Table 1.
Characteristics of patients in the cohort*
| Characteristic | No. of patients | % |
|---|---|---|
| Total | 3341 | 100% |
| Age, y | ||
| 65–69 | 1293 | 38.7 |
| 70–74 | 1167 | 34.9 |
| 75–79 | 663 | 19.8 |
| ≥80 | 218 | 6.5 |
| Race | ||
| White | 2849 | 85.3 |
| Black | 216 | 6.5 |
| Other | 276 | 8.3 |
| Census tract education, %† | ||
| <10 | 800 | 23.9 |
| 10–15.9 | 735 | 22.0 |
| 16–23.9 | 840 | 25.1 |
| ≥24 | 966 | 28.9 |
| Census tract poverty level, %‡ | ||
| <3 | 736 | 22.0 |
| 3–5.9 | 868 | 26.0 |
| 6–10.9 | 824 | 24.7 |
| ≥11 | 913 | 27.3 |
| SEER region | ||
| San Francisco | 165 | 4.9 |
| Connecticut | 468 | 14.0 |
| Detroit | 638 | 19.1 |
| Hawaii | 101 | 3.0 |
| Iowa | 441 | 13.2 |
| New Mexico | 113 | 3.4 |
| Seattle | 359 | 10.8 |
| Utah | 194 | 5.8 |
| Atlanta | 218 | 6.5 |
| San Jose | 144 | 4.3 |
| Los Angeles | 500 | 15.0 |
| AJCC* stage | ||
| I | 549 | 16.4 |
| II | 2183 | 65.3 |
| III | 609 | 18.2 |
| Positive lymph nodes, No. | ||
| 0 | 914 | 27.4 |
| 1–3 | 1088 | 32.6 |
| 4–9 | 660 | 19.8 |
| ≥10 | 379 | 11.3 |
| Unknown | 300 | 9.0 |
| Tumor size, cm | ||
| 0–2.0 | 1399 | 41.9 |
| 2.1–5.0 | 1327 | 39.7 |
| >5 | 505 | 15.1 |
| Unknown | 110 | 3.3 |
| Estrogen receptor status | ||
| Negative | 1185 | 35.5 |
| Positive | 1665 | 49.8 |
| Unknown | 491 | 14.7 |
| Tumor grade | ||
| Low | 234 | 7.0 |
| Intermediate | 1029 | 30.8 |
| High | 1716 | 51.4 |
| Unknown | 362 | 10.8 |
| Surgery | ||
| Breast conserving | 1143 | 34.2 |
| Mastectomy | 2198 | 65.8 |
| Received taxane | 390 | 11.7 |
*
Patients were identified through the Surveillance, Epidemiology and End Results (SEER)–Medicare linked database. All patients were diagnosed with Stage I–III Breast Cancer in April 1994 through December 1999 and received definitive surgery and chemotherapy within 1 year of diagnosis. AJCC = American Joint Committee on Cancer (14).
†
Percentage of adults in the census tract with less than 12 years of education.
‡
Percentage of census tracts residents living below poverty.