Clinico-pathological characteristics and survival outcome associated with uterine leiomyosarcoma variants:...

Epithelioid and myxoid types represent uterine leiomyosarcoma variants, and their clinico-pathologic characteristics and survival outcomes have been under-studied because of their rarity. The objective of this study was to assess clinico-pathologic characteristics and survival associated with uterine leiomyosarcoma variants.

This retrospective cohort study queried the Commission-on-Cancer's National Cancer Database. The study population included 7410 patients with uterine leiomyosarcoma, including conventional, epithelioid, and myxoid types, who had primary hysterectomy from 2010 to 2022. Demographic characteristics were assessed using descriptive analysis; overall survival was assessed using a multivariable Cox proportional hazards regression model.

Epithelioid and myxoid types were reported in 478 (6.5%) and 327 (4.4%) patients, respectively. The proportion of the epithelioid variant increased from 5.5% in 2010-2014 to 7.8% in 2019-2022 (p = .005). The epithelioid type was associated with higher rates of lympho-vascular space invasion (33.1% vs 22.0%-23.7%) and nodal metastasis (6.9% vs 3.4%-3.6%), whereas the myxoid type was associated with a higher rate of stage I disease (64.5% vs 56.1%-58.7%) (all, p < .05). Compared with the conventional type, the epithelioid type was associated with improved overall survival (adjusted hazard ratio [aHR] 0.87, 95% confidence interval [CI] 0.75 to 0.99) including stage I (aHR 0.75, 95%CI 0.60 to 0.93) and stage III (aHR 0.59, 95% CI 0.39 to 0.91) disease; the myxoid type was also associated with improved overall survival (aHR 0.68, 95%CI 0.57 to 0.82) including stage I (aHR 0.62, 95% CI 0.47 to 0.82) and stage IV (aHR 0.60, 95% CI 0.41 to 0.88) disease. Across all three types, larger tumor size, lympho-vascular invasion, and higher stage were associated with decreased overall survival, with the survival impact of larger tumor size being more prominent in variants. For stage II to IV epithelioid type, adjuvant chemotherapy was associated with improved overall survival (aHR 0.43, 95% CI 0.29 to 0.64).

The results of this cohort study suggest that uterine leiomyosarcoma variants (epithelioid and myxoid) exhibit distinct histopathologic characteristics and survival compared with the conventional type. These data also endorse the importance of accurate diagnosis, research inclusion criteria, and development of collaborative networks.