To spare some women treatment that isn't necessary, experts—and the NIH panel—say medicine must figure out how to stratify women by risk, through the genetic fingerprint of the tumor, proteins it expresses, or other methods. If cells with a specific gene signature, for example, were unlikely to become invasive disease, radiation could be skipped, says Allegra. But, he says, "it's hard to imagine not doing any surgery."
But researchers at the University of California-San Francisco say that may not be so far out. They see DCIS as only a part of a larger problem of breast cancer overtreatment. One of them, Laura Esserman, director of the Carol Franc Buck Cancer center and professor of surgery and radiology, coauthored an attention-getting analysis that appears in this week's Journal of the American Medical Association and calls for a rethinking of screening for both breast and prostate cancers. The argument: Since mammography has become commonplace, many more early cancers are being found, but the number of cases caught at more advanced stages hasn't declined by a similar amount, which you'd expect if a screening test were identifying early cases before they progress. That suggests that while screening does find breast cancers early, some of those may never have needed to be treated, while some cases of invasive cancers are evading detection by screening. So better research, again, is necessary to figure out which patients have high-risk disease and whether low-risk cases can be treated less aggressively.
Lacking that information, one immediate solution is to cut back on screening in women over the age of 70 or 75, says Esserman, since there are no data that mammography improves their survival. She also suggests that low-risk calcifications not be biopsied. And, she says, it's crucial to develop alternative methods of preventing invasive breast cancer. For example, she is studying whether statins given before surgery to women with high-grade DCIS might produce beneficial changes in the tumor and reduce the chance that invasive cancer would occur.
Shelley Hwang, chief of breast surgery at the UCSF Breast Care Center, is studying whether hormonal therapies such as tamoxifen and aromatase inhibitors might ameliorate DCIS in women whose breast cells are estrogen-receptor positive. One recently completed study of more than 60 women involved three months of hormonal therapy before surgery. MRIs from the beginning and the end of the study period showed smaller tumors, and under a microscope, the cells looked less malignant. Next up is a larger study that will treat women for six months before surgery. The eventual goal is to identify those women who do not need surgery at all for DCIS.