Following Patients for More than a Decade:  The NCI-supported National Surgical Adjuvant Breast and Bowel Project (NSAABP), now part of NRG Oncology, led the US phase 3 trial.  NSABP researchers randomly assigned 4,216 patients with breast cancer who had recently received a lumpectomy to treatment with APBI or WBI.  Of this group, 25% had ductal carcinoma in situ (DCIS), 65%  had stage 1 breast cancer, and 10% had stage 2 breast cancer.  Eighty-one percent of the patients had hormone receptor-positive cancer, and 61% of the patients were postmenopausal.  Women assigned to APBI received either brachytherapy (an internal form of radiation therapy) or three-dimensional conformal external beam radiation therapy (3D-CRT).  After a median follow-up of 10.2 years, 161 patients had a breast cancer recurrence: 90 patients who received APBI and 71 who received WBI.  There were modest differences between the groups in terms of side effects.

Source: NCI