NASHVILLE, TENN. – Ultrasound is a reasonable first step for the evaluation of postmenopausal women with abnormal uterine bleeding and endometrial thickness up to 5 mm, according to James Shwayder, MD, JD.
About a third of such patients presenting with abnormal uterine bleeding (AUB) will have an endometrial polyp or submucous myoma, Dr. Shwayder explained during a presentation at the annual clinical and scientific meeting of the American College of Obstetricians and Gynecologists.
However, recurrent bleeding warrants further work-up, he said.
The 5-mm value is based on a number of studies, which, in sum, show that the negative predictive value for cancer for endometrial thickness less than 4 mm is greater than 99%, said Dr. Shwayder, chief of the division of gynecology and director of the fellowship in advanced endoscopy obstetrics, gynecology, and women’s health at the University of Louisville (Ky.).
“In fact ... the risk of cancer is 1 in 917,” he added. “That’s pretty good ... that’s a great screening tool.”
The question is whether one can feel comfortable foregoing biopsy in such cases, he said, describing a 61-year-old patient with a 3.9-mm endometrium and AUB for 3 days, 3 weeks prior to her visit.
There are two possibilities: The patient will either have no further bleeding, or she will continue to bleed, he said, noting that a 2003 Swedish study provides some guidance in the case of continued bleeding (Am J Obstet Gynecol. 2003;188:401-8).
The investigators initially looked at histology associated with endometrial thickness in 394 postmenopausal women referred for AUB between 1987 and 1990. Both transvaginal ultrasound and dilatation and curettage were performed, and the findings were correlated.
“But they had the rare opportunity to take patients who had benign evaluations and bring them back 10 years later,” Dr. Shwayder said. “What they found was that, regardless of the endometrial thickness, if it was benign initially and they did not bleed over that 10-year period, no one had cancer.”
However, among the patients followed for 10 years who had recurrent bleeding, 10% had cancer and 12% had hyperplasia. Thus, deciding against a biopsy in this case is supported by good data; if the patient doesn’t bleed, she has an “incredibly low risk of cancer,” he said.
“If they bleed again, you’ve gotta work ‘em up,” he stressed. “Don’t continue to say, ‘Well, let me repeat the ultrasound and see if it’s thinner or thicker.’ No. They need to be evaluated.”
Keep in mind that if a biopsy is performed as the first step, the chances of the results coming back as tissue insufficient for diagnosis (TIFD) are increased, and a repeat biopsy will be necessary because of the inconclusive findings, Dr. Shwayder said. It helps to warn a patient in advance that their thin endometrium makes it highly likely that a repeat biopsy will be necessary, as 90% come back as TIFD or atrophy.
Importantly, though, ACOG says endometrial sampling should be performed first line in patients over age 45 years with AUB.
“I’ll be honest – I use ultrasound in these patients because of the fact that a third will have some sort of structural defect, and the focal abnormalities are things we’re not going to be able to pick up with a straight biopsy, but we have to be cognizant that the college recommends biopsy in this population,” Dr. Shwayder said.