Long-term "protective" effect of aromatase inhibitors on the endometrium of postmenopausal breast cancer patients.
BACKGROUND
Decrement of endometrial thickness was recorded following short-term aromatase inhibitor treatment in breast cancer patients previously treated with tamoxifen. It is necessary to verify if long-term aromatase inhibitor treatment can maintain this phenomenon.


METHODS
Prospective long-term comparison of the last ultrasonographic endometrial thickness measurement taken before discontinuation of long-term tamoxifen treatment in 64 postmenopausal breast cancer patients, with further repeated measurements, performed following administration of aromatase inhibitors.


RESULTS
There was a significant decrement of endometrial thickness, following 36.5 +/- 15.7 months of tamoxifen treatment, from a mean value of 8.7 +/- 5.2 mm, measured at the last ultrasonographic measurement performed before discontinuation of tamoxifen treatment, down to a mean value of 6.2 +/- 4.6 mm, measured following 5.3 +/- 4.8 months of aromatase inhibitor therapy (P < 0.001). Further ultrasonographic studies revealed the same significant trend. In the first ultrasonographic study performed during aromatase inhibitor treatment, five (7.8%) patients demonstrated a significant increase of endometrial thickness. Hysteroscopy revealed a benign endometrial polyp in three patients and atrophic endometrium in the other 2. In 35 patients (54.7%), endometrial thickness was reduced following the administration of aromatase inhibitors and in 24 patients (37.5%) there was no change in endometrial thickness. With longer duration of aromatase inhibitor therapy, more patients showed decrement of endometrial thickness.


CONCLUSIONS
Reversal of endometrial thickening induced by long-term tamoxifen treatment in postmenopausal breast cancer patients is maintained throughout long-term aromatase inhibitor treatment.
Markovitch
O
O
Department of Obstetrics and Gynecology, Meir Medical Center, Kfar-Saba, 44281, Israel.
Tepper
R
R
Fishman
A
A
Aviram
R
R
Cohen
I
I
D000368:Aged; D000886:Anthropometry; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D047072:Aromatase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000628:therapy; D003131:Combined Modality Therapy; D004717:Endometrium / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000648:ultrastructure; D005260:Female; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D011446:Prospective Studies; D017584:Reproductive History; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D013629:Tamoxifen / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors; D014463:Ultrasonography
D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen