New techniques for detecting breast cancer may be leading more women to have their entire breast removed, researchers said Thursday. The study found that at the Mayo Clinic in Rochester, Minn., the percentage of women opting for mastectomy rather than lumpectomy began rising sharply after 2003, in reversal of a previously downward trend. It is not clear that the experience at the clinic reflects that of the entire nation, though there is some evidence pointing to a wider tendency. And one possible explanation is that magnetic resonance imaging, which is relatively new, detects more possibly cancerous growths than does mammography. That could be causing patients and doctors to conclude that a lumpectomy, which removes just the part of the breast containing the primary tumor, may not be sufficient. The study will be presented in Chicago at the annual meeting of the American Society of Clinical Oncology, which begins May 30, but was discussed in a telephone news conference on Thursday. The society made available on Thursday night the abstracts for most studies to be presented at the conference. This is the first year it has released such information in advance. In the past, it usually sent abstracts in advance only to its members. But that allowed cancer doctors, or Wall Street investors with access to those doctors, to trade on information about the results of clinical trials before the data became public. Among the other studies to be presented at the conference is one that found that patients with newly diagnosed breast cancer who had low levels of vitamin D had a much greater probability of dying or experiencing a spread of the cancer than patients with sufficient levels of the vitamin. But the research was not designed to establish that vitamin D deficiency was the cause of the worse prognosis. So Dr. Pamela J. Goodwin of the University of Toronto, an author of the study, said it would be premature to recommend that breast cancer patients take megadoses of vitamin D. Dr. Julie R. Gralow, a breast cancer specialist at the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle, concurred. “We have no idea whether correcting a vitamin D deficiency will alter these outcomes,” said Dr. Gralow, chairwoman of the oncology society's communications committee. The study followed 512 women treated for early-stage breast cancer in Toronto from 1989 to 1995, and tracked them through 2007. Those with vitamin D levels so low at the time of diagnosis as to be deemed deficient had nearly twice the risk of the cancer's recurring or spreading as those with sufficient levels, and a 73 percent greater risk of dying. Only 24 percent of the women had sufficient levels at the time of diagnosis. The mastectomy study followed more than 5,400 women who had surgery at the Mayo Clinic from 1997 to 2006. The share of those choosing mastectomy instead of lumpectomy fell to 30 percent in 2003 from 45 percent in 1997, then turned and rose to 43 percent in 2006. Dr. Matthew P. Goetz of the Mayo Clinic, an author of the study, said he suspected that one reason for the rise in mastectomies was the increasing use of M.R.I. scans starting around 2003. Among women having breast surgery from 2003 to 2006, 52 percent of those who had an M.R.I. before the operation elected mastectomy, compared with 38 percent of the women who did not have an M.R.I., Dr. Goetz said. But the mastectomy rate went up after 2003 even among women who had not had an M.R.I. scan. So other factors may be behind the increase as well, Dr. Goetz said, including improved techniques for breast reconstruction and the use of genetic testing to identify women likely to have a recurrence. With mastectomy a much more radical procedure than lumpectomy, doctors say, it would be a concern if women were undergoing it needlessly. Studies have shown that women who have mastectomies do not live longer than those who get a lumpectomy followed by radiation to treat any tiny tumors remaining. Those who get mastectomies do have a lower chance of cancer's recurring in the little that remains of the breast, however. And they usually do not require radiation treatment. A study last year found an increase in women choosing to have their healthy breast surgically removed with their affected breast. Dr. Gralow, of the University of Washington, said she had noticed an increase in the mastectomy rate in her own practice as well. She said this was mainly among younger, well educated Caucasian women who wanted to avoid the frequent mammograms and biopsies needed to detect a possible recurrence. “They really understand they are not impacting their overall survival,” she said. “They are impacting their local recurrence.” - NYT __
