Effect of Central Nervous System Metastases on Treatment Discontinuation and Survival in Older Women Receiving Trastuzumab for Metastatic Breast Cancer
Table 4
Adjusted model for risk of death.
Characteristic
Adjusted HR (95% CI)
P-Value
Metastases present at trastuzumab initiation
Bone
1.17 (0.75–1.84)
0.49
Liver
2.03 (1.55–2.64)
<0.001
Lung/chest
1.36 (1.04–1.78)
0.02
Other
0.72 (0.53–0.96)
0.03
Diagnosed with metastases after start of trastuzumab*
CNS
2.49 (1.84–3.37)
<0.001
Bone
1.34 (0.93–1.94)
0.12
Liver
2.72 (1.93–3.84)
<0.001
Lung/Chest
1.39 (0.98–1.97)
0.07
Other
1.91 (1.31–2.78)
0.001
Discontinued trastuzumab therapy*
No
1.00 (ref)
<0.001
Yes
2.44 (1.90–3.15)
Hospital inpatient*
No
1.00 (ref)
<0.001
Yes
7.04 (5.32–9.32)
Age at start of trastuzumab
66–69
1.00 (ref)
70–74
1.17 (0.80–1.69)
0.42
75–79
1.17 (0.80–1.72)
0.42
≥80
1.24 (0.84–1.81)
0.28
Race/ethnicity
White
1.00 (ref)
0.22
Non-White
1.21 (0.89–1.63)
Time from MBC diagnosis to trastuzumab initiation
Per ln (days)
1.07 (0.98–1.15)
0.12
NCI comorbidity score at start of trastuzumab
0
1.00 (ref)
1
1.27 (0.80–2.01)
0.31
≥2
0.95 (0.48–1.85)
0.87
Cardiovascular disease*
Yes
3.23 (2.43–4.30)
<0.001
Stage at diagnosis
Recurrent Stage 0–III
1.00 (ref)
0.23
Incident Stage IV
0.86 (0.66–1.10)
ER/PR Status
Hormone Positive
1.00 (ref)
Hormone Negative
1.06 (0.81–1.40)
0.67
Unknown
1.40 (0.96–2.05)
0.08
Asterisk (*) indicates time varying covariate. All listed covariates were included in one model. Nonwhite race includes Black, Hispanic and Other as a combined category. Baseline defined as the date of trastuzumab initiation. Year of trastuzumab initiation (not significant) was also included as a covariate but results are not shown. Discontinuation was defined to be at least 60 days with no therapy. Reference group for cardiovascular disease and for each metastasis covariate is the absence of the condition (HR = 1.0).
