Table 2. Treatment outcome of SBRT for oligometastatic breast cancer.

Author/year	Number of patients	Target	Outcomes	Toxicities	Prognostic factor
Milano et al. (21)/2009	Curative intent:40 patients with 1–5 metastatic lesions	Total of 85 lesions: lung 19; liver 33; bone 17; LNs 16	Median PFS: 23 months; 2-year PFS: 44%; 4-year PFS: 38%; 4-year LC: 89%; 4-year OS: 59%	No data	Metastasis to only one lesion; small in size; bone only metastasis; stable or regressing with systemic therapy metastases before SBRT
	Palliative intent: 11 patients with more than 6 metastatic lesions; SBRT for only potentially fatal lesions	Total of 23 lesions: lung 6; liver 16; bone 1	Median OS: 13 months (4–24 months); median PFS: 4 months (3–16 months)	No data	No data
Milano et al. (22)/2012	39 patients with 1–5 metastases	Total of 47 sites: lung 11; liver 13; LNs 11; brain 1; bone 11	2-year OS 74%; 2-year freedom from widespread distant metastasis 52%; 2-year LC: 87%; 6-year OS: 47%; 6-year freedom from widespread distant metastasis 36%; 6-year LC 87%	No G4–5	The variables of bone metastases; metastasis to only one site
Scorsetti et al. (23)/2016	33 patients with less than 5 metastases within 5 cm in each size	Total of 35 lesions: lung 7; liver 28	Median PFS 11 months; 1-year LC 98%, 2.3-year LC 90%, CR 53.2%; PR 34%; PD 12.8%; median OS 48 months; 2-year OS 66%	No G3–5; nausea and vomiting G1–2 in 18%; G2 gastritis in one patient; G2 Cough in one patient	DFI >12 months; hormonal receptor-positive; medical therapies after SBRT

SBRT, stereotactic body radiation therapy; PFS, progression-free survival; LC, local control; OS, overall survival; LN, lymph node; CR, complete response; PR, partial response; PD, progressive disease; G, grade.