RT-2	Administration of radiotherapy after breast-conserving therapy (BCT)
Grade of recommendation A	a. The target volume of percutaneous adjuvant radiotherapy should encompass the entire residual breast and the adjoining chest wall.
Level of evidence 1a	(EBCTCG 2011: Darby S et al. 2011; EBMG 2006; NCCN 2007; NHMRC2001; NICE 2009; NZGG 2009; SIGN 2005)
Grade of recommendation A	b. The dose should be approx. 50 Gy in conventional fractionation (5 × 1.8–2.0 Gy/week).
Level of evidence 1a	(Clarke M et al. 2005; EBCTCG 2011: Darby S et al. 2011; EBMG 2006; NCCN 2011; NHMRC2001; Peto R 2006; SIGN 2005)
Grade of recommendation B	c. In older patients without locoregional lymph node involvement and with tumors < 5 cm who do not require chemotherapy, hypofractionated regimens can also be used as an alternative to conventionally fractionated radiotherapy for percutaneous homogeneous irradiation of the breast (e.g., 5 × 2.666 Gy per week up to 40 Gy).
Level of evidence 1a	(Goldhirsch A et al. 2011; Harnett A 2010; NCCN 2011; NICE 2009; Smith BD et al. 2011a; Whelan TJ et al. 2010)
Grade of recommendation A	d. The application of a local booster dose (boost irradiation) to the tumor bed reduces the rate of local recurrence in the breast without conferring an advantage in terms of survival.Boost irradiation is generally indicated. The recommended boost dose is (10–)16 Gy in conventional fractionation (5 × 1.8–2.0 Gy/week).
Level of evidence 1a	(Antonini N et al. 2007; Bartelink H et al. 2007; Jones HA et al. 2009; Livi L et al. 2009; Poortmans P 2007; Poortmans PM et al. 2008; Poortmans PM et al. 2009; Romestaing P et al. 1997; Romestaing P et al. 2009; Sautter-Bihl ML et al. 2007; SIGN 2005)
Grade of recommendation C	e. In postmenopausal patients with a very low risk of local recurrence (in particular, age > 60 years, small tumors and favorable prognostic factors), the absolute advantage conferred by boost irradiation is small. In this subgroup, the administration of boost irradiation may be omitted if necessary.
Level of evidence 2a	(EBCTCG 2011: Darby S et al. 2011; NZGG 2009)