Twenty-Year Follow-Up of a Randomized Trial Comparing Total Mastectomy, Lumpectomy, and Lumpectomy plus Irradiation for the Treatment of Invasive Breast Cancer

Background: The National Surgical Adjuvant Breast and Bowel Project (NSABP) B-06 trial was designed to determine whether resection of breast cancer with a margin of surrounding breast tissue and tumour-free resection margins (lumpectomy, hereafter referred to as wide local excision [WLE]) with or without radiotherapy is as effective as total mastectomy for treatment of invasive breast cancer. Objective/Research Question: The trial aimed specifically to examine the impact of radiotherapy on ipsilateral breast tumour recurrence (IBTR) and whether WLE increased the risk of distant disease and death.