A. Rodatra et al., EFFECT OF TAMOXIFEN ON SERUM ESTRADIOL CONCENTRATIONS AND THE DEVELOPMENT OF ENDOMETRIAL PATHOLOGY IN POSTMENOPAUSAL WOMEN WITH BREAST-CANCER, Menopause, 4(4), 1997, pp. 197-200
Objective: Tamoxifen is used widely as adjuvant therapy for breast can
cer in postmenopausal women. Our objective was to evaluate the effects
of tamoxifen on serum estradiol and the endometrium of postmenopausal
patients with breast cancer attending the Oncology Clinic at Belfast
City Hospital. Design: A prospective study of 48 selected patients wit
h breast cancer on maintenance tamoxifen therapy were assessed. Serum
follicle-stimulating hormone, luteinizing hormone, and estradiol were
measured. Vaginal ultrasound and endometrial biopsy were performed. Th
e patients were divided into two groups: group A, those with amenorrhe
a (n = 34), and group B, those with abnormal vaginal bleeding (n = 14)
. Both groups were matched for age and duration of tamoxifen therapy.
Results: Gonadotrophin levels were comparable between the two groups (
p > 0.05). However, the serum estradiol levels were significantly elev
ated in those with abnormal vaginal bleeding (group B) as compared wit
h the levels in those with amenorrhea (group A; p < 0.01). The mean en
dometrial thickness as measured using vaginal ultrasound was significa
ntly greater in group B (7.2 mm) than in group A (4.4 mm) (p < 0.01).
In group A, all the available endometrial biopsies demonstrated normal
basal endometrium. In group B, the majority of endometrial samples (5
0%) demonstrated a normal endometrial pattern. Endometrial polyps were
found in 43% of the samples from group B, and 7% showed cystic hyperp
lasia without atypia. There were no cases of malignancy in any of the
endometrial biopsies. Conclusions: Our findings suggest that the prese
nce of abnormal Vaginal bleeding in a postmenopausal woman on tamoxife
n therapy may indicate that the estradiol levels are elevated. It seem
s reasonable to suggest that these patients should have their estradio
l levels measured urgently and, if elevated, the rationale for their t
amoxifen therapy reviewed.