A prospective study on the efficacy of oral estrogen in female patients with acromegaly

To evaluate the efficacy and safety of oral estrogen therapy in female patients of childbearing age with uncontrolled acromegaly and to verify the significance of the presence of estrogen receptor α (ER-α) in somatotropinomas.

Prospective study in which biochemical and radiological evaluations were performed at baseline and after six months of treatment with an oral formulation of ethinyl-estradiol 0.03 mg and levonorgestrel 0.15 mg. ER-α was assessed by immunohistochemistry and immunopositivity was considered when it was present in ≥ 1% of cells.

Eight patients with uncontrolled acromegaly were selected. All patients underwent surgery. Four patients were on octreotide LAR 30 mg, two patients were on lanreotide autogel 120 mg, and two patients had active disease after surgery. At the end of follow-up, IGF-I normalized in 3/8 (37%), 2/8 (25%) patients presented with mean IGF-I reduction of 25% but without IGF-I normalization, and 2/8 (25%) did not respond-one had a 13% increase in IGF-I and IGF-I level remained unchanged after treatment in the other. In one patient, treatment was discontinued after 3 months due to side effects (headache), with an IGF-I reduction of 28% but without normalization. Tumor volume increase (41%) was observed in only one patient (the only tumor with positive ER-α expression).

In uncontrolled patients with acromegaly, a trial with oral estrogen can be an option for young women. Oral estrogen was well tolerated, but the somatotropinoma that presented ER-α expression was the only somatotropinoma that presented growth during treatment.