Partial Breast Versus no Irradiation for Women With Early Breast Cancer

Inclusion Criteria: Female patient \>=60 years Primary tumour characteristics by conventional histopathology * unilateral and unifocal non-lobular histology grade 1-2 * maximum microscopic size \<=20mm * node negative determined by sentinel node or axillary lymph node dissection * estrogen receptor \>=10% positive * HER2 negative (by IHC and/or in situ hybridization) * resection margin \>=2 mm for invasive carcinoma and any ductal carcinoma in situ associated with the cancer Surgical type is breast conservation Performance status ECOG 0-2 No evidence of distant metastasis Exclusion Criteria: * multifocal or multicentric invasive carcinoma or ductal carcinoma in situ * evidence of clinical or pathological T4 breast cancer * grade 3 malignancy * previous breast cancer or DCIS irrespective of disease-free interval * previous radiation therapy to the breast or thorax, * previous neoplasm within 5 years except carcinoma in situ of the cervix, endometrium or coli, melanoma in situ. * comorbidity precluding the patient from radiation therapy (e.g. cardiovascular or pulmonary disease, scleroderma, systemic lupus erythematosus). * mental/psychiatric disorder which precludes the patient from understanding the randomization and the follow up. * documented hereditary breast cancer or with high genetic risk of breast cancer * life expectancy \<10 years