Table 1.
Cohort demographic characteristics and exposures
| Cohort N | Total | White | Black | P value |
|---|---|---|---|---|
| 15,256 | 11,775 | 3,481 | ||
| Breast cancer deaths/person years | 1,737/97,468 | 1,125/76,837 | 612/20,631 | |
| Breast cancer mortality rate/1,000 person years | 17.8 | 14.6 | 29.7 | |
| Mean years of follow-up | 6.4 | 6.5 | 5.9 | |
| Age at diagnosis (mean) | 59.3 | 60.0 | 57.1 | <0.001 |
| Marital status at diagnosis (%) | ||||
| Single | 9.6 | 6.8 | 19.0 | <0.001 |
| Married | 58.3 | 64.1 | 38.7 | |
| Sep/Div/Widowed | 32.1 | 29.1 | 42.3 | |
| Stage at diagnosis (%) | ||||
| In situ | 18.5 | 18.5 | 18.4 | <0.001 |
| Local | 49.3 | 51.7 | 41.3 | |
| Regional | 26.4 | 24.9 | 31.4 | |
| Distant | 3.6 | 2.9 | 6.1 | |
| Unstaged | 2.2 | 2.1 | 2.7 | |
| Surgery | ||||
| None | 4.4 | 3.4 | 7.5 | <0.001 |
| Some surgery | 94.2 | 95.3 | 90.5 | |
| Unknown | 1.5 | 1.3 | 2.0 | |
| Tract% Black (mean) | 26.8 | 16.4 | 61.9 | <0.001 |
| Tract% below poverty (mean) | 10.5 | 8.3 | 17.8 | <0.001 |
| Tract per capita income (mean) | $24,957 | $26,960 | $18,179 | <0.001 |
| Gravity access to oncologists (median of log-transformed value)a | ||||
| Friction parameter = 1 | −10.1 | −10.3 | −9.4 | <0.001 |
| Friction parameter = 1.5 | −10.3 | −10.5 | −9.6 | <0.001 |
| Friction parameter = 2 | −10.7 | −10.9 | −9.9 | <0.001 |
aLog-median gravity access is a relative measure of potential spatial access to board-certified oncologists, with larger numbers indicating greater relative access. Friction parameter is user-specified indicator of distance decay rate