Ifosfamide treatment of recurrent or metastatic endometrial stromal sarcomas previously unexposed to chemotherapy: A study of the Gynecologic Oncology Group

Objective: To determine the effectiveness and toxicity of ifosfamide chemotherapy in women with metastatic or recurrent endometrial stromal sarcomas unexposed to other chemotherapy. Methods: In a prospective, multi-institutional phase II study conducted by the Gynecologic Oncology Group, the starting dose of ifosfamide was 1.5 g/m(2) given daily intravenously (IV) for 5 days (reduced to 1.2 g/m(2) daily in patients who had previously received radiotherapy). Mesna (2-mercaptoethane sodium sulfonate) was given IV immediately and at 4 and 8 hours after the administration of ifosfamide. Each dose of mesna was 20% of the total daily dose of ifosfamide. Patients were treated every 3 weeks if blood counts permitted. Therapy was discontinued if there was progression of the cancer or unacceptable toxicity. Results: Twenty-two patients were entered into this study. One was excluded from analysis because of the wrong histologic type, leaving 21 evaluable for response and toxicity. Gynecologic Oncology Group grade 3 or 4 granulocytopenia occurred in four patients (19%), and one patient each experienced Gynecologic Oncology Group grade 4 anemia and genitourinary toxicity. Three patients experienced complete tumor responses and four had partial responses, for an overall response rate of 33.3%. Conclusion: Ifosfamide is active in the therapy of women with chemotherapy-naive metastatic or recurrent endometrial stromal sarcomas.