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Alteration of the effects of
cancer therapy agents on breast cancer cells by the herbal medicine black
cohosh.
Sara Rockwewll, Yanfeng Liu, Susan Higgins.
Black Cohosh: Effects on Chemotherapy ----- Good News and Bad News
May 3, 2005 SOURCE: denvernaturopathic.com
Subject: Extracts of Black Cohosh can change the cytotoxicity of
chemotherapy.
Black Cohosh or to use the scientific name, Cimicifuga racemosa, is a
popular herb for relieving menopausal symptoms, especially hot flashes.
Women undergoing chemotherapy for breast cancer are often thrown into
menopause as a side effect of treatment. When they go into menopause
suddenly the symptoms experienced can be very pronounced and they are
desperate for relief.
Cimicifuga is generally considered safe to use with
breast cancer and many of these women end up taking it. A new study just
published in Breast Cancer Research should make us pause and reconsider
this option.
The researchers, working at the Cancer Center at Yale University, examined
the effect of Cimicifuga extracts on cancer cells in combination with
various chemotherapy drugs.
Results varied. With some drugs the
combination increased the effectiveness of the drug, with other drugs,
effectiveness decreased. No change was seen with radiation treatments.
The Cimicifuga extracts increased the cytotoxicity of Doxorubicin
(Adriamycin) and Docetaxel (Taxotere) but decreased the cytotoxicity of
Cisplatin or 4-HC (an analog of cyclophosphamide).
The effect of the Cimicifuga with Doxorubicin was not mild. In
measurements of surviving fractions of breast cancer cells incubated with
Doxorubicin adding the Cimicifuga decreased the surviving faction from 1 in
100 to 1 in 10,000 or from 10-2 to 10-4. That's a hundred-fold increase in
the effectiveness of doxorubicin!
Interestingly the researchers did not leap for joy with excitement as they
reported these findings. They acknowledged that increasing the cytotoxic
effect is attractive but they expressed concern that the combination might
increase the undesirable side effects on the bone marrow.
We aren't as
worried as they are.
With other herb/drug combinations that increase cancer cell death, the
increased effect has been on the cancer cells and not on healthy cells.
Women have been using Cimicifuga during chemotherapy for years. If the
toxic effect on bone marrow was of similar hundred-fold magnitude as the
cytotoxic effect on cancer cells, someone would probably have noticed by
now.
The researchers also compared several different brands of Cimicifuga
extract. As expected the "better" companies had more striking action. Gaia
had the most effect while Nature's Answer the least action.
Although Cisplatin action and Docetaxel action were inhibited by
Cimicifuga, the inhibition was relatively small in comparison to the
combined action with Doxorubicin. Rather than powers of ten the changes are
expressed in tenths of a power.
Let me try and write this in scientific
notation. For example at 30 microM of Cisplatin, the surviving fraction
increased from about 10-1..9 to 10-1.8 when Cimicifuga was added to the
experiment.
Although this is a statistically significant difference, it may
or may not be clinically significant.
Of course all these experiments were done on cells in test tubes. Will
the same effect be seen in living animals? The implications of these early
findings are important; we can expect to see animal studies in the near
future.
Breast Cancer Research(2005) 90:233-239
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