New Treatment for Young Breast Cancer Survivors
Drug appears more effective than tamoxifen at reducing recurrence in premenopausal women: study
There was a 34 percent reduction in the risk of breast cancer recurrence in the exemestane group compared to the tamoxifen group. The study also found a 22 percent decrease in the risk of cancer spreading to other parts of the body.
"This definitely does show that using an aromatase inhibitor is clearly superior than using tamoxifen," said Dr. Larry Norton, deputy physician-in-chief for Breast Cancer Programs and medical director of the Evelyn H. Lauder Breast Center at Memorial Sloan Kettering Cancer Center in New York City. "It provides an important option for these patients."
Reported side effects were similar to those in previous studies that compared aromatase inhibitors and tamoxifen in postmenopausal women, and differed depending on the drug.
Despite the side effects, only 14 percent of the participants completely stopped the treatments early in the five-year trials. That's an adherence rate higher than what is seen in everyday practice, the researchers said. Previous studies suggest that many breast cancer survivors stop taking preventive hormone therapy before the recommended time.
Norton noted that younger breast cancer survivors might be more likely to take their post-treatment medications as directed if they had an alternative to tamoxifen, which is known to increase a woman's risk of endometrial cancer.
The five-year overall survival rates were high in both groups -- 95.9 percent in the exemestane group and 96.9 percent in the tamoxifen group. Longer follow-up is needed to get a better idea of the impact these two treatments will have on long-term survival, the researchers noted.
"Where the study stands right now, the women who got the Aromasin have had a delay in the recurrence of the disease, but they haven't necessarily had an improvement in survival," Lichtenfeld said.
Lichtenfeld and Norton said follow-up research needs to compare exemestane plus ovarian suppression directly with tamoxifen alone, since tamoxifen can be used without ovarian suppression to treat younger breast cancer survivors.
"My sense is in terms of practical implications, I suspect some physicians will change their treatment plans based on this, but I don't expect widespread change," Lichtenfeld said. "It's going to take more time, more understanding, and a comparison of the newer approach to the standard approach."
A second study, also scheduled to be presented on Sunday at the ASCO meeting, looked at using a combination of two treatments -- trastuzumab and lapatinib -- after surgery for a certain type of breast cancer. The study found that for breast cancers known as HER2 positive breast cancers, the drug lapatinib didn't make a significant difference in disease-free survival after four years.
In addition, the combination therapy led to an increased risk of side effects.
The researchers were surprised that lapatinib didn't add any benefit, but were encouraged that trastuzumab appears to work well on its own in women with early HER2 positive breast cancers after surgery.