Over the past 50 years, the National Surgical Adjuvant Breast and Bowel Project (NSABP) has made significant contributions in reducing the extent of surgical resection and in improving the outcome of patients with early-stage breast cancer through the conduct of large, randomized clinical trials evaluating various aspects of local and systemic therapy. Some of these trials have been instrumental in establishing new standards of care in the locoregional and adjuvant systemic therapy for these patients. The rationale, design, and updated results from those pivotal trials are reviewed in this chapter. In addition, the design and rationale for newer trials put forth by the NSABP and other major cooperative groups in an attempt to refine several aspects of adjuvant therapy and introduce new promising drugs are also reviewed. Finally, current and future research directions of the NSABP in the context of other developments in the surgical and adjuvant breast cancer therapy are discussed.
Trials Evaluating Less Radical Breast Surgery in Patients with Invasive Carcinoma
The National Surgical Adjuvant Breast and Bowel Project (NSABP) has been instrumental in changing the paradigm of the surgical management of both invasive and noninvasive breast cancer that was founded on Halstedian principles of tumor growth and dissemination. Several randomized trials (B-04, B-06, B-17) have demonstrated that the extent of local therapy is not paramount to patient's survival.1-3 As a result of these trials as well as those conducted by other groups,4,5 disfiguring operations developed a century ago, such as radical mastectomy, have now been replaced in the majority of cases by the more cosmetically acceptable and less function-impairing lumpectomy.
The NSABP B-04 trial was set up as 2 companion trials conducted in parallel, one for patients with clinically node-negative breast cancer and the other for those with clinically node-positive disease. Since radical mastectomy was the standard of care at that time, this operation was included as the control arm for both trials. One thousand seventy-nine patients with clinically node-negative disease were randomized to radical mastectomy (362 patients), total mastectomy plus local-regional/axillary irradiation (352 patients), or total mastectomy alone, with no targeted axillary treatment (365 patients). For patients presenting with clinically suspicious disease in the axilla, 586 patients were randomized to radical mastectomy (292 patients) or total mastectomy plus radiation (294 patients). The most recent update from the B-04 trial after 25 years of follow-up6 continues to demonstrate no significant differences in long-term outcome between clinically node-negative patients who received radical mastectomy and those who received total mastectomy with or without nodal irradiation, or between clinically node-positive patients who received radical mastectomy and those who received total mastectomy with nodal irradiation. Among women with clinically negative nodes, the hazard ratio for death among those who were treated with total mastectomy and irradiation as compared with those who underwent radical mastectomy was 1.08 (95% CI 0.91–1.28, p = 0.38), and the hazard ...