Breast conserving treatment, which consists of a lumpectomy or partial mastectomy followed by radiotherapy, is an appropriate alternative to mastectomy for many early-stage breast cancer patients. Women with small, well-defined tumors are the best candidates for breast conserving therapy. Having aggressive disease, such as a triple negative tumor, does not necessarily mean that breast conserving treatment is not the best choice. However, radiation treatment is necessary after a lumpectomy to obtain a comparable result. Now a new study has reported that 20-year outcomes for women who undergo breast conserving treatment are similar to those of women who have mastectomies.

Breast conserving treatment is appropriate for small, well-defined tumors

Breast conserving treatment is most appropriate for women with small, single early stage tumors that are easy to visualize with mammography or breast MRI. Small tumors are more easy to remove completely than large tumors. Perhaps counterintuitively, the aggressiveness of the disease is not the next most important factor in deciding whether lumpectomy is appropriate. For example, triple negative tumors, which are considered aggressive, typically form discrete tumors that are relatively easy to visualize radiologically. Therefore, surgeons can be fairly confident of removing all of the tumor during surgery and obtaining clean surgical margins. However, patients with disease (such as lobular or inflammatory breast cancer) that tends to be diffuse, multifocal or difficult to detect have higher rates of mastectomy because initial breast conserving surgery is less likely to result in clean surgical margins.

Radiation treatment is an essential part of breast conserving treatment

Women who undergo lumpectomy or partial mastectomy should have radiation treatment as part of their treatment to kill any remaining tumor cells in the breast area. There is ample evidence that radiation significantly reduces the risk of locoregional recurrence, which in turn reduces the risk of distant metastasis. Some women are deciding not to have radiation treatment after lumpectomy - this is an unwise choice, based on available evidence.

Latest research finds similar long-term outcomes for lumpectomy and mastectomy

The study referenced at the beginning of this news article was designed to present 20-year follow-up results of the EORTC 10801 trial. The trial compared breast conserving therapy with mastectomy in breast cancer patients with stage I or II disease and tumor size 5 cm or smaller. The study included women with and without axillary lymph node metastases (positive lymph nodes). The EORTC 10801 trial was open for enrollment between 1980 and 1986 in eight treatment centers in the UK, the Netherlands, Belgium, and South Africa. Participants were assigned to receive either breast conserving treatment (448 women) or mastectomy (420). Breast conserving treatment consisted of lumpectomy and complete axillary node dissection, followed by breast radiotherapy plus a tumor-bed boost. The women were followed for a median of 22 years.

Compared with breast conserving treatment, mastectomy resulted in fewer local recurrences (within the same breast as the original tumor), but overall survival and time to distant metastasis were comparable. A total of 175 patients (42%) in the mastectomy group developed distant metastases during follow-up compared to 207 (46%) in the breast conserving group. There was no significant difference between the breast conserving group and mastectomy group for time to distant metastases or for time to death. The cumulative incidence of distant metastases at 20 years was 42.6% in the mastectomy group compared to 46.9% in the breast conserving group (the difference between the two groups was not statistically significant). Twenty-year overall survival was estimated to be 44.5% in the mastectomy group and 39.1% in the breast conserving group. When the analysis was performed according to age at diagnosis, no difference between the groups in time to distant metastases or overall survival was found for women diagnoses before age 50 compared to women 50 and older. The authors conclude that offering breast conserving treatment as standard care to patients with early breast cancer appears to be justified, based on similar long-term survival compared to mastectomy.