NEW ORLEANS--In presentations at the Society of Gynecologic Oncologists
meeting, Canadian researchers confirmed a small increased relative
risk for uterine cancer in patients taking tamoxifen (Nolvadex),
while investigators from Memorial Sloan-Kettering Cancer Center
showed that office endometrial biopsies may be sufficient to protect
tamoxifen users by findings abnormalities early.
For their metaanalysis, researchers at the Hamilton Research Cancer
Center, Ontario, reviewed 13 trials, including 8 randomized controlled
trials involving 4,449 patients, said William Boyd, MD, who is
now with the National Maternity Hospital, Dublin, Ireland. Analysis
was performed on the entire group and again after adjustments
to exclude women who lacked a uterus or were postmenopausal.
Putting Risk into Perspective
For both the adjusted and nonadjusted analyses, the relative risk
for uterine cancer was 2.81 for breast cancer patients receiving
tamoxifen for 1 year or more. To put this into perspective, Dr.
Boyd pointed out that the relative risk of patients taking unopposed
estrogen has been shown to be 2.3.
"This is slightly lower than our patients on tamoxifen,"
Dr. Boyd said, adding that most of the endometrial cancers in
the tamoxifen group were early, low-risk lesions.
Dr. Boyd recommended that all patients on tamoxifen who are having
abnormal vaginal bleeding undergo endometrial biopsy and long-term
follow-up. "In the asymptomatic patient," he added,
"the picture is less clear."
Richard Barakat, MD, of Memorial Sloan-Kettering, reported that
monitoring for endometrial cancer with office biopsies will safeguard
the majority of patients taking tamoxifen.
"All hyperplastic lesions were detected in patients having
at least 12 months of tamoxifen exposure," he said. "Longer
follow-up is required to determine the value of routine endometrial
biopsies, but this study provides some confirmation that office
biopsies can safely detect abnormalities in these patients."