Risk factors for recurrent cases of early-stage uterine sarcoma after complete surgical resection.

BACKGROUND

Uterine sarcoma has an inferior prognosis and high recurrence rate among gynecological malignancies, even in early-stage cases with complete resection. However, the risk factors for recurrence remain poorly understood. This study aimed to identify risk factors associated with recurrence in early-stage uterine sarcoma.

METHODS

Among 97 patients with uterine sarcoma treated at our institution between January 2007 and June 2023, we retrospectively investigated 55 patients of the following five histological types: uterine leiomyosarcoma (ULMS), low- or high-grade endometrial stromal sarcoma (LG-ESS or HG-ESS), adenosarcoma, and smooth muscle tumor of uncertain malignant potential (STUMP). Risk factors were compared between the recurrence and non-recurrence groups using univariate analysis, and recurrence rates, time to recurrence, progression-free survival (PFS), and overall survival (OS) were examined.

RESULTS

The median age of 55 patients was 48 years, and the most common initial symptom was abdominal pain or abdominal mass awareness (29.4%), followed by abnormal bleeding in 25.5% of the patients. The median tumor size was 9.7 cm, and stage I cases were 64.8% of the total. Histological types were 28 ULMS, 13 LG-ESS, 8 STUMP, 5 HG-ESS, and one adenosarcoma. Among stage I cases, ULMS had a recurrence rate of 81.3% with a median time to recurrence of 12.4 months, while LG-ESS had a recurrence rate of 30% with a median time to recurrence of 41.1 months. A high mitotic count was significantly associated with recurrence in stage I ULMS (p = 0.044). Other surgical pathological findings, such as lymphovascular space invasion, MIB-1 positive rate, and necrosis, and surgical factors, such as myomectomy and ovarian preservation, showed no statistically significant differences but were higher in the recurrence cases. The 5-year PFS rates in stage I ULMS and LG-ESS groups were 31.3% and 75%, and the 5-year OS rates were 68.5% and 100%, respectively.

CONCLUSIONS

In stage I ULMS, a high mitotic count was associated with an increased risk of recurrence after complete surgical resection.