April 28, 2010 -- Doctors are a step closer to being able to predict which women with noninvasive breast tumors will go on to develop invasive breast cancer -- and therefore whether or not they need more aggressive treatment.
Researchers studied nearly 1,200 women with ductal carcinoma in situ (DCIS), a noninvasive and very early form of breast cancer confined to the milk ducts. They found that a combination of three tissue biomarkers was associated with a high risk of developing an invasive breast cancer with the potential to spread eight years later.
Also, DCIS that was diagnosed from a breast lump was linked to a greater risk of subsequent invasive cancer than DCIS that was diagnosed by mammography.
There's still a long way to go before the personalized approach to treatment is ready for prime time.
"But the study gets us closer to our goal of separating women with DCIS into risk groups, so as to avoid overtreatment of women with low-risk breast lesions and undertreatment of women with high-risk lesions," study researcher Karla Kerlikowske, MD, of University of California, San Francisco, tells WebMD.
The study was published online by the Journal of the National Cancer Institute.
Currently, overtreatment of DCIS, which will be diagnosed in over 47,000 women this year, is the big problem, according to Kerlikowske.
"Since there's currently no way to predict which women with DCIS will go on to develop invasive cancer, almost all are offered radiation after the lump is removed [lumpectomy] or mastectomy and sometimes hormone therapy. But our results suggest as many as 44% of women with DCIS may not require any treatment other than removal of the lump and can instead rely on active surveillance, or close monitoring," Kerlikowske says.
The close monitoring offers these women a safety net, she says. "If a tumor comes back, we can always give radiation then."
Radiation therapy not only carries a risk of side effects such as nausea, vomiting, and fatigue but also precludes irradiating the same area of the breast a second time, Kerlikowske says. "So you want to save it for when it is really needed," she says.
Predicting Invasive Breast Tumors
The study involved 1,162 women aged 40 and older who were diagnosed with DCIS and treated with lumpectomy alone between 1983 and 1994.
Overall, their eight-year risks of developing a subsequent DCIS or a subsequent invasive cancer were 11.6% and 11.1%, respectively.
When the researchers looked at women whose DCIS was diagnosed by feeling a lump, the eight-year risk of subsequent invasive cancer was substantially higher than average, 17.8%.
Then they looked at different combinations of biomarkers using tissue that had been stored for 329 of the women when they were first diagnosed with DCIS. These biomarkers include estrogen receptor, progesterone receptor, Ki67 antigen, p53, p16, epidermal growth factor receptor-2, and cyclooxygenase-2.