NEW YORK (Reuters Life!) - Racial disparity in death rates between African American and other women with breast cancer may be due in part to surgery which may encourage the growth of the tumour, an international team of researchers said.
African American women are often diagnosed with breast cancer at an earlier age and have a higher risk of dying from the illness. The average age when their disease is detected is 46, compared to 57 years old for white women.
Earlier research has suggested that women who have surgery for breast cancer before going through the menopause, which usually occurs around the age of 50, have a higher relapse rate.
Scientists in the United States, Britain and Italy who studied databases on early diagnosis, death rates, and racial disparity believe surgery could be associated with the higher risk of dying from the illness.
"Surgery to remove a primary tumour induces the formation of new blood vessels - known as angiogenesis. In pre-menopausal women who have high levels of oestrogen and other hormones, this may encourage the growth of the tumour," said Dr. Isaac Gukas, of the University of East Anglia in England.
"Many factors might be acting together. We think that new blood vessel formation in response to surgery might be one of the significant factors contributing to early death following breast cancer," he added in a telephone interview.
Gukas, Dr. Michael Retsky of the Children's Hospital in Boston, Massachusetts and Romano Demicheli, of the Istituto Nazionale Tumori in Milan and William Hrushesky of the University of South Carolina reported the hypothesis in The International Journal of Surgery.
"This is a hypothesis based on what we have looked at in this previously published data," said Gukas.
The scientists believe it could help to explain the racial disparity but more studies are needed to confirm it.
"Now we need further research to confirm these observations before we explore any necessary changes in practice," said Gukas.
If the hypothesis is confirmed, the researchers said it might be better to give chemotherapy and angiogenesis inhibitors to women before surgery to improve their outcome.
Breast cancer is the most common cancer in women, with more than a million cases detected worldwide each year, according to the International Agency for Research on Cancer (IARC) in Lyon, France.
The illness is treated with surgery and radiotherapy, chemotherapy and hormone treatment, or a combination of them, depending on the cancer and stage of the illness.
Factors which can increase a woman's risk of breast cancer include having a mother or close relative with the disease, inherited mutations in the BRCA1 or BRCA2 genes, an early puberty, late menopause and not having any children.
This article is an example of research that could possibly change the way breast cancer is treated. The results suggest that waiting to have surgery until after chemotherapy and targeted therapy medicine might benefit some women with breast cancer. But we just don't know enough right now to say with confidence that this approach is better than what is typically done today: surgery first, then other therapies.
It's been known for a while that African American women tend to be diagnosed with breast cancer at an earlier (often premenopausal) age than white women. African American women are also more likely to die from breast cancer than white women. In the study reviewed here, the researchers were trying to understand why being diagnosed before menopause would increase a woman's risk of dying from breast cancer. The researchers looked to see if surgery played a role. Surgery is typically the first step in treating breast cancer.
The researchers suggest that cutting and removing a breast cancer may actually stimulate the growth of new blood vessels where the cancer was removed. Those new blood vessels may make it easier for another cancer to grow.
How is this related to African American women who are diagnosed with breast cancer before menopause? Younger women who are premenopausal usually have higher estrogen levels. The researchers think that the new blood vessel growth after surgery, combined with higher estrogen levels might work together to stimulate a cancer to come back and grow. This might explain why premenopausal African American women have a higher risk of dying from breast cancer.
At this point, it's just a hypothesis, which means that the researchers think it might be true but won't know for sure until more research is done.
Other research studies are evaluating targeted therapies to treat some breast cancers. One targeted therapy works by stopping new blood vessels from developing. Avastin (chemical name: bevacizumab) is an example of this type of targeted therapy. Avastin is approved by the U.S. Food and Drug Administration to treat advanced colon cancer. Early research results show that Avastin might help treat advanced breast cancer.
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