Centre	No	Outcome*				Actual management†
		Benign	Malignant	Uncertain		Surgery	Conservative	Unknown
Malmö, Sweden	794	657	78	59		306	464	24
Rome, Italy‡	681	414	173	94		385	225	71
Athens, Greece‡	567	427	68	72		378	120	69
Leuven, Belgium‡	501	356	94	51		212	267	22
Genk, Belgium	406	312	44	50		224	152	30
Milan, Italy‡	367	193	161	13		288	70	9
Stockholm, Sweden‡	363	192	140	31		257	97	9
Monza, Italy‡	267	163	82	22		152	104	11
Cagliari, Italy	166	135	25	6		123	40	3
Katowice, Poland‡	139	110	17	12		45	83	11
Pamplona, Spain‡	111	65	27	19		54	40	17
Trieste, Italy	111	93	16	2		48	63	0
Milan 2, Italy‡	98	53	42	3		58	38	2
London, UK	97	79	5	13		15	78	4
Milan 3, Italy	91	80	1	10		28	55	8
Florence, Italy	85	68	2	15		31	46	8
Nottingham, UK	61	44	3	14		34	16	11
Oncology centres	3094	1973 (64)	804 (26)	317 (10)		1829 (59)	1044 (34)	221 (7)
Other centres	1811	1468 (81)	174 (10)	169 (9)		809 (45)	914 (50)	88 (5)
Total	4905	3441 (70)	978 (20)	486 (10)		2638 (54)	1958 (40)	309 (6)

^*Table 2 presents criteria for uncertain outcome. When outcome was uncertain, multiple imputation was used to classify the mass as benign or malignant at inclusion. In one sensitivity analysis a broader definition of uncertain outcome was used.

^†Conservative management means that surgery could be performed at any time during follow-up. Unknown management means that no information was available after inclusion scan.

^‡Oncology centre.