Efficacy of Pazopanib in Patients with Metastatic Uterine Sarcoma: A Multi-institutional Study

Purpose: Uterine sarcoma accounts for 3-9% of uterine malignant tumors and has poor prognosis. Pazopanib is an oral multi-kinase inhibitor and the only tyrosine kinase inhibitor which has been approved for metastatic soft tissue sarcoma. In the present study we aimed to evaluate the efficacy of pazopanib in metastatic uterine sarcoma.

Methods: The data of 28 metastatic uterine sarcoma patients receiving pazopanib therapy, who were followed in four oncology centers in Ankara, Turkey between May 2013 and June 2018, were retrospectively analyzed. Patients over 18 years, ECOG performance status ≤ 2, receiving at least one line of chemotherapy for metastatic disease, measurable disease at diagnosis, and histologically proven uterine high grade sarcoma were the inclusion criteria. Progression-free survival (PFS), overall survival (OS), and response rates to pazopanib were retrospectively evaluated.

Results: The median age was 53 years (range, 26-76). The majority of the patients had uterine leiomyosarcoma (LMS) (n=25, 89.3%), 2 (7.1%) had undifferentiated uterine sarcoma (UUS), and 1(3.6%) had high grade endometrial stromal sarcoma (ESS). The most common site of metastasis was lung (n: 21, 75%). The median time for pazopanib therapy was 5 months (0.6-28.3). In 22 patients (78.5%), pazopanib was discontinued due to disease progression, while 2 patients (7.1%) quitted therapy owing to toxicity. Partial response was achieved in 4 patients (14.3%), while 17 (60.7%) had stable disease. Median PFS was 5.2 months (95% CI 2.8-7.5) and median OS was 11.4 months (95% CI 3.4-19.5).

Conclusion: In the present study aiming to assess the real-life outcome of pazopanib-treated patients, we found that pazopanib is efficient in metastatic uterine sarcoma, and our results correspond to the literature.