Many women with two or three breast tumors can get by with lumpectomy surgery instead of having their whole breast removed, a new study suggests.

In recent years, more patients with multiple tumors have been identified, a result of more sensitive imaging techniques that can reveal tiny, once-hidden cancers. That means more patients are being diagnosed with multiple cancer sites in the same breast.

In the past, doctors would say these women needed mastectomies. Researchers wanted to know: Was this dogma still true?

They followed nearly 200 women with two or three tumors in one breast who had lumpectomies followed by radiation. The patients ranged in age from 40 to 87. To take part in the study, their tumors had to be less than 5 centimeters and separated by 2 to 3 centimeters of normal breast tissue.

After five years, just 3% saw cancer come back, similar to rates from previous lumpectomy studies in patients with only one tumor. The study, supported by the National Institutes of Health, was being discussed Friday at the San Antonio Breast Cancer Symposium.

"This study caught my attention very quickly," said Dr. John Kiluk, a surgeon at Moffitt Cancer Center in Tampa, Florida, who was not involved in the research. "It is definitely a step forward for our field."

Lumpectomy's advantages include quicker recovery and, often, better cosmetic results.

No surgery guidelines existed for these patients, but some doctors already were offering lumpectomy as a choice, said Dr. Judy Boughey of Mayo Clinic, who led the research.

"This will make them more comfortable with that approach," Boughey said. "And I think it will also make patients ask their surgeon, 'OK, I have two sites of disease. Do I have to have a mastectomy? Or can you give me breast conservation?'"

The study did not randomly assign patients to lumpectomy or mastectomy. That would have yielded better data, but it would be nearly impossible to find women willing to be randomly assigned, Boughey said, making such an experiment impractical.

In the study, the women who had an MRI before surgery did the best, suggesting MRI scans may help surgeons be more thorough at removing cancer.

The study is part of a larger research movement aimed at avoiding overtreatment and unnecessary side effects by "right-sizing" cancer care, Boughey said.

"Do we have to throw the kitchen sink at everyone?" she asked. "Which patients need every single option that we have available and which will do just as well without having the kitchen sink thrown at them? Every single treatment has some kind of side effects."

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--Carla K. Johnson