The treatment options for patients with early-stage (Stage I and II) invasive breast cancer today are breast-conservation therapy (BCT) with adjuvant radiation therapy and modified radical mastectomy (MRM) with or without breast reconstruction.

Until the late 19^th  century, there was no effective treatment for breast cancer, and most patients died within a relatively short time from uncontrolled local disease or complications of surgery. The first major advance was the development and popularization of the radical mastectomy. The operation, described by William Halsted and Willy Meyer in 1894, removed the breast and the pectoral muscles and removed lymph nodes from levels 1, 2 and 3 of the axilla.

The operation reduced the local recurrence rate from 60-70% to about 6%, establishing radical mastectomy as the standard treatment for breast cancer for three-quarters of a century. In the 1950s, Patey modified the radical mastectomy by sparing the pectoralis major muscle.

The MRM was equally effective in terms of local control and overall survival, and became the standard operation for breast cancer. Today the most common reasons that modified mastectomy is performed include patient choice, extensive local disease or an inability to receive radiation therapy.

Conservative breast surgery was introduced for small breast cancers in the 1970s. There was a gradual trend towards earlier stage at diagnosis and more appreciation of the systemic health threat breast cancers can pose. The ogical extension of both was to reduce the magnitude of the local surgery and attempt to preserve the organ.

Throughout the 1970s and 1980s, large numbers of patients participated n trials in the USA and Europe to evaluate the safety and efficacy of breast-conservation therapy. Participants were randomized to either wide excision of the tumor and radiation therapy or mastectomy. These studies demonstrated that BCT was as safe as mastectomy in selected patients but was preferred because it is less disfiguring. The first trial reported was from the National Tumor Institute in Milan, Italy, by Veronesi. 

Their trial compared radical mastectomy with ‘quadrantectomy’ (excision of one-quarter of the breast) followed by radiation therapy (QUART) for clinically T1N0 breast cancers. There was no difference in survival and little difference in local recurrence rates between the two treatment approaches.

The major US trial was the NSABP-B06 trial, which ran from 1976-1984 and was first reported in 1985 by Fisher.  Over 1,800 patients with tumors up to 4 cm in size were randomized to total mastectomy or tumorectomy with or without adjuvant radiation therapy. Negative histologic margins were required, and any patient with positive margins went on to total mastectomy.

The incidence of recurrence within the breast at 5 years was 8% in the tumorectomy -and -radiation -therapy group, and 28% in the tumorectomy-alone arm (10% and 39%, respectively, at 8 years). There was no significant difference in overall or distant disease-free survival between the arms of the trial. As a result of these and further trials, BCT is now possible in about two-thirds of patients presenting with breast cancer.