News

No advantage in screening for endometrial cancer

Scott Gottlieb, New York

No advantage exists in routine endometrial screening for patients with breast cancer who are being treated with tamoxifen, according to two new studies.

Although tamoxifen cuts the risk of breast cancer in some women, it also raises the risk of endometrial cancer. As a result, patients taking the drug often undergo invasive and somewhat painful biopsies and ultrasound examination of the uterine lining.

The new studies report that these commonly used screening methods are no more effective at diagnosing early endometrial cancer in these patients than watching for abnormal vaginal bleeding. Researchers found that with high rates of false positive results, the risks from both endometrial biopsy and transvaginal ultrasonography far outweigh the benefits (Journal of Clinical Oncology 2000;18:3459-63, 3464-70).

In the first study, led by Dr Richard Barakat, associate chief of gynaecology at Memorial Sloan-Kettering Cancer Center in New York, the researchers prospectively followed 159 premenopausal and postmenopausal patients with stage I or stage II breast cancer who were starting tamoxifen therapy.

The women, with a median age of 50, had an endometrial biopsy every six months for two years, then annually for three years. At a median three years, the patients had undergone 635 endometrial biopsies, 13% of which were insufficient for diagnosis. In total, 26% of the women underwent dilation and curettage for abnormal endometrial biopsies, persistent bleeding, or adnexal masses. Results were negative in three cases.

The remaining diagnoses were polyps, progesterone decidualisation, complex hyperplasia, abnormal histiocytes, and simple hyperplasia. Of the three hysterectomies performed, only one (from a patient with abnormal bleeding) showed malignant pathology.

The authors wrote: "Breast cancer patients on tamoxifen are anxious about developing a second cancer. While it may seem beneficial to order a battery of screening tests, if these screening tests do not have proven records of efficacy, then they might feed, rather than alleviate, these anxieties and lead to unnecessary procedures."

In the second study, Dr Bernd Gerber and colleagues at University of Rostock, Germany, compared 247 postmenopausal patients with breast cancer who were being treated with tamoxifen with 98 controls. Patients underwent transvaginal ultrasonography every six months for up to five years. Those found to have homogeneous endometrium thickening greater than 10 mm were screened with ultrasonography every three months.

Endometrial thickness grew significantly in the treated women, compared with the controls. Of the asymptomatic patients with suspect endometrial tissue, 52 underwent hysteroscopy and dilation and curettage, with four resulting in uterine perforation. Diagnoses were atrophy, polyps, hyperplasia, and cancer.

Diagnoses were statistically indistinguishable for the 20 patients who reported bleeding. There was one asymptomatic polyp and one case of symptomatic hyperplasia in the control group.

About 0.002% of women who are taking tamoxifen will develop endometrial cancer, and about 15% of these cancers results in early death. The studies show that routine biopsy or ultrasonography is no more effective at signalling early signs of cancer than abnormal vaginal bleeding is.

"I think many, many doctors in this country subject their patients to these screening tests, but the problem is that it often leads to unnecessary procedures," Dr Barakat said.