Exploring the Value of Additional Primary Tumour Excision Combined with Systemic Therapy Administered in Different Sequences for Patients with de Novo Metastatic Breast Cancer

Table 3

Univariate and multivariate analysis of BCSD: a competing risk regression model.

Variables	Univariate analysis		Multivariate analysis
	SHR (95% CI)	-value	SHR (95% CI)	-value
Treatment modality
Systemic therapy without primary surgery	1 [Reference]	NA	1 [Reference]	NA
Systemic therapy after primary surgery	0.73 (0.69–0.77)	<0.001	0.74 (0.69–0.79)	<0.001
Systemic therapy before primary surgery	0.67 (0.62–0.73)	<0.001	0.62 (0.56–0.67)	<0.001
Treatment modality (reference category changed)
Systemic therapy without primary surgery	—	—	—	—
Systemic therapy after primary surgery	1 [Reference]	NA	1 [Reference]	NA
Systemic therapy before primary surgery	0.92 (0.84–1.01)	0.07	0.83 (0.76–0.92)	<0.001
Year of diagnosis
As a continuous variable	0.95 (0.94–0.96)	<0.001	0.94 (0.93–0.95)	<0.001
Age, y
(18, 40)	1 [Reference]	NA	1 [Reference]	NA
(40, 60)	1.14 (1.04–1.24)	0.003	1.13 (1.04–1.23)	0.006
(60, 100)	1.25 (1.15–1.36)	<0.001	1.28 (1.18–1.40)	<0.001
Marital status
Unmarried	1 [Reference]	NA	1 [Reference]	NA
Married	0.85 (0.82–0.89)	<0.001	0.91 (0.86–0.95)	<0.001
Unknown	0.95 (0.85–1.06)	0.36	0.96 (0.85–1.07)	0.46
Race
White	1 [Reference]	NA	1 [Reference]	NA
Black	1.35 (1.27–1.43)	<0.001	1.20 (1.12–1.28)	<0.001
Other	0.94 (0.86–1.03)	0.16	0.95 (0.87–1.04)	0.27
Unknown	0.50 (0.29–0.86)	0.01	0.49 (0.28–0.85)	0.01
Sex
Female	1 [Reference]	NA	—	—
Male	0.98 (0.79–1.2)	0.83	—	—
Histologic type
IDC	1 [Reference]	NA	1 [Reference]	NA
ILC	0.99 (0.92–1.06)	0.70	1.25 (1.15–1.36)	<0.001
Other	1.15 (1.09–1.22)	<0.001	1.08 (1.01–1.16)	0.02
Grade
I	1 [Reference]	NA	1 [Reference]	NA
II	1.22 (1.10–1.35)	<0.001	1.22 (1.10–1.36)	<0.001
III/IV	1.81 (1.63–2.00)	<0.001	1.63 (1.47–1.82)	<0.001
Unknown	1.66 (1.49–1.85)	<0.001	1.36 (1.22–1.53)	<0.001
AJCC T category
0/1	1 [Reference]	NA	1 [Reference]	NA
2	1.08 (1.00–1.17)	0.05	1.12 (1.03–1.22)	0.008
3	1.36 (1.24–1.48)	<0.001	1.26 (1.15–1.38)	<0.001
4	1.54 (1.42–1.66)	<0.001	1.32 (1.21–1.44)	<0.001
X	1.43 (1.31–1.57)	<0.001	1.23 (1.11–1.36)	<0.001
AJCC N category
0	1 [Reference]	NA	1 [Reference]	NA
1	1.03 (0.97–1.09)	0.34	0.96 (0.90–1.03)	0.27
2	1.03 (0.95–1.12)	0.42	1.04 (0.95–1.13)	0.42
3	1.18 (1.09–1.27)	<0.001	1.10 (1.01–1.19)	0.03
X	1.24 (1.12–1.37)	<0.001	0.99 (0.88–1.11)	0.83
Molecular subtype
HR+/HER2−	1 [Reference]	NA	1 [Reference]	NA
HR+/HER2+	0.81 (0.76–0.87)	<0.001	0.70 (0.65–0.75)	<0.001
HR−/HER2+	1.02 (0.94–1.11)	0.60	0.86 (0.78–0.94)	<0.001
HR−/HER2–	2.52 (2.36–2.70)	<0.001	2.15 (1.99–2.32)	<0.001
Unknown	1.27 (1.17–1.37)	<0.001	1.06 (0.97–1.16)	0.20
Site of metastasis
Bone only	1 [Reference]	NA	1 [Reference]	NA
Viscera only	1.23 (1.16–1.31)	<0.001	1.06 (0.99–1.14)	0.10
Bone + viscera	1.62 (1.54–1.71)	<0.001	1.09 (0.94–1.25)	0.26
Brain involvement	2.26 (2.08–2.47)	<0.001	1.38 (1.18–1.60)	<0.001
Number of sites of metastasis
1	1 [Reference]	NA	1 [Reference]	NA
2	1.50 (1.43–1.58)	<0.001	1.33 (1.17–1.52)	<0.001
≥3	2.06 (1.91–2.22)	<0.001	1.66 (1.43–1.94)	<0.001
Radiation therapy
None/unknown	1 [Reference]	NA	1 [Reference]	NA
Yes	1.07 (1.02–1.12)	0.005	1.06 (1.00–1.12)	0.04
Non-primary surgical procedure to distant site
No	1 [Reference]	NA	1 [Reference]	NA
Yes	0.83 (0.73–0.96)	0.009	0.80 (0.69–0.93)	0.003
Unknown	0.79 (0.62–1.00)	0.05	0.92 (0.73–1.17)	0.52

Abbreviations: SHR, subdistribution hazard ratio; CI, confidence interval; NA, not applicable; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma.