[Pulmonary metastases from endometrial stromal sarcoma may benefit from hormone therapy]

Long-term treatment of residual or recurrent low-grade endometrial stromal sarcoma with aromatase inhibitors: A report of two cases and a review of the literature

Endometrial stromal sarcoma (ESS) occurs rarely and accounts for only 0.2% of all uterine malignancies. ESS usually expresses estrogen and progesterone receptors, and is regarded as hormone-sensitive. Due to the rarity of these tumors, there are only few case series on the use of aromatase inhibitors in the treatment of low-grade ESS. The present study reports the cases of two patients with residual or recurrent low-grade ESS who experienced long-term disease-free survival following treatment with letrozole. The study also reviews the literature with regard to the data on aromatase inhibitors used in patients with low-grade ESS. In total, 30 patients with recurrent or residual low-grade ESS who were treated with aromatase inhibitors were identified, including the present cases. Among the 30 patients, the overall response rate of advanced low-grade ESS to aromatase inhibitors was 77.4% (complete response, 25.8%; partial response, 51.6%) and the disease control rate was 90.3%. The response rate of first-line treatment was similar to that of second-line therapy or higher (84.6 vs. 72.2%; P=0.453). Duration of aromatase inhibitor treatment ranged from 1.5 to 168 months (median, 26.5 months). The aromatase inhibitors showed minimal adverse effects. In conclusion, aromatase inhibitors, particularly third-generation drugs, are a well-tolerated class of medications that are effective in the treatment of advanced low-grade ESS, with a favorable toxicity profile.

Uterine Sarcoma and Aromatase Inhibitors: Tom Baker Cancer Centre Experience and Review of the Literature

Objectives

Uterine sarcomas are a rare group of mesenchymal tumors with a poor prognosis and aggressive biology. Standard treatment involves surgical staging. The role of further adjuvant treatment is unclear. The goals of this study were to determine the response rates to treatment of patients with uterine sarcomas and to review the currently available literature on the use of aromatase inhibitors (AIs).

Materials and Methods

We performed a retrospective analysis on all patients with uterine sarcoma treated with an AI between 2000 and 2010 at the Tom Baker Cancer Centre in Calgary, Alberta.

Results

Four patients with endometrial stromal sarcoma and 3 patients with leiomyosarcoma received treatment with an AI. A literature search resulted in 10 case reports and 4 retrospective studies of patients with endometrial stromal sarcoma and 1 case report and 2 retrospective studies of patients with leiomyosarcoma. On the basis of the available literature, combined with the current findings, the overall response rate of endometrial stromal sarcoma to AIs is 67% (complete response of 7% and partial response of 60%), and the partial response rate of leiomyosarcoma to AIs is 11%, with no reported complete responses.

Conclusions

Aromatase inhibitors are a well-tolerated class of medications that are effective in the treatment of endometrial stromal sarcomas. These medications may also have a role to help stabilize disease progression in the treatment of leiomyosarcoma. More large, prospective, multicentered trials will be needed to clarify this issue.