Prognosis of surgically staged FIGO IA uterine carcinosarcoma without myometrial invasion (503)

Abstract

<b>Objectives:</b> Uterine carcinosarcoma (UCS) is a rare and aggressive cancer with a poor prognosis. UCS limited to the endometrial lining, polyp, or with no residual uterine disease at the time of hysterectomy is an uncommon clinical entity. To date, the oncological outcomes of these patients are poorly understood, and there is no consensus on standard treatment. Thus, this study aimed to evaluate the long-term outcomes of UCS patients with the above characteristics. <b>Methods:</b> We retrospectively identified FIGO stage IA UCS with spread limited to the endometrial lining, polyp or with no residual uterine disease, who underwent surgical staging, including hysterectomy, bilateral salpingo-oophorectomy, and lymph node assessment (sentinel or systematic pelvic ± para-aortic lymphadenectomy), at an academic referral center between January 2009 and July 2021. Descriptive statistics and the Kaplan-Meier method were used for analysis. <b>Results:</b> Thirteen patients with UCS stage IA were included. The median age was 68 years (range: 58-83). Five patients had disease confined to a polyp, three had surface spread, and five had no disease in the hysterectomy specimen (tumor limited to the biopsy). Lymphovascular space invasion was not identified in any of the patients. Postoperative management included observation (<i>n</i>=3, 23.1%), vaginal brachytherapy (VB) only <i>(n=7,</i> 53.8%), pelvic external beam radiation (EBRT) therapy (<i>n</i>=1, 7.7%), and combined chemotherapy and VB (<i>n</i>=2, 15.4%). The one patient still receiving postoperative VB at the time of this analysis was not considered for survival outcomes. The two patients who received combined adjuvant chemotherapy and VB did not experience recurrence after 5.6 and 6.3 years of follow-up. The median follow-up time for the remaining ten patients who received radiation therapy alone (VB or EBRT) or observation was 4.0 (IQR: 1.6-8.1) years. Four patients of these ten patients experienced recurrences (Table 1). There were three peritoneal and one isolated lymphatic recurrence with no vaginal cuff recurrences. Among patients with recurrence, two (50%) died of disease despite salvage chemotherapy. Among these ten patients, the 3-year progression-free survival and overall survival were 55.6% (95% CI: 31.0-99.7) and 77.8% (95% CI: 54.9-100.0), respectively. Table 1 <b>Conclusions:</b> Patients with early MMMT have a relatively high recurrence rate in the current series. Decisions regarding adjuvant therapy and risk factors for recurrence remain unclear. The benefit of adjuvant treatment in improving overall survival needs to be determined. We are expanding our population to answer the above questions to gain more information.