Frank A. Vicini, MD, and colleagues at William Beaumont Hospital in Royal Oak, Mich., analyzed long-term results of 146 patients treated with lumpectomy followed by radiation between 1980 and 1993 for ductal carcinoma in situ (DCIS), a noninvasive cancer of the breast?s milk ducts. Their study was published in the Journal of Clinical Oncology (Vol. 18, No. 2).

The researchers found that at an average follow-up time of about seven years, the cancer had come back in 26 percent of women 45 or younger, but in only nine percent of women older than 45.

The researchers found women younger than 45 typically had less tissue removed, even though their tumors usually were as large or larger than those of older women. Younger women who had larger lumpectomies were no more likely than older women to have the cancer return. "The study shows the smaller volume of tissue typically removed in younger women is most likely what accounts for their higher rates of recurrence," Dr. Vicini said.

Younger women may need more tissue taken out when they have a lumpectomy, said Kimberly J. Van Zee, MD, of Memorial Sloan-Kettering Cancer Center in New York, author of a previous study on the same topic with similar findings. "Their breasts have more ducts, and more connections between ducts so there?s a greater chance of the DCIS being spread out," she said.

To increase the chances of getting all the cancer cells out, surgeons remove some cancer-free tissue ? called the margin ? around the cancer. As the size of the margin goes up, the chances of the cancer returning go down. "There?s a dramatically lower recurrence rate with a 10 millimeter margin ? about a half-inch ? compared to a one or two millimeter margin," said Dr. Van Zee.

"But as margin size goes up, more breast tissue is removed, so women, and younger women especially, try to balance a desire for a good cosmetic result with a desire for a good medical result," she added. "These studies show doctors and patients may want to be especially careful in constructing that balance."

LaMar McGinnis, MD, medical consultant to the American Cancer Society (ACS), agreed. "It is very important to get a good, wide, clear [cancer-free] margin to avoid recurrence. A significant percentage of recurrences are invasive breast cancer."

Lumpectomy may not be the best treatment for every patient with DCIS, Dr. McGinnis added. "If a patient has a large volume of DCIS and a small breast, it may not be possible to do a lumpectomy that?s not disfiguring. It may be better for that patient to have a mastectomy and a reconstruction."

In addition, patients who choose a lumpectomy should not push their surgeon too much for a perfect cosmetic result, he said.

"There?s no question that lumpectomy plus radiation is equal to mastectomy in treatment of DCIS, provided you follow the rules," concluded Dr. McGinnis. "You must take out enough tissue to get good margins, you must follow up with radiation in most cases, and consider using tamoxifen to reduce the risk of recurrence and development of new cancers. That?s how you get the best results."