Factors Associated with PFS
| Total no. of… | Median survival (mos) | Univariate analysis | Multivariate analysis | ||||||
| Variable | Patients | Patients with progressive disease | P | Hazard ratio | 95% confidence interval for hazard ratio | P | Hazard ratio | 95% confidence interval for hazard ratio | |
| ER* | |||||||||
| Negative | 12 | 12 | 6.78 | — | 1.00 | — | |||
| Positive | 43 | 36 | 8.54 | 0.06 | 0.52 | 0.26–1.02 | |||
| HER2 | |||||||||
| Nonamplified | 46 | 39 | 8.35 | — | 1.00 | — | |||
| Amplified | 9 | 9 | 8.08 | 0.38 | 1.40 | 0.67–2.91 | |||
| Line of therapy | |||||||||
| First line | 19 | 17 | 15.21 | — | 1.00 | — | |||
| Later | 36 | 31 | 7.11 | 0.09 | 1.67 | 0.92–3.06 | |||
| Metastatic site | |||||||||
| Bone only | 26 | 22 | 8.35 | — | 1.00 | — | |||
| Bone plus soft tissue | 29 | 26 | 8.08 | 0.92 | 0.97 | 0.55–1.72 | |||
| Baseline CTC count | |||||||||
| <5 | 19 | 15 | 8.08 | — | 1.00 | — | |||
| ≥5 | 36 | 33 | 8.35 | 0.78 | 1.09 | 0.59–2.02 | |||
| Follow-up CTC count* | |||||||||
| <5 | 33 | 28 | 14.42 | — | 1.00 | — | |||
| ≥5 | 22 | 20 | 5.32 | 0.02 | 2.02 | 1.11–3.65 | |||
| PET/CT follow-up assessment* | |||||||||
| Nonprogression | 38 | 31 | 14.42 | — | 1.00 | — | — | 1.00 | — |
| Progression | 17 | 17 | 4.53 | <0.0001 | 7.14 | 3.25–15.70 | <0.0001 | 7.14 | 3.25–15.70 |
↵* Factors with P value < 0.10 from univariate analysis are included in multivariate analysis.