasms has resulted in limited and unclear evidence to guide best practice. Our aim was to review the characteristics, treatment and outcomes of UCS cases across two public gynaeoncology units and five private gynaeoncology practices in Melbourne over 26 years.

Methodology A retrospective observational study was conducted where UCS cases were identified from hysterectomy pathology records between 1994 and 2020 inclusive. Patient demographics, treatment details, recurrence and survival data were extracted from patient records. Ethics exemptions were obtained from each of the involved institutions.

Result(s)*208 cases of UCS were identified. The overall recurrence rate was 26.0% and the overall death rate was 60.1%. Increasing age at diagnosis was associated with an increased risk of death (adjusted OR 1.04, 95% CI 1.01-1.08, p=0.019). Risk of death was highest in Stage III disease (adjusted OR 4.37, 95% CI 1.67-11.40). Recurrence was a strong determinant of death, with an adjusted OR of 7.58 (p<0.001). These predictors of survival were independent of modality of adjuvant therapy.

Conclusion*This is the largest Australian series of homogenous UCS cases to date, and one of the largest cohorts worldwide. This adds important information to the existing body of evidence regarding UCS.