Objective: The aim of this study was to determine the value of the progesterone challenge test (PCT) in screening for the endometrial pathology of asymptomatic postmenopausal women receiving tamoxifen (TMX).
Methods: A prospective and preliminary study was conducted on 89 postmenopausal women who had been receiving adjuvant treatment for breast cancer with TMX (20 mg/d) for at least 2 years and who had not presented with any episode of postmenopausal metrorrhagia. Transvaginal ultrasound (TVUS), PCT, diagnostic hysteroscopy, and sampling of histologic material were performed on all the women. The validity of the PCT was compared with that of TVUS in screening these women for endometrial pathology, using hysteroscopic biopsy as the gold standard for comparisons.
Results: The study protocol was completed in 82 (92.13%) women. The PCT was negative in 69.5% and positive in 30.4% of the cases. The sensitivity of the PCT for detecting the absence of pathology (atrophic endometrium) in the women was 100% versus 91.6% for TVUS; the positive predictive value for endometrial pathology was 100% versus 85.7% for TVUS; and the negative predictive value for hyperplasic pathology was 100% versus 98.1% for TVUS.
Conclusions: In asymptomatic postmenopausal women receiving TMX, the PCT presents high sensitivity (100% in our series) and high positive predictive value (100%) in the diagnosis of endometrial pathology and a high negative predictive value (100%) for hyperplasic pathology. Its predictive performance is superior even to that of TVUS. Therefore, although this a preliminary study, we consider that the inexpensive PCT could be an efficient method of screening in these women during or before initiation of TMX therapy.