Research Notes
Breast-conserving surgery as good as mastectomy after 20 years
It comes as no surprise to Dana-Farber doctors, but is reassuring nevertheless. Two recent studies have shown that women who had lumpectomies or partial mastectomies for early breast cancer were just as likely to be alive 20 years later as those who had their entire breast removed.
Back in the early 1970s, when researchers launched the studies to compare the two types of treatment, many cancer specialists felt that a radical mastectomy was the safest method of eradicating the cancer cells. Others, however, argued that the less-disfiguring surgeries, leaving the rest of the breast and the underlying muscles intact, was just as effective.
One of the studies reported in the New England Journal of Medicine last October was from the European Institute of Oncology in Milan, Italy, where researchers had followed 701 breast cancer patients since 1973. They compared the effectiveness of radical mastectomy with quadrantectomy, in which about one-fourth of the breast is removed. The other study was carried out by the University of Pittsburgh and showed that in a group of 1,800 patients, survival rates 20 years later were the same between patients who underwent removal just of the cancerous lump and those who had radical mastectomies.
Lab experiment reveals details of early breast cancer
The smallest unit of normal breast tissue is a cluster of cells, called an acinus, with a hollow center, or lumen, where milk is secreted. Much of the breast tissue is made up of thousands of these acini. In the early stages of breast cancer, the lumens become clogged with cells proliferating out of control. New findings in the laboratory of cell biologist Joan Brugge, PhD, a member of the executive committee of the Women's Cancers Program, show that cancer cells must overcome a protective cell-death process — known as apoptosis — before they can accumulate in these hollow spaces on their way to tumor formation.
Apoptosis is a key part of the development of the normal acini. Also known as "programmed cell death," apoptosis causes normal cells to self-destruct after a certain time, so they don't litter the lumen and the acinus maintains its proper structure. But the cancer cells can overcome apoptosis and fill up the lumen if they also get a second signal that triggers proliferation of the cells. The two signals must act in combination for the cancer cells to fill the lumen.
Dr. Brugge, in an article in the Oct. 4, 2002, issue of the journal Cell, said her findings were made possible by creating three-dimensional cell clusters in the laboratory that resemble acini. Into these clusters, she and her colleagues introduced the gene HER2, which can be a cancer-causing gene. This gene sent the two signals necessary for the breast cells to fill up the hollow clusters and start the cancer process.
"Our studies provide the first evidence that circumventing apoptosis is an important barrier for cancer genes to overcome in order to populate the lumen of the glandular structures," wrote Dr. Brugge, whose laboratory is in the Harvard Medical School. Dr. Brugge is part of a large team assembled by Myles Brown, MD, to study the poorly-understood ER-negative breast cancer, which is not fueled by estrogen, as the majority of breastcancers are (see: A new target in breast cancer).
