Avastin May Be Helpful Before Breast Cancer Surgery

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 the
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 metastatic cancer.

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 problems.

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.

More information

To learn more about Avastin, visit the U.S. National Library of Medicine.