Table 2.
Median overall survival (OS) across age, facility type, Charlson-Deyo score, breast cancer subtype, number of extracranial metastatic sites, location of extracranial metastatic sites, brain metastasis treatment modality, breast cancer treatment modality, and treatment combinations
| Age | # of Cases | Median OS | 95% CI |
|---|---|---|---|
| ≤ 50 years | 1022/1501 | 18.96 | 16.92, 20.86 |
| 51–60 years | 1538/2054 | 12.98 | 11.89, 14.13 |
| 61–70 years | 1651/2183 | 10.55 | 9.50, 11.83 |
| ≥ 70 years | 1266/1523 | 4.70 | 4.07, 5.29 |
| Total | 5477/7261 | ||
| Log-rank test p-value | < .0001 | ||
| Facility type | |||
| Academic/research program | 1755/2445 | 13.63 | 12.19, 15.00 |
| Community cancer program | 472/611 | 9.89 | 7.75, 11.37 |
| Comprehensive community cancer program | 2097/2650 | 9.26 | 8.38, 9.89 |
| Integrated network cancer program | 864/1117 | 9.26 | 8.02, 10.55 |
| Total | 5188/6823 | ||
| Log-rank test p-value | < .0001 | ||
| Charlson Deyo score | |||
| 0 | 4251/5775 | 12.42 | 11.76, 13.17 |
| 1 | 821/1014 | 8.08 | 6.77, 9.56 |
| 2 | 249/291 | 4.90 | 3.38, 7.06 |
| ≥ 3 | 156/181 | 2.86 | 2.17, 3.78 |
| Total | 5477/7261 | ||
| Log-rank test p-value | < .0001 | ||
| Breast cancer subtype | |||
| HR( − )/HER2( − ) | 1194/1367 | 5.62 | 5.19, 6.18 |
| HR( − )/HER2( +) | 547/767 | 14.59 | 11.79, 16.95 |
| HR( +)/HER2( − ) | 2132/2936 | 15.80 | 14.46, 17.15 |
| HR( +)/HER2( +) | 655/998 | 22.05 | 18.73, 24.67 |
| Total | 4528/6068 | ||
| Log-rank test p-value | < .0001 | ||
| Number of extracranial metastatic sites | |||
| Only brain | 868/1200 | 12.00 | 10.38, 13.83 |
| Brain + 1 metastatic site | 1798/2374 | 13.17 | 12.02, 14.36 |
| Brain + 2 metastatic sites | 1562/2053 | 10.48 | 9.53, 11.83 |
| Brain + ≥ 3 metastatic sites | 1232/1613 | 7.59 | 6.70, 8.84 |
| Total | 5460/7240 | ||
| Log-rank test p-value | < .0001 | ||
| Location of extracranial metastatic sites | |||
| Only brain | 868/1200 | 12.00 | 10.38, 13.83 |
| Bone | 1127/1529 | 16.53 | 14.82, 18.40 |
| Liver | 133/161 | 6.37 | 4.57, 13.80 |
| Lung | 470/586 | 8.38 | 7.29, 9.63 |
| Bone + liver | 467/595 | 10.12 | 7.79, 12.09 |
| Bone + lung | 712/931 | 11.99 | 10.28, 13.73 |
| Liver + lung | 200/232 | 5.22 | 3.09, 6.34 |
| Bone + liver + lung | 671/805 | 6.83 | 5.49, 8.05 |
| Other | 812/1201 | 9.56 | 8.08, 10.91 |
| Total | 5460/7240 | ||
| Log-rank test p-value | < .0001 | ||
| Brain metastasis treatment modality | |||
| No treatment | 2816/3729 | 9.26 | 8.31, 10.02 |
| WBRT | 1725/2125 | 10.25 | 9.56, 11.10 |
| SRS | 442/651 | 15.41 | 13.24, 18.53 |
| Surgery | 246/358 | 19.81 | 14.78, 25.43 |
| Surgery + SRS | 165/249 | 20.5 | 16.26, 23.98 |
| Surgery + WBRT | 83/149 | 32.33 | 23.98, 40.44 |
| Total | 5477/7261 | ||
| Log-rank test p-value | < .0001 | ||
| Breast cancer treatment modality | |||
| No treatment | 1678/1955 | 2.10 | 1.97, 2.23 |
| Immunotherapy | 60/74 | 5.00 | 3.32, 8.41 |
| Chemotherapy | 1507/1817 | 10.50 | 9.86, 11.24 |
| Hormonal therapy | 967/1225 | 13.54 | 12.02, 15.11 |
| Immunotherapy + hormonal therapy | 103/154 | 23.69 | 17.74, 27.56 |
| Chemotherapy + hormonal therapy | 680/1071 | 26.38 | 24.71, 28.55 |
| Chemotherapy + immunotherapy | 345/647 | 27.56 | 24.77, 33.31 |
| Chemotherapy + hormonal therapy + immunotherapy | 133/307 | 42.35 | 35.48, 54.14 |
| Total | 5473/7250 | ||
| Log-rank test p-value | < .0001 | ||
| Treatment combination | |||
| No treatment for both | 1082/1275 | 1.77 | 1.64, 1.97 |
| Treatment for brain metastasis only | 600/691 | 2.63 | 2.33, 2.96 |
| Treatment for breast cancer only | 1734/2454 | 16.92 | 16.00, 18.27 |
| Treatment for both | 2061/2841 | 16.30 | 15.11, 17.38 |
| Total | 5477/7261 | ||
| Log-rank test p-value | < .0001 |