Progress in Predicting Invasive Breast Cancer
Researchers Identify Biomarkers That May Help Decide Who Will Need Aggressive Treatment
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.
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.