Mar. 31, 1997 By Victoria White
GAINESVILLE, Fla.---For the past decade, University of Florida radiation oncologists have differed with many breast cancer specialists regarding treatment for women who have undergone mastectomies. But recent large-scale studies in Denmark and Canada show UF's approach may be linked to better long-term survival rates.
At issue: How extensive should radiation therapy after mastectomy be to prevent cancer from recurring and spreading?
The question is critical, since the spread of cancer cells through the body is largely to blame for the more than 40,000 annual breast cancer deaths in the United States.
Physicians at the UF Shands Cancer Center have assumed that all sites in the breast and nearby lymph tissue where cancer cells might lurk must be radiated.
They reasoned this approach might reduce the risk of cancer cells spreading to distant areas, such as the brain or liver. The risk of death, therefore, also would be lowered. But many other physicians use radiation only in easy-to-target areas and where cancer commonly reappears.
"Research done in the 1960s and 1970s seemed to show that cancer cells spread despite local and regional radiation," said Dr. Nancy Mendenhall, professor and chairwoman of the department of radiation oncology at UF's College of Medicine .
"Many physicians thought this meant that cancer spread always occurs early and thus cannot be affected by subsequent radiation. Consequently, many radiation oncologists used radiation only for the limited purpose of controlling the cancer right in the breast region," Mendenhall said. UF physicians, however, "thought the radiation in those old clinical trials may not have covered all the sites in the breast and lymphatic region where cancer cells might be present," said Mendenhall. "If all the sites at risk were not irradiated, cancer cells could have continued to thrive and spread throughout the body.
"Those old trials were done before we had CT scanning available. Such computerized X-ray imaging documents more disease in the breast region than physical examinations and can help us target the radiation better. For these reasons, we have always attempted to treat all areas at risk."
The new data reported by the Danish Breast Cancer Cooperative Group and the British Columbia Cancer Agency in Canada strongly back UF's interpretation and treatment philosophy. The studies, which tracked thousands of patients for more than eight years, showed cancer spread sometimes can be curtailed with thorough local and regional radiation. Such an approach improves the survival rates of breast cancer patients between 7 and 10 percent.
"Unquestionably we have been in the minority with our position on radiation treatment," Mendenhall said. "But I think we're going to see a change in attitude among other physicians based on these studies."
Mendenhall plans to publish UF's patient survival data this summer in the 2nd edition of the book, The Breast: Comprehensive Management of Benign and Malignant Diseases. The book's editors are Dr. Kirby Bland, former associate chairman of UF's department of surgery, and Dr. Edward M. Copeland III, chairman of surgery and interim dean of the College of Medicine.
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