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(Drug information on 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."