Table 1.

Studies included for systematic review showing key study parameters.

Study	Tr.	No. P.	No. T. n/$\overline{\mathit{x}}$/%s	Size†‡	EHM%	CR/R0%	FU†	OS $\tilde{\mathit{x}}$/3Y/5Y	DFS†	Positive Prognostic Factors
Bai et al. [12]	RFA	69	135/2/51	2.9 (1–6)	46	88	26	26/25/11	24	Small tumor size, positive hormone receptor status, margin size, no EHD
Carrafiello et al. [13]	RFA	13	21/1.6/62	3.5 (0.5–7)†	46	67	12.9	10.9/NR/NR	NR	NR
Jakobs et al. [12]	RFA	43	111/2.6/NR	2.1 (0.5–8.5)‡	42	86	37	58.6/NR/NR	10.5	No EHD
Kumler et al. [14]	RFA	32	NR/2/26	2 (0.9–5)†	47	78	NR	33.5/48/NR	11	NR
Lawes et al. [15]	RFA	19	46/2.4/58	3‡	58	63	15	NR/NR/NR	NR	NR
Meloni et al. [16]	RFA	52	87/1.7/NR	2.5 (0.7–5)‡	52	25	19	29.9/43/27	NR	BCLM < 2.5 cm
Sofocleus et al. [17]	RFA	12	14/1.2/86	NR	83	5	22.5	60/70/30	12	NR
Veltri et al. [18]	RFA	45	87/1.9/6	2.3 (1–4.5)†	40	74	30	NR/44/NR	8	NR
Zhang et al. [19]	CRA	17	39/2/18	3.5 (2–5)†	NR	8785	NR	NR/NR/NR	NR	NR
Bale et al. [20]	SRFA	26	64/2.5/17	2 (0.4–0.5)† 14% > 5	31	92	23	29.3/NR/NR	31.6	NR
Abbott et al. [21]	HR	86	NR/NR/62	15% > 5†	28	NR	62	57/NR/NR	14.2	Positive hormone receptor status, preoperative stable disease
Adam et al. [3]	HR	85	NR/NR/37	2.8 (1–19)†	32	65	38	32/NR/37	12	Response to preoperative chemotherapy, R0/R1 resection
Bacalbasa et al. [22]	HR	67	NR/NR/49	NR	NR	93	NR	NR/94/69	NR	Positive hormone receptor status
Dittmar et al. [23]	HR	34	50/1.5/35	4 (0–13)†	18	62	NR	36/NR/28	NR	HER2 expression, no EHD, age <50 years
Caralt et al. [24]	HR	12	NR/NR/NR	NR	8	83	36	36/79/33	NR	NR
Carlini et al. [25]	HR	17	NR/NR/88	NR	0	NR	NR	NR/NR/46	53	NR
Elias et al. [26]	HR	42	209/5/18	3.2 (0.4–11.1)†	17	82	32	34/50/34	16	Positive hormone receptor status
Ercolani et a. [27]	HR	51	NR/NR/47	4 (1–11)†	0		61	51/69/36	41	Small tumor diameter, Positive hormone receptor status, triple negative status
He et al. [28]	HR	67	NR/NR/64	4.2 ± 2.2‡	21	96	NR	NR/74/32	NR	>2 years between primary and BCLM
Hoffman et al. [29]	HR	41	NR/2/49	15% > 5	29	78	34	58/75/31	34	R0/R1, Late onset of BCLM
Kostov et al. [30]	HR	42	NR/NR/52	5.1 (1.4–9)†	48	83	60	43/64/38	29	BCLM size <4 cm, R0, negative portal LN, Response to CTX, positive hormone receptor status
Lubrano J et al. [31]	HR	16	0/0/75	3.5 (1–10)†	0		28	42/61/33	NR	Negative hormone receptor status, low number of metastases, minor surgery, age >50, isolated BCLM
Margonis et al. [32]	HR	131	NR/1/NR	3 (2–5)†	13	91	24	53/75/NR	24	Negative margin (R0), small diameter of the liver metastasis
Mariani et al. [33]	HR	100	NR/NR/65	1.8 (0.5–11)†	7	86	NR	NR/73/5	NR
Martinez et al. [34]	HR	20	NR/NR/NR	NR	NR		39	32/61/33	NR	Anatomic resections, positive hormone receptor status, age >50 years
