WHO performance status 0-1

Invasive Breast Cancer with cT1-3 cN1-2 at time of diagnosis

Axillary nodal involvement can be detected using, clinical examination, ultrasound, CT scan or PET scan

Pathologic confirmation using, FNAC, core biopsy or excisional biopsy

ER, PR, Her2 neu and Ki67 status should be available for all patients

All patients should have received standard preoperative chemotherapy prior to surgery

At the time of surgery, all patients should have axillary clearance with at least 6 nodes harvested from the axilla

Patients who have undergone mastectomy or lumpectomy with negative margins with ypN0, ypN0(+i) or ypN0(+mol) are eligible for randomization

Radiation Therapy for ypN0 Breast Cancer