An expert panel of 10 international cancer researchers and
practicing oncologists met in Boston to discuss the past, present,
and future uses of antiestrogens in the treatment of breast cancer.
The first articles in this series, based on the symposium presentations,
focused on the optimal duration of tamoxifen use (Oct, 1996, page
17) and on the noncancer benefits of tamoxifen weighed against
the potential risk of endometrial cancer (Nov, 1996, page 55).
This month, the benign endometrial changes associated with tamoxifen
use are reviewed. The symposium was sponsored by Zeneca Pharmaceuticals.
BOSTON--Although evaluating patients on tamoxifen (Nolvadex) with
endometrial biopsies is appropriate in clinical trials, "we
certainly do not recommend it to all gynecologists in the community,"
said Richard R. Barakat, MD, a gynecologic oncologist at Memorial
Sloan-Kettering Cancer Center.
Tamoxifen is known to have proliferative effects on the endometrium,
Dr. Barakat said. However, hyperplasia in the endometrium represents
a broad spectrum of changes. Endometrial hyperplasia is classified
as simple or complex, with or without nuclear atypia.
"The only real endometrial hyperplas-tic lesion that has
a significant rate of progression to cancer is complex atypical
hyperplasia, which has about a 27% progression rate," Dr.
Barakat said. Only about 1% of untreated simple hyper-plasias
will progress, he added.
Panel members V. Craig Jordan, PhD, DSc, and Vasilios Assikis,
MD, of Northwestern University Medical School, reviewed a series
of reports that examined endometrial histology in women on tamoxifen.
Their analysis showed about a twofold increase in the incidence
of proliferative endometrium, about a threefold increase in endometrial
polyps, and about a 10-fold increase in endometrial hyperplasia,
with tamoxifen use.
Dr. Barakat pointed out that most of these studies involved only
a small number of patients and did not always specify the exact
type of hyperplasia. "In fact, the incidence of complex atypical
hyperplasia appears to be quite low," he said.