The value of transvaginal ultrasonography in the endometrial evaluation of breast cancer patients using tamoxifen.

OBJECTIVE To estimate the value of transvaginal ultrasonography (TVU) in evaluating the endometrium in breast cancer patients on tamoxifen, and to investigate the relationship between TVU and histologic endometrial findings in these patients. SUBJECTS AND METHODS 107 breast cancer patients taking tamoxifen were included in this study. TVU was performed twice for each patient: prior to starting tamoxifen therapy and 1 year after taking tamoxifen. An endometrial thickness of >or=5 mm was considered abnormal. Endometrial biopsy was performed at the same time the 2nd TVU was done. The patients were divided into 2 groups: symptomatic (group A) and asymptomatic (group B), based on whether or not there was abnormal vaginal bleeding. RESULTS 31 patients (29%) were symptomatic, while the remaining 76 (71%) were asymptomatic. The endometrial thickness increased after 1 year of taking tamoxifen from 4.84+/-0.4 mm to 6.34+/-2.1 mm in group A and from 4.73+/-0.3 mm to 5.67+/-1.95 mm in group B (p>0.05). Endometrial biopsy revealed 77 (71.96%) atrophic endometria and 21 (19.62%) polyps. A comparison between the 2 groups showed a significant difference in patients with endometrial atrophy and atypical hyperplasia. Patients who had an endometrial thickness of >5 mm had a significantly higher prevalence of atypical hyperplasia (p=0.003) and polyps (p=0.041). The sensitivity, specificity, positive predictive and negative predictive values of TVU were 63.3, 28.57, 25.67 and 66.66%, respectively. CONCLUSION Our study showed a discrepancy between TVU and endometrial biopsy findings, due to the specific histology of the endometrium in breast cancer patients using tamoxifen. Due to this discrepancy, TVU alone is not an effective screening test for endometrial pathology and its application alone might lead to an undesirably high frequency of invasive diagnostic procedures.