Table 2.
Multivariate Analysis of Predictors of Multiagent Chemotherapy Receipt by Patient/Oncologist Characteristics for Oxaliplatin Use (and/or irinotecan use for stage IV)*
| Characteristic | Stage III (n = 1,178)† |
Stage IV (n = 781)† |
||
|---|---|---|---|---|
| OR | 95% CI | OR | 95% CI | |
| Patient | ||||
| Total patients | ||||
| No. | 432 | 357 | ||
| % | 36.7 | 45.7 | ||
| Age at diagnosis, years | ||||
| 65-69 | Referent | Referent | ||
| 70-74 | 0.49 | 0.32 to 0.76 | 0.69 | 0.41 to 1.16 |
| 75-79 | 0.27 | 0.18 to 0.42 | 0.54 | 0.33 to 0.91 |
| 80-84 | 0.07 | 0.04 to 0.11 | 0.21 | 0.12 to 0.35 |
| ≥ 85 | 0.0045 | 0.001 to 0.01 | 0.03 | 0.01 to 0.08 |
| Sex | ||