Thursday, February 17, 2005
By Jeanie Lerche Davis
A 76-gene “signature” has been linked with breast cancer tumors that are more
likely to spread to other organs. The new finding could mean fewer women will
get chemotherapy when they don’t need it, researchers say. However, others say
the puzzle is not yet solved.
Currently, there are no reliable tools to predict which breast cancer patients
are most likely to have cancer recurrences, writes researcher Yixin Wang, PhD,
with Veridex LLC in San Diego. Wang’s paper appears in the latest issue of The
Lancet.
Upwards of 70 percent of breast cancer patients whose cancer hasn’t spread to
lymph nodes are successfully treated with surgery and radiation therapy, Wang
writes. Yet treatment guidelines for these patients recommend that 85 to 90
percent also get chemotherapy to help eliminate cancer cells that might be in
the body. Because there is no reliable way to determine which early breast
cancer (cancer that has not spread to other organs) will spread, many women at
this stage of cancer will receive chemotherapy even though it may be
unnecessary.
If they can more accurately identify patients with less risk of recurrence,
doctors can avoid prescribing unnecessary treatment or choose less-aggressive
therapies for these patients.
Wang’s study involved 286 patients whose breast cancers were localized only to
the breast (lymph node-negative). None of the patients got chemotherapy after
surgery. All the women’s tumors were given genetic testing.
The women were followed for an average of eight years. During that time
one-third of the women developed cancer recurrence.
The study showed that a set of 76 genes (gene signature) could accurately
predict women at high risk of recurrence.
The gene signature was highly informative in predicting which women would have a
recurrence of cancer within five years. Women with the gene signature had an
almost fivefold risk of developing cancer recurrence even after taking into
account other factors that traditionally predict risk of recurrence, including
tumor size, a woman's age, and estrogen receptor status of the tumor.
The gene signature “could provide a powerful tool to identify those patients at
low risk, preventing overtreatment in substantial numbers of patients,” writes
Wang.
Wang’s finding “is not by itself sufficient” in identifying which women might
get breast cancer recurrences, writes Tor-Kristian Jenssen, a tumor biologist
with PubGene AS in Vinderen, Norway, in an accompanying commentary.
Several large studies have identified signature gene patterns to predict whether
a patient’s breast cancer will spread or not. However, each group of researchers
came up with vastly different gene patterns.
“We are left with obvious questions of which to trust and why they differ,”
writes Jenssen. “The signature is there, but it is still necessary to read the
fine print.”
Source :
http://www.foxnews.com/story/0,2933,147988,00.html
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