Table 1.

Patient characteristics in our population of interest.

Characteristic	N = 541	%
Tumour grade
Grade I/II	204	37.7
Grade III	252	46.6
NA	85	15.7
Histological type
Ductal	410	75.8
Lobular	56	10.4
Other	64	11.8
NA	11	2.0
(Neo-)adjuvant chemotherapy a
No	55	10.2
Yes	437	80.8
NA	49	9.0
Age at MBC diagnosis
<55 years	236	43.6
⩾55 years	305	56.4
Time to MBC diagnosis b
<6 months	46	8.6
6–11 months	75	13.9
12–23 months	164	30.5
24–59 months	155	28.8
⩾60 months	98	18.2
NA	3	0.6
Symptoms at MBC diagnosis
Yes	411	76
No	117	21.6
NA	13	2.4
BC Subtype
HR+/HER2−	154	28.5
HR+/HER2+	117	21.6
HR−/HER2+	107	19.8
TN	141	26.1
NA	22	4.1
Performance status
PS 0	65	12
PS 1	81	15
PS 2–4	73	13.5
NA	322	59.5
Treatment strategy c
Local and systemic	266	49.2
Only local	192	35.5
Only systemic	62	11.4
No specific therapy	21	3.9
Surgical resection (+/-systemic therapy) c ?
Surgical resection and systemic therapy	46	8.5
Surgical resection without systemic therapy	42	7.8
No surgical resection	453	83.7

HER2, human epidermal growth factor receptor 2; HR, hormone receptor; MBC, metastatic breast cancer; NA, not available; PS, performance status; TN, triple-negative.

^aThe category ‘NA’ included patients with de novo MBC.

^bDefined as the time between the diagnosis of primary cancer and the diagnosis of MBC.

^cWithin the first 3 months after CNS metastases diagnosis.