Research findings reported in the Oct. 17 New England Journal of Medicine (Vol. 347, No. 16: 1227-1232; 1233-1241; 1270-1271) should put to rest the question of whether women will do worse if they select conservative treatment of breast cancer.

Researchers have confirmed that women will do just as well with breast-conserving therapy as they would if they had more radical surgery, assuming the tumor is not more than about 5 cm, or about 2 inches, in diameter.

One study was performed in Italy. The other study included research conducted in the US, Canada, and Australia. Both studies have been underway for more than 20 years.

The first report, by Umberto Veronesi, MD, of the European Institute of Oncology in Milan, Italy, and colleagues, enrolled 701 patients from 1973 until May 1980. About half of the women had traditional surgery — the generally accepted radical mastectomy. The other half of the women had the new, controversial breast-conserving surgery.

In this study, the women's cancers were all 2 cm or less in diameter.

The women who had a radical mastectomy also had the lymph nodes under the arm (axilla) removed at surgery.

In the breast-conserving group, women had a quadrantectomy, where their breast cancer and a large portion of normal tissue around the tumor was removed from the breast. This procedure can be extensive and not unlike a simple mastectomy. The women also underwent lymph node removal, followed by radiation treatment to the breast.

Early in the trial, if women had cancer in their lymph nodes they also received additional radiation to areas adjacent to the breast. However, this was only done from 1973 to 1975.

From 1976 forward, if any of the women in either group had cancer in the lymph nodes they received adjuvant chemotherapy.

The women who had conservative surgery had more breast cancer recurrences in the breast — about one in 11 women. This was compared to about one in 40 women who had a radical mastectomy, where the breast was removed as part of the surgery (in these women, the cancer recurred in the chest wall or in the scar from the surgery).

Despite the larger number of recurrences of cancer in the women with lumpectomy, the researchers found no differences between the two groups when they looked at the number of breast cancers that occurred in the opposite breast, the number of recurrences in the body in places away from the breast, and, most important, the rate of death from all causes.

"Our results show that the long-term survival of women with early breast cancer who were treated with breast-conserving surgery and postoperative radiotherapy to [the breast involved with the cancer] was virtually identical to the rate among women who underwent radical mastectomy," wrote the authors.

"These results should dispel any lingering doubts about the safety and efficacy of breast-conserving surgery as a treatment for breast cancer," they wrote.

They also concluded that the radiation used to treat the breast with cancer did not harm the other breast.

The second study was part of the National Surgical Adjuvant Breast and Bowel Project (NSABP). Bernard Fisher, MD, past chair of the NSABP and Distinguished Service Professor at the University of Pittsburgh, and colleagues reported findings from this study.

Fisher looked at 1,851 women with breast cancers that were less than 4 cm in diameter who were enrolled in the study from August 1976 until January 1984.

These women were treated with either a lumpectomy (removal of the cancer from the breast, with at least a thin margin of normal tissue) or a total mastectomy. All of the women had the lymph nodes under the arm removed. Half the women who had a lumpectomy received radiation therapy following surgery. The others did not receive any radiation.

Any woman with cancer in the lymph nodes received adjuvant chemotherapy.

Women who had a lumpectomy without radiation in this report had about a four in 10 chance of having the breast cancer recur in the breast. The women with radiation following the lumpectomy had about a one in seven chance of a similar recurrence.

More recent trials have shown a recurrence rate in the breast after lumpectomy of 6%, according to the article. Women who had a recurrence of cancer in the breast could still be effectively treated with a lumpectomy or mastectomy at the time of recurrence.

All three groups had the same rate of survival without evidence of disease (called disease-free survival). Overall survival was also the same for the three groups.

Most of the first recurrences of cancer were within five years of surgery (69%), according to the report. However, some recurrences were found after 10 years of follow-up. One-third of the breast cancers that occurred in the opposite breast were found more than 10 years after surgery, underlining the need for careful, long-term follow-up of these women.

"After 20 years of follow-up, we found no significant difference in overall survival among women who underwent mastectomy and those who underwent lumpectomy with or without postoperative breast irradiation," the authors wrote.

In an editorial in the same issue of the journal, Monica Morrow, MD, a surgical oncology professor at Northwestern University Feinberg School of Medicine in Chicago wrote, "The failure to observe a survival advantage of mastectomy after 20 years should convince even the most determined skeptics that mastectomy is not superior to breast conservation for the treatment of breast cancer."

Morrow emphasized that some of the newer breast imaging methods, such as ultrasound and MRI, may find other small cancers in the breast before surgery is done. However, this should not discourage women from undergoing conservative lumpectomy with radiation after surgery.

Fisher agrees and calls this one of the "paradoxes of our time." With improved imaging techniques, doctors are finding other small areas of cancer in the breast and lymph nodes that weren't found before with older tests.

"Surgeons are asking, 'How can we leave this behind?'" he said. And that may lead to more mastectomies, which he still believes are not needed in this situation.

Morrow said, "Subjecting women to mastectomy because we now have an imaging technique that is sensitive enough to detect [very small areas of cancer] is not a step forward."

Morrow said the bigger problem is the fact that "many women today are not offered the option of breast-conserving surgery."

She saved her strongest comment for the editorial's conclusion.

"If we do not apply what we have learned from the pioneering work of Fisher and Veronesi and their colleagues to the treatment of women with breast cancer we see today, we will have made little or no progress over the past 20 years in the search for a rational approach to the local treatment of breast cancer," Morrow said.

"It is time to declare the case against breast conserving therapy closed and focus our efforts on new strategies for the prevention and cure of breast cancer," she concluded.

Fisher said, "This study continues the theme of our prior report in August 2002. These studies broke the shackles of Halsted's concept and proved that if you did less than a radical mastectomy, cataclysmic things wouldn't happen to women with breast cancer.

"This study shows unequivocally that you can do breast-preserving surgery without dire consequences," he said.

Fisher has been a leading advocate of conservative breast surgery for more than 30 years. Now, he said, "There is rarely a situation where you shouldn't be able to preserve the breast. Tumor size is not as critical as we thought."

The most important difference, he noted, is that the cancers were considerably smaller in the Italian study compared to the NSABP study. According to Fisher, with time and new approaches, surgeons have learned they can safely perform lumpectomies on women with breast cancers as large as 5 cm.

There are other important factors to consider when looking at the NSABP study, he said. "This is a historic study that treated women in the 1970's and 1980's. Today, the cancers are smaller, we detect them earlier, and we use systemic therapy for many of them."