Table 2.
Comparisons of progression-free survival, time on treatment, and overall survival, between patients with multiple metastases versus single metastasis
| Parameters | Progression-free survival | Time on treatment | Overall survival | ||||||
|---|---|---|---|---|---|---|---|---|---|
| HR | (95 % CI) | P-value | HR | (95 % CI) | P-value | HR | (95 % CI) | P-value | |
| Univariate analysis | |||||||||
| Multiple metastases (Ref: single metastasis) | 1.98 | (1.59,2.46) | <0.001* | 1.78 | (1.46, 2.18) | <0.001* | 2.61 | (1.78, 3.83) | <0.001* |
| Multivariable-adjusted analysisa | |||||||||
| Multiple metastases (Ref: single metastasis) | 1.55 | (1.21,1.98) | <0.001 | 1.33 | (1.05, 1.67) | 0.018* | 1.77 | (1.15, 2.74) | 0.010* |
| Age at index therapy initiation | 0.98 | (0.97,1.00) | 0.043* | 0.97 | (0.95, 0.99) | <0.001* | 1.01 | (0.98, 1.04) | 0.646 |
| Race (Ref: non-white) | |||||||||
| White | 0.89 | (0.71,1.12) | 0.331 | 0.83 | (0.67, 1.02) | 0.074 | 0.88 | (0.61, 1.29) | 0.527 |
| Insurance at mBC diagnosis (Ref: other or no insurance) | |||||||||
| Private | 1.35 | (0.85,2.14) | 0.203 | 1.23 | (0.81, 1.87) | 0.326 | 1.12 | (0.50, 2.50) | 0.787 |
| Medicare only | 1.47 | (0.89,2.42) | 0.128 | 1.46 | (0.93, 2.31) | 0.103 | 1.27 | (0.53, 3.04) | 0.584 |
| Type of index treatment (Ref: endocrine therapyb) | |||||||||
| Chemotherapyc | 1.18 | (0.91,1.55) | 0.216 | 2.29 | (1.80, 2.90) | <0.001* | 1.84 | (1.20, 2.81) | 0.005* |
| Line of index treatment (Ref: first-line) | |||||||||
| Second-line | 1.49 | (1.06,2.09) | 0.023* | 1.75 | (1.27, 2.41) | 0.001* | 1.26 | (0.69, 2.29) | 0.448 |
| Third-line and above | 1.34 | (0.93,1.93) | 0.114 | 1.18 | (0.84, 1.65) | 0.337 | 0.85 | (0.44, 1.63) | 0.618 |
| mBC type (Ref: de novo) | |||||||||
| Recurrent with adjuvant endocrine therapy | 1.27 | (0.90,1.78) | 0.175 | 1.53 | (1.11, 2.12) | 0.010* | 1.40 | (0.73, 2.64) | 0.316 |
| Recurrent without adjuvant endocrine therapy | 0.40 | (0.25,0.66) | <0.001* | 0.45 | (0.29, 0.71) | 0.001* | 1.06 | (0.49, 2.31) | 0.882 |
| Adjusted CCI at index treatment initiation | 1.08 | (0.97,1.20) | 0.155 | 1.09 | (0.99, 1.21) | 0.084 | 1.20 | (1.02, 1.40) | 0.024* |
| Bone metastasis at index therapy initiation | |||||||||
| (Ref: no bone metastasis) | 1.56 | (1.20,2.02) | 0.001* | 1.15 | (0.91, 1.45) | 0.233 | 0.85 | (0.57, 1.27) | 0.418 |
| Performance status at index treatment initiation (Ref: ECOG 0) | |||||||||
| ECOG 1 | 1.44 | (1.06,1.97) | 0.021* | 1.04 | (0.79, 1.37) | 0.785 | 1.76 | (0.93, 3.32) | 0.080 |
| ECOG 2 and 3 | 2.60 | (1.70,3.98) | <0.001* | 1.87 | (1.26, 2.78) | 0.002* | 5.04 | (2.45, 10.40) | <0.001* |
| Unknown | 1.77 | (1.20,2.62) | 0.004* | 1.29 | (0.90, 1.83) | 0.166 | 3.15 | (1.47, 6.72) | 0.003* |
| Use of chemotherapy for mBC before index treatment initiation | 0.82 | (0.58,1.17) | 0.283 | 0.89 | (0.65, 1.23) | 0.484 | 2.02 | (1.15, 3.55) | 0.014* |
| Duration from initiation of last adjuvant endocrine therapy to mBC diagnosis | 1.00 | (0.99,1.00) | 0.374 | 1.00 | (0.99, 1.00) | 0.016* | 1.00 | (0.99, 1.01) | 0.671 |
BC breast cancer, CCI Charlson Comorbidity Index, CI confidence interval, ECOG Eastern Cooperative Oncology Group, HR hazard ratio, mBC metastatic breast cancer, Ref reference
* P < 0.05; Ref reference group
aThe model adjusted for age, race, insurance type at mBC diagnosis, treatment type, line of the index treatment, mBC type, adjusted CCI, bone metastasis at index therapy initiation, ECOG performance status, prior chemotherapy for mBC, and months from the initiation of the last adjuvant endocrine therapy to mBC diagnosis
bEndocrine therapy includes endocrine monotherapy, combination therapy with another endocrine agent, and everolimus-based therapies
cChemotherapy includes chemotherapy monotherapy, combinational therapy of chemotherapy agents, and combinational therapy of chemotherapy and endocrine therapy