Progress in Predicting Invasive Breast Cancer
Researchers Identify Biomarkers That May Help Decide Who Will Need Aggressive Treatment
Predicting Invasive Breast Tumors continued...
The study showed that women who express high levels of three biomarkers -- p16, cyclooxygenase-2, and Ki67 -- also had a substantially higher-than-average eight-year risk of developing invasive cancer (27.3%).
The researchers stratified all 1,162 women into four risk groups. A total of 17.3% were in the lowest-risk group, with only a 4.1% chance of developing invasive cancer at eight years; 26.8% were in the next lowest risk group, with a 6.9 chance of developing invasive cancer at eight years. If the findings are validated, it is these two groups that could forgo treatment other than lumpectomy and active surveillance, Kerlikowske says.
A total of 27.6% of the women were in the high-risk group, with a nearly 20% chance of developing invasive cancer at eight years. These are the women who need more aggressive therapy with radiation and perhaps hormone therapy, she says.
Factors associated with a higher risk of having a subsequent ductal carcinoma in situ included having no cancer cells remain within 1 millimeter of the area from which the lump was removed and different combinations of biomarkers.
Still, many questions remain.
For starters, about half of women who developed invasive cancer in the study didn't have the three biomarkers or DCIS diagnosed from a lump, so the researchers have to figure out what other factors are at play, Kerlikowske says.
Also, the approach has not been shown to actually extend lives.
Additionally, the study involved women who had undergone lumpectomy alone, which is no longer the standard of care, says Ramona Swaby, MD, a breast cancer specialist at Fox Chase Cancer Center in Philadelphia.
Recurrence rates are lower in women who also get radiation and if needed, hormone therapy, so it's important to see if the findings hold up in such women, she tells WebMD.
Craig Allred, MD, of Washington University School of Medicine in St. Louis, also calls for further study in an editorial accompanying the study. Still, "if validated, the results could optimize current therapy in certain settings: [withholding] radiation from women with low-risk DCIS, for example," he writes.
Several companies have expressed interest in helping to further develop and eventually market any tissue biomarker test, which will also need FDA approval, according to Kerlikowske.
Since it utilizes the same method and can be done at the same time doctors determine a tumor's hormone-receptor status, she doubts it will cost more than a few hundred dollars.
Funding for the research was provided by the National Cancer Institute and the California Breast Cancer Research Program.