Endometrial carcinosarcoma without myoinvasion.

Objective: Uterine carcinosarcoma without myoinvasion, limited to the endometrial lining/polyp or with no residual uterine disease at the time of hysterectomy, is extremely uncommon, with unknown oncologic outcomes. Thus, this study aimed to evaluate the long-term outcomes of patients with carcinosarcoma without myoinvasion.

Methods: Patients with International Federation of Gynecology and Obstetrics 2009 stage IA carcinosarcoma without myoinvasion who underwent surgery from December 1998 to January 2023 were identified from 11 centers worldwide. Patients were classified by tumor status (limited to the endometrium, limited to polyp, no residual disease in the hysterectomy specimen) and by type of adjuvant therapy (chemotherapy vs no chemotherapy). Survival analysis follow-up was limited to the first 5 years after surgery.

Results: Of 97 patients included, 28 (28.9%) had disease confined to a polyp, 55 (56.7%) to the endometrium, and 14 (14.4%) had no residual disease in the hysterectomy specimen. Patients received observation only (n=16, 16.5%), vaginal brachytherapy alone (n=14, 14.4%), external beam radiation therapy ± vaginal brachytherapy (n=5, 5.2%), chemotherapy ± vaginal brachytherapy (n=51, 52.6%), and chemotherapy and external beam radiation therapy ± vaginal brachytherapy (n=7, 7.2%), whereas adjuvant therapy was unknown in 4 patients (4.1%). A total of 29 patients (29.9%) recurred, mostly with a distant pattern of relapse. The 5-year recurrence-free survival was 63.5% (95% CI 53.4% to 75.4%) and the overall survival was 72.0% (95% CI 62.6% to 82.9%). The median follow-up for patients without recurrence was 56.9 months (interquartile range; 21.8-72.9). No significant differences were observed in recurrence-free survival and overall survival based on status of the tumor (p=.99 and p=.43, respectively). The difference in recurrence-free survival and overall survival was not statistically significant based on the receipt of chemotherapy (p=.08 and p=.07, respectively).

Conclusions: Patients with carcinosarcoma without myoinvasion have a poor prognosis, with a high recurrence rate with distant pattern. The use of chemotherapy did not achieve statistical significance but may be limited by our small series.