Lumpectomy/Mastectomy Equivalent in Early Breast Cancer

NEW ORLEANS—Eighteen-year results from a pivotal trial comparing lumpectomy with mastectomy have demonstrated maintenance of efficacy for the breast-sparing treatment. Matthew Poggi, MD, of the Radiation Oncology Branch of the National Cancer Institute, updated the study results at the American Society for Therapeutic Radiology and Oncology (abstract 91).

In the original study, 247 patients with stage I and II breast cancer were randomly assigned to undergo either modified radical mastectomy or lumpec-tomy plus level 1-3 axillary dissection and radiation therapy (4,500 to 5,040 cGy) for 5 to 5.5 weeks. A boost of 1,500 to 2,000 cGy was given to all patients, and in some patients the internal mammary or supraclavicular lymph nodes were treated. Node-positive patients received chemotherapy and sometimes tamoxifen (Nolvadex). Negative surgical margins in the lumpectomy group were not required.

Final analysis was done on 116 patients in the mastectomy arm and 121 women in the breast-conservation arm. At a median follow-up of 18.4 years, overall survival was 58% for mastectomy patients and 54% for patients receiving lumpectomy plus radiation. Disease-free survival was 67% and 63%, respectively, after recurrences successfully salvaged by mastectomy were censored from the analysis. Distant disease-free survival was 69% for mastectomy vs 68% for breast conservation.

None of these differences were significant, Dr. Poggi reported. Over time, the percentage of surviving patients declined similarly between the two arms, he said.

In the subset of node-positive women, median follow-up is somewhat shorter; however, the outcome was consistent with the findings for the whole group. There was no significant difference in survival, with 46% of mastectomy patients and 48% of breast-conservation patients alive at 15 years. For disease-free survival, however, the absolute percentages were higher for the breast-conservation group: 45% for mastectomy and 54% for breast conservation at 15 years, Dr. Poggi reported.

The investigators are currently analyzing the failure rates and patterns, and what has emerged so far is an in-breast tumor rate—either recurrence or new primary tumors—that is higher than in previous studies. Dr. Poggi attributed this to the fact that negative surgical margins were not required for lumpectomy, and to the likelihood that more events will occur with longer follow-up.

He said that 21 of the 27 new or recurring ipsilateral breast tumors in the breast-conservation group were successfully treated; three patients also had distant failure, and four had salvage mastectomy that did not control the local disease, he said. "There appears to be no detectable difference in two very important clinical endpoints, overall survival and disease-free survival, for early breast cancer patients treated with either mastectomy or breast-conservation surgery plus radiation, after nearly 20 years of follow-up," Dr. Poggi concluded. "These findings contribute to the growing body of research that suggests that lumpectomy can be just as effective as mastectomy."

Recently, updates of two other large, randomized trials of breast conservation plus radiotherapy vs mastectomy found similar results, with no significant differences in overall or disease-free survival with 20-year follow-up. The studies, from the National Surgical Adjuvant Breast and Bowel Project (NSABP) and from Milan, Italy, were both reported in the New England Journal of Medicine (October 17, 2002).