Jane Zones, Board Member
Developing Technology to Reduce Lumpectomy Resurgeries.
Five advocates, representing BCA, Share (New York), the Sisters Network, and the Breast Cancer Support Network (formerly Y-Me), attended a meeting put together by Dune Medical Devices (dunemedical.com) to introduce a new technology that they claim assesses the presence of cancer in tissue that is removed during lumpectomy.
Estimates are that about 30% of lumpectomies require subsequent surgeries to remove additional tissue because cancerous cells are later determined by pathology to be at or close to the margin of the excised specimen.
Dune’s MarginProbe is a tool that surgeons may use to assess the presence of cancer cells at tissue margins as they operate, reducing the risk of later resurgeries. The probe, which consists of a grip having a tip with electromagnetic properties, does not touch the patient, but rather is used at the edges of the tissue after it is removed.
The probe is applied around the edges of the excised tissue, transmitting radiofrequency signals, comparing the signals to known properties of both cancerous and noncancerous tissue, and emitting a signal if cancer cells are found at the probe site.
One study of MarginProbe, published in the American Journal of Surgery in 2008, compared 300 Israeli women who had been randomized to a control group or one that employed the device during surgery. The experimental group underwent fewer than half the number of resurgeries (5.6%) than the control group (12.7%), with the volume of tissue removed and the cosmetic outcome being the same for both groups.
A second study is nearing conclusion in the United States, and the company plans to submit an application for new device approval to the Food and Drug Administration, a process that could take several years.
This meeting happened on the first day of the meeting. On the last full day of the meeting, on Saturday, Monica Morrow from Memorial Sloan Kettering, presented on the topic “Minimizing Local Control: What’s proven, what’s not. The slides from this presentation should be available at http://sabcs09.m2usa.com/sabcsdsv.html. In that presentation, Dr. Morrow cautioned against the obsessive pursuit of clear margins, largely because there is so little evidence that clear margins (larger than 1mm) make any difference in patient outcome. If Dr. Morrow is right, Dune may be barking up the wrong tree.
Bisphosphonate use and breast cancer incidence in the Women’s Health Initiative
Rowan Chlebowski, UCLA, and his colleagues analyzed data from the different component studies of the Women’s Health Initiative (WHI) and found that use of the anti-osteoporosis drugs called bisphosphonates reduced women’s risk of being diagnosed with breast cancer.
The WHI was a long-term study of tens of thousands of women over 50 that revealed the hazards of hormone replacement therapy six years ago.
Controlling for breast cancer risk factors, such as age, body mass, exercise, and hormone use, the researchers compared those who were taking bisphosphonates (most were taking Fosamax) upon entry into the study with those who were not. Of the 151,592 participants in the WHI, 2216 were oral bisphosphonate users at the start of the study.
They found that those who took bisphosphonates developed breast cancer at about 70% of the rate of those not using the drug over the course of the study. The difference was statistically significant.
Although they do not find their work conclusive, they hypothesize that the drugs have a direct inhibiting effect on breast cancer. The researchers are not encouraging women to take bisphosphonates to reduce their risk of breast cancer, though the AP press report on the study did not include this caution.
Their work was corroborated by a second study, reported by a team of Israeli researchers, who found a 29% reduction in the incidence of postmenopausal breast cancer after one year’s use of bisphosphonates by several thousand women.
We know that higher estrogen exposure over a lifetime is associated with increased breast cancer incidence, as well as with stronger bones To control for this confounding relationship, Chlebowski et al. used a measure of hip fracture risk; it was not clear to several questioners in the audience (or myself) just how this reduced the confounding relationship between these three variables.
Bisphosphonates are known to cause osteonecrosis of the jaw (bone death) a rare but debilitating and disfiguring condition. Chlebowski disclosed that he is a consultant for five major drug companies (but not for Merck, the maker of Fosamax).
Alcohol and Breast Cancer Survival
There’s quite a bit of evidence that alcohol consumption is associated with increased risk of breast cancer, but not much research on alcohol’s effects on women who have been diagnosed. Marilyn Kwan, a physician researcher at Kaiser in Oakland, reported on a project that followed women who had been diagnosed and treated for early breast cancer. Participants in the study filled out an annual questionnaire and reported on their alcohol intake, as well as health status.
Women who drank six or more grams of alcohol per day (about half a glass of wine, half a beer, or half a shot of liquor) had about a 30% increased risk of breast cancer recurrence compared to those who drank very little (under a half gram of alcohol per day) or not at all. The heavier drinkers also were at significantly greater risk of death from breast cancer, though there were no associations with risk of overall mortality.
About half of the drinking participants (half the sample identified as non-drinkers) classified themselves to be in the heavier drinking group. Although those who drank less than the six gram/day cutoff did not experience increased risk of breast cancer recurrence, the effect for the heavier drinkers was dose-related; that is, the recurrence risk grew with increasing intake of alcohol. The effect was greater for postmenopausal women and those who had ER negative tumors. This effect on ER negative tumors is somewhat puzzling, since the theory is that alcohol increases breast cancer risk when it is converted to estrogen by the liver. That would suggest a problem for women with ER positive tumors.
The researchers counsel women to limit their consumption of alcohol following a breast cancer diagnosis.