Table 2. Multivariable analysis of receiving any chemotherapy versus no chemotherapy, Stage I–III breast cancer patients, Kaiser Permanente Northern California (KPNC), 2004–2007 (N = 6004).
| Odds ratio | 95 % CI | |
|---|---|---|
| Age (years) | ||
| ≤39 | 4.45 | 2.73–7.26 |
| 40–49 | 2.27 | 1.81–2.86 |
| 50–59 | 1.0 | |
| 60–69 | 0.39 | 0.32–0.48 |
| ≥70 | 0.05 | 0.04–0.07 |
| Race, socio-economic status (SES) | ||
| High SES Non-Hispanic (NH) White | 1.0 | |
| High SES Hispanic | 1.25 | 0.89–1.75 |
| High SES NH American Indian, Alaskan Native, other, or unknown (AIAN | 0.48 | 0.16–1.47 |
| High SES NH Asian or Pacific Islander (API | 0.92 | 0.70–1.21 |
| High SES NH Black | 1.08 | 0.67–1.74 |
| Low SES NH White | 0.84 | 0.68–1.03 |
| Low SES Hispanic | 1.06 | 0.73–1.52 |
| Low SES NH AIAN | 0.65 | 0.23–1.86 |
| Low SES API | 0.98 | 0.64–1.48 |
| Low SES NH Black | 0.98 | 0.67–1.44 |
| Marital status | ||
| Married | 1.0 | |
| Unmarried (single, separated, divorced, widowed | 0.80 | 0.68–0.95 |
| Unknown | 0.51 | 0.22–1.23 |
| Tumor size (cm) | ||
| <1 cm | 0.24 | 0.19–0.31 |
| 1 to <2 | 1.0 | |
| 2 to <3 | 2.14 | 1.75–2.61 |
| 3 to <4 | 3.02 | 2.26–4.05 |
| 4 to <5 | 4.27 | 2.74–6.64 |
| ≥5 | 2.89 | 1.77–4.72 |
| Microscopic foci, diffuse, or unknown | 0.17 | 0.10–0.28 |
| Lymph node involvement | ||
| Negative or unknown | 1.0 | |
| Positive | 11.3 | 9.29–13.6 |
| Grade | ||
| Grade I (well differentiated) | 1.0 | |
| Grade II (moderately differentiated) | 2.06 | 1.66–2.55 |
| Grade III (poorly or undifferentiated | 3.53 | 2.77–4.49 |
| Unknown | 1.49 | 1.07–2.09 |
| Estrogen, progesterone receptors (ER/PR) and endocrine therapya | ||
| ER/PR-positive, no endocrine therapy | 1.0 | |
| ER/PR-negative, no endocrine therapy | 6.94 | 4.89–9.86 |
| ER/PR-unknown, no endocrine therapy | 0.20 | 0.06–0.75 |
| ER/PR-positive, received endocrine therapy | 2.31 | 1.71–3.13 |
| HER2 | ||
| Negative | 1.0 | |
| Positive | 2.71 | 2.10–3.51 |
| Unknown or borderline | 1.38 | 1.14–1.67 |
| Diabetes | ||
| No | 1.0 | |
| Yes | 0.71 | 0.54–0.94 |
| Neuropathy | ||
| No | 1.0 | |
| Yes | 0.53 | 0.31–0.89 |
| Heart disease | ||
| No | 1.0 | |
| Yes | 0.38 | 0.26–0.56 |
| Modified Charlson Comorbidity Indexb | ||
| 0 | 1.0 | |
| 1 | 1.12 | 0.86–1.45 |
| 2 | 1.10 | 0.55–2.20 |
| ≥3 | 0.03 | 0.01–0.18 |
| Distance to reporting KPNC facility (miles) | ||
| <5 | 1.0 | |
| 5 to <10 | 1.05 | 0.87–1.27 |
| 10 to <15 | 0.93 | 0.73–1.20 |
| 15 to <20 | 1.31 | 0.99–1.74 |
| 20 to <30 | 0.89 | 0.65–1.22 |
| 30 to <40 | 0.57 | 0.33–0.97 |
| ≥40 | 1.15 | 0.63–2.09 |
| Surgery type | ||
| Breast conserving surgery | 1.0 | |
| Mastectomy | 1.41 | 1.19–1.67 |
| None or other | 0.72 | 0.37–1.39 |
| Year of diagnosis, per year | 1.03 | 0.96–1.12 |
a
Excluded ER/PR-negative or unknown, received endocrine therapy, given the high probability that these groups reflect errors in data collection, since endocrine therapy is not clinically indicated in this setting
b
This Charlson Comorbidity Index excluded heart disease, diabetes and neuropathy, which were evaluated separately