[METHODS] Parameters to identify eligible patients are as follows : ESTRO : > 50 years , invasive ductal carcinoma/other favorable histology ( IDC ) , T1-2 ( 3 cm ) , N0 , any hormone receptor status , M0 ; ASTRO : 60 years , IDC , T1 , N0 , positive estrogen hormone receptor status , M0 ; TARGIT E `` elderly '' , risk adapted radiotherapy with IORT followed by external beam radiotherapy in case of risk factors in final histopathology , phase II : 70 years , IDC , T1 , N0 , any hormone receptor status , M0 ; TARGIT C `` consolidation '' , risk adapted radiotherapy , phase IV : 50 years , IDC , T1 , N0 , positive hormone receptor status , M0 ; TARGIT BQR `` boost quality registry '' : every age , every histology , T1-2 ( max .