Long-term survival of patients given hormonal therapy for metastatic endometrial stromal sarcoma.

Endometrial stromal sarcoma (ESS) is a rare neoplasm, mainly observed in premenopausal women. We describe two women 44 and 34 years old at the time ESS diagnosis, who developed lung metastases 3 and 6 years, respectively, after initial treatment: hysterectomy without (case 1) or with oophorectomy (case 2), followed by hormone replacement therapy (HRT) for the latter. Their estrogen (ER) and progesterone receptors (PR) were analyzed biochemically in metastatic lung tissue, yielding respective concentrations of ER 242 and 184, and PR 910 and 100 fmol/mg of cytosol protein. Both patients started treatment with the aromatase inhibitor aminoglutethimide (500 mg qid) after surgery for the first patient and after stopping HRT for the second. Under aromatase-inhibitor therapy, both patients achieved a complete response, patient 1 remains disease- free with 14+ years of follow-up, and patient 2 with 7+ years. Our data suggest that an aromatase inhibitor may be an effective treatment for ESS. Furthermore, routine ER and PR analyses could be useful to predict the response to hormonal therapy in ESS.