Cancer conflict with adjuvant chemotherapy

February 22, 2016

This is especially true if their tumors respond to changing levels of hormones such as estrogen, according to research published in the online journal, Breast Cancer Research.

"Developing breast cancer at a young age is very worrying in terms of survival," explained lead researcher Dr J van der Hage. "But some young women may be undergoing not only unpleasant but also unnecessary chemotherapy, which can be avoided."

Almost 10% of women diagnosed with breast cancer in Europe are under the age of forty. Two thirds of breast cancers, known as estrogen receptor positive (ER+), contain high levels of cells which contain estrogen receptors. These tumors tend to grow less aggressively than estrogen receptor negative (ER-) tumors. Young patients with breast cancer are currently advised to undergo courses of chemotherapy as well as removal of the tumor and/or entire breast. A research team of the European Organisation for Research and Treatment of Cancer (EORTC) selected patients from four EORTC-trials which were coordinated by Professor C.J.H. van de Velde from the Leiden University Medical Center, to study the effect of chemotherapy in young women. The research team found that ER+ patients, while they benefited from their chemotherapy treatment, did not survive at higher rates than ER- patients.

The difference in survival rates between the two treatment groups was just 5% (in favour of the ER- group), indicating that the chemotherapy gave no advantage. Of all the patients examined, including those who had only undergone primary treatment such as mastectomy, over 25% had died seven years after initial diagnosis.

"Adjuvant chemotherapy is a well established, but ineffective treatment in ER+ breast cancer patients aged 40 years or less . Hormone responsiveness is the key to tailoring therapy in the future fight against this disease for young women," concluded Dr van der Hage.

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???This is the first such observation that's been made, and it was made retrospectively, meaning we looked backwards instead of forwards. We are not recommending at this time that women with positive lymph nodes, for whom we would currently recommend Taxol, but who are estrogen receptor positive and HER-2 negative not take the Taxol. We think the stakes are too high,??? Hayes says.

???We've seen mortality from breast cancer dropping in recently years because we've applied these new and better therapies. But now we believe, if these results are confirmed and validated in other studies, that perhaps we could pull out half the patients in that study and save them from the toxicities and the cost of receiving a drug that might not do them any good,??? he continues.

Doctors have been able to use newer drugs, such as tamoxifen, aromatase inhibitors or Herceptin, to treat only some women with breast cancer, based on whether their tumor expresses estrogen receptor or HER-2. But this method of targeting treatment had not been possible with traditional chemotherapy. This new study suggests doctors might be able to consider estrogen receptor status and HER-2 status together to determine what treatment will be most effective, sparing some women from the toxic side effects of drugs that are not likely to be effective.

???Determining who doesn't need chemotherapy and can be spared some portion of toxic therapy is one of the biggest issues facing breast cancer today,??? says senior study author Donald Berry, Ph.D., professor and head of the Division of Quantitative Sciences at The University of Texas M. D. Anderson Cancer Center. ???In oncology, we are very good at adding therapies to a patient's regimen, but we are not as confident subtracting treatment. Hopefully, in time, we'll be able to limit therapies to those that will truly benefit from the additional regimen.???

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