Temozolomide in advanced and recurrent uterine leiomyosarcoma and correlation with o6-methylguanine DNA methyltransferase expression: a case series.

INTRODUCTION: Our objective was to retrospectively review temozolomide in advanced and recurrent uterine leiomyosarcoma and to determine if tumor O-methylguanine DNA methyltransferase (MGMT) expression correlated with clinical response.
METHODS: All patients with advanced or recurrent uterine leiomyosarcoma who received temozolomide during treatment were retrospectively identified. Relevant clinical and pathologic data were collected and compared. O-Methylguanine DNA methyltransferase expression was assessed by immunohistochemistry and scored by a gynecologic pathologist blinded to clinical outcomes.
RESULTS: From 1999 to 2008, 9 cases of leiomyosarcoma were diagnosed; 6 patients received temozolomide. Median follow-up was 54 months (range, 4-114 months). There was 1 patient with complete response, 1 durable partial response (27+ months), 3 stable disease (range, 3-10 months), and 1 progressive disease. Overall, 5 out of 6 patients derived clinical benefit. The patient with a complete response recurred 18 months after her last cycle. Median progression free interval was 15.4 months (95% confidence interval, 9.4-21.4). Two patients died of disease. Temozolomide was well tolerated with no dose-limiting toxicities, and no dose adjustments were required in 64 prescribed cycles. The MGMT expression was inversely correlated with response to temozolomide. Patients with tumors negative for MGMT expression had a median progression free interval of 18.5 months compared with 3 months for those whose tumors were positive, although not statistically significant.
CONCLUSIONS: Temozolomide is an easily administered, well-tolerated chemotherapeutic option in advanced or recurrent uterine leiomyosarcomas with a reasonable response rate. Assessment of MGMT expression may identify a subset of patients that will respond optimally to this therapy.