Ruiz et al. [10]	HR	139	322/2.3/41	1.8	0	NR	69	73/78/57	NR	NR
Selzner et al. [35]	HR	17	22/1.3/71	2.5 (1.5–5)†	18		17	24/NR/22	NR	Late onset of BCLM
van Walsum et al. [36]	HR	32	NR/NR/69	2.5 (0.5–9)†	16	69	26	55/NR/37	11	Solitary BCLM
Pocard 2001 et al. [37]	HR	52	NR/NR/69	3.8 (0.4–12)†	23	86	23	42/49/NR	NR	Late onset of BCLM, low N stage
Sabol et al. [38]	HR	15	31/2/6	2.2 (0.2–6.6)†	33	1	NR	53/67/38	NR	NR
Sakamoto et al. [39]	HR	34	NR/NR/0	4 (1.3–8)†	26	NR	72	36/52/21	NR	No EHD
Weinreich et al. [40]	HR	21	NR/NR/55	NR	0	NR	22	53/83/33	NR	R0 resection, low T- and N-stages as well as a low-grade histopathology of the primary tumor
Vertriest et al. [41]	HR	27	38/1.4/56	3.9 ± 2.3‡	4	89	52	116/83/78	NR	Stage of primary tumor, Solitary lesions
Yoshimoto et al. [42]	HR	25	NR/NR/56	4.1 (1.3–7)†	32	NR	NR	34/NR/27	24	NR
Onal et al. [43]	SBRT	22	29/1.3/86	2.1‡	32	88	16	NR/NR/NR	7.4	NR
Mahadevan et al. [44]	SBRT	42	NR/NR/NR	NR	NR	NR	14	22/14/5	NR	BCLM < 40 cm3; BED10 ≥ 100 Gy
Wieners et al. [45]	BT	41	115/NR/	4.6 (1.5–11)†	NR	94	18	NR/NR/NR	NR	Extent of pre-treatment
Cianni et al. [46]	SIRT	52	NR/NR/0	NR	46	0	NR	11.5/NR/NR	NR	NR
Fendler et al. [47]	SIRT	81	NR/NR/0	NR	67	0	NR	8.7/0/0	NR	NR
Gordon et al. [48]	SIRT	75	NR/NR/15	NR	77	NR	NR	6.6/NR/NR	3.2	Solitary BCLM, Tumor burden
Haug et al. [49]	SIRT	58	NR/NR/NR	NR	66	NR	2.3	4/NR/NR	NR	Responder
Jakobs et al. [50]	SIRT	30	NR/NR/0	NR	57	0	14	11.7/NR/NR	NR	No EHD
Pieper et al. [51]	SIRT	44	NR/NR/2	NR	89	0	4	6.1/0/0	3.4 TTP	ECOG status <1, small liver tumor burden, No EHD, response, vascularity
Saxena et al. [52]	SIRT	40	NR/NR/0	NR	6	5	11.2	13.6/0/0	6.8 TTP	Low tumor burden, CTX after SIRT, response
Eichler et al. [53]	TACE	43	NR/NR/NR	NR	49	02	4	10.2/NR/NR	3.3	Low vascularized tumors
Li et al. [54]	TACE	28	NR/NR/32	2.8 (1–8)†	40	07	28	28/13/NR	NR	N status of the primary tumor, clinical stage of BCLM, Child–Pugh grade

Tr. = Local treatment, No. P. = number of patients, No. T. T/$\overline{x}$/%s = number of tumors, total number/mean/% solitary, EHD = extrahepatic disease, BCLM = breast cancer liver metastases, CR = complete response, $\tilde{x}$, † = median, $\overline{x}$, ‡ = mean, FU = follow-up, NR = not reported, HR = hepatic resection, RFA = radiofrequency ablation, SRFA = stereotactic radiofrequency ablation, SBRT = stereotactic body radiation therapy, TACE = transarterial chemoembolization, BT = brachytherapy, CRA = cryoablation, SIRT = selective internal brachytherapy, BED = radiation biologically effective dose, ECOG = eastern cooperative oncology group, CTX = chemotherapy.