Table 1.

Characteristics of the comparative studies included in the systematic review and meta-analysis

Reference	Data accrual	SLNB procedures	SPIO	Injection volume (ml)	Injection site	Timing of injection	MINORS score
Douek et al.3	Prospective, non-randomized	160	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	23
Thill et al.4	Prospective, non-randomized	150	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	22
Rubio et al.36‡	Prospective, non-randomized	30	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	20
Rubio et al.5	Prospective, non-randomized	120	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	23
Piñeiro-Madrona et al.6	Prospective, non-randomized	181	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	24
Ghilli et al.7	Prospective, non-randomized	197	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	24
Coufal et al.8	Prospective, non-randomized	20	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	20
Ahmed et al.37	Prospective, non-randomized	32	Sienna+®	0.5 ml SPIO	Peritumoral	Peroperative	21
Houpeau et al.9	Prospective, non-randomized	108	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	24
Karakatsanis et al.10	Prospective, non-randomized	206	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	24
Karakatsanis et al.11*	Prospective, non-randomized	339	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar/peritumoral	Peroperative/preoperative	24
Karakatsanis et al.20	Prospective, non-randomized	12	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Preoperative	22
Karakatsanis et al.19§	Prospective, non-randomized	40	Sienna+®	2 ml SPIO	Subareolar/peritumoral	Preoperative	24
Alvarado et al.16	Prospective, non-randomized	146	Magtrace®	2 ml SPIO	Subareolar	Peroperative	24
Taruno et al.38†	Prospective, non-randomized	210	Ferucarbutran	1 ml SPIO	Subareolar	Peroperative	24
Makita et al.42†	Prospective, non-randomized	69	Ferucarbutran	0.5 ml SPIO	Subareolar/peritumoral	Peroperative	22
Hamzah et al.39	Prospective, non-randomized	20	Magtrace®	2 ml SPIO	Subareolar	Peroperative	20
Rubio et al.17	Prospective, randomized	135	Magtrace®	SPIO in different doses	Subareolar	Peroperative	24
Hersi et al.18	Prospective, non-randomized	328	Magtrace®	SPIO in different doses	Subareolar/peritumoral	Peroperative/preoperative	24
Giménez-Climent et al.40‡	Prospective, non-randomized	89	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar	Peroperative	22
Wärnberg et al.41¶	Prospective, observational	340	Sienna+®	2 ml SPIO diluted in 3 ml NaCl or local anaesthetic	Subareolar/peritumoral	Peroperative/preoperative	20

Head-to-head comparison between superparamagnetic iron oxide nanoparticles (SPIO) and radioisotope. All other studies had a within-patient comparison design—all patients received both tracers ± blue dye and paired comparisons were made. †Used Tokyo probe; the Sentimag^® system (Endomag, Cambridge, UK) was used in all other studies. ‡Sentinel lymph node biopsy (SLNB) after neoadjuvant treatment. §Delayed SLNB after primary surgery for ductal carcinoma in situ (SentiNot study). ¶Reported only skin-staining outcomes. MINORS, Methodological Index for Non-Randomized Studies. Sienna+^® (Endomag, Campbridge, UK); Magtrace^® (Endomag, Cambridge, UK).