Avastin May Be Helpful Before Breast Cancer
WEDNESDAY, Jan. 25 (HealthDay News) -- The addition of the
cancer-fighting medication Avastin to chemotherapy prior to breast
cancer surgery increases the chance that all of the cancer will be
removed, according to new research.
However, when looking at which patients might benefit the most
from this therapy, two recent studies found conflicting results,
and neither study was yet able to address whether or not the
addition of Avastin (bevacizumab) early in the treatment process
would improve survival rates.
Information on survival will be especially important for
defining Avastin's role in early breast cancer treatment. That's
because in November 2011, the U.S. Food and Drug Administration
(FDA) revoked Avastin's approval for the treatment of breast cancer
that has spread to other parts of the body. With metastatic breast
cancers, the agency felt the survival benefits were lacking, and
the drug carries significant risks. Avastin is, however, still
FDA-approved as a treatment for some metastatic colon, brain,
kidney and lung cancers.
"The bevacizumab story is not done. The addition of Avastin to neoadjuvant chemotherapy in women with operable breast cancer increased the rate of women having the disappearance of their breast cancer at the time of surgery," said Dr. Harry Bear, lead author of one of the new studies.
"With more follow-up of these trials and several others, we may find that bevacizumab actually does increase the cure rate. But, it may not be for all breast cancers; it may just be for some," said Bear, a professor and chairman of the division of surgical oncology at Virginia Commonwealth University's Massey Cancer Center in Richmond.
Results of the studies are published in the Jan. 26 edition of
New England Journal of Medicine.
Bear's study included more than 1,200 women who had been
diagnosed with breast cancer. None of the women had yet had surgery
to remove their tumors. All of the women had tumors that were at
least 2 centimeters (about 0.8 inches) in diameter, and none had
The women received chemotherapy before surgery (neoadjuvant
therapy). They were randomly assigned to treatment groups that
included the chemotherapy drugs docetaxel, capecitabine and
gemcitabine in various doses and combinations. They were also
randomly assigned to receive Avastin or not during their first six
cycles of chemotherapy.
The study found that adding capecitabine or gemcitabine to
docetaxel therapy didn't improve response rates. But the addition
of Avastin increased the rate of "pathological complete response"
-- meaning the tumor disappeared before surgery -- from 28.2
percent to 34.5 percent, according to the study.
However, the addition of Avastin also increased the risk of
serious side effects, such as high blood pressure and heart
The second study, conducted in Germany, included almost 2,000
women with an average tumor size of 4 centimeters (about 1.6
inches). As in Bear's study, the women were randomly assigned to
several neoadjuvant chemotherapy groups. In this study, however,
treatment was with docetaxel, epirubicin and cyclophosphamide. They
were also randomly assigned to receive Avastin or not.
Overall, the odds of pathological complete response were
increased by 29 percent with the addition of Avastin. However, when
the researchers looked at tumors by hormone receptor status, they
found that it was primarily women with triple-negative cancers who
showed a significant response to Avastin. Having a triple-negative
breast cancer means that a cancer's growth isn't influenced by
hormones such as estrogen or progesterone. If a tumor is called
hormone receptor-positive, it means that hormones, such as
estrogen, can help fuel that cancer's growth.
In Bear's study, the investigators found Avastin had an effect
on both hormone receptor-positive and hormone receptor-negative
cancers, but there appeared to be slightly more benefit for the
hormone receptor-positive women.
Bear said a number of factors could explain these seemingly
conflicting findings. The differences may have something to do with
the women involved in each study, he said. Some of the women in the
German study had more advanced cancers. And, the chemotherapy
regimens weren't the same, he explained.
Commenting on the findings, Dr. Len Lichtenfeld, deputy chief
medical officer for the American Cancer Society, said that "these
studies suggest that for certain patients, there may be a benefit
to using Avastin prior to surgery for breast cancer."
However, Lichtenfeld added, "what we don't know from these
studies is which women would benefit the most, and we don't have
the long-term follow-up on these women to see if the survival or
the course of the disease is improved."
Both Lichtenfeld and Bear acknowledged that because Avastin
isn't FDA-approved for the treatment of breast cancers, insurance
companies may be reluctant to pay for these treatments outside of a
clinical trial setting.
"There still remain significant questions about the benefits of using Avastin in breast cancer," Lichtenfeld pointed out. "There is an increased risk of side effects, and there's a cost to adding this treatment. Based on these two studies, it's difficult to say whether any particular women should consider this treatment. As with many similar research findings, it's important to talk to your own doctor to get a better understanding of your potential risks and benefits," he added.
To learn more about Avastin, visit the
U.S. National Library of Medicine.
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