Other rare uterine sarcomas: Adenosarcoma, endometrial stromal sarcoma, STUMP

Uterine sarcomas are rare entities, representing only 1% of all gynecologic malignancies, and 3% of all uterine cancers. Uterine sarcomas are comprised of different subtypes, the most common being uterine leiomyosarcoma (25%–60% cases), endometrial stromal sarcoma (10–20% cases), high-grade undifferentiated sarcoma (3%–5% cases), and uterine adenosarcoma (5–9% cases). The mortality rate associated with uterine sarcomas is much higher than their endometrial cancer counterparts, which has been mostly driven by high-risk uterine leiomyosarcoma. Five-year overall survival rates have been reported between 25% and 80%, depending on sarcoma histologic subtype and stage. There have been no significant differences in incidences of these rare uterine sarcomas by ethnicity. Given the limited numbers of patients that incur this diagnosis annually, challenges exist in preoperative diagnosis, workup, and treatment of these rare tumors. Universal adoption of adjuvant treatment strategies following surgical management has also been limited given lack of prospective clinical trials in these tumors. Thus, majority of treatment recommendations have been based on review of available data and consensus agreements. In this chapter, we will focus specifically on the rare uterine sarcoma subtypes of adenosarcoma, endometrial stromal sarcoma, and smooth muscle tumors of uncertain malignant potential (STUMP).