Tamoxifen Still Promoted for Many Breast Cancer Cases
Tamoxifen helps prevent breast cancer in women at high risk for the disease who have also had their ovaries removed as part of a hysterectomy, says a study in the Journal of the National Cancer Institute.
Commenting
on the new findings, Dr. Jay Brooks, chairman of hematology/oncology
at Ochsner Health System in Baton Rouge says this "reaffirms
that tamoxifen is still a tremendous drug for prevention
of breast cancer in women who are at a high risk for
development of the disease.”
The initial findings of the Italian clinical trial found tamoxifen offered no reduction in women's risk for breast cancer. Other European trials, some of which looked at women with different risk profiles, had not found a reduction either.
An earlier and much larger US study, the National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial, had shown that tamoxifen could cut the risk of estrogen-receptor-positive breast cancer - tumors that grow in the presence of estrogen.
In fact, that trial was halted early, because the risk reduction in invasive breast cancer was so striking.
In the latest study, the authors presented 11-year follow-up data on more than 5,400 women who had undergone a hysterectomy (including having both ovaries removed) and who had been randomly assigned to receive tamoxifen or a placebo (inactive substance) for five years.
Ovaries make estrogen, so removing them ensures that no extra estrogen - which can fuel some breast cancer tumors - is being produced.
For women at low risk for breast cancer, disease rates were similar whether or not they took tamoxifen, the researchers report.
The situation was different for higher-risk women. In that case, women taking tamoxifen had lower rates of hormone-receptor-positive breast cancer than those taking a placebo.
There was also a greater reduction in risk for tumors that were both progesterone- and estrogen-receptor positive, than for tumors which were estrogen-receptor positive and progesterone-receptor negative.
Women in the tamoxifen group also had more side effects, including hot flashes and heart problems. These are noted side effects of the medication. A woman's cardiac risk needs to be assessed before she is started on tamoxifen, the authors state.
The new study points to the pioneering work that the NSABP did back in the 1990s, says Dr. Brooks.
"Tamoxifen is still an excellent drug for prevention of breast cancer and is underutilized," he
adds.
Another expert says newer medications can help, too.
"Tamoxifen does decrease the risk of invasive breast cancer," says Dr. Alison Estabrook, chief of breast surgery at St. Luke's-Roosevelt Hospital in New York City. "We're
hoping that the new aromatase inhibitors which are
being tried now for prevention will reduce the risk
of breast cancer, which they should."
Aromatase inhibitors, which lower the amount of estrogen in the body by blocking a key enzyme, have far fewer side effects than tamoxifen.
Another medication, raloxifene, also has fewer side effects but does not prevent noninvasive breast cancer, whereas tamoxifen works on both, notes Dr. Brooks.
Always consult your physician for more information.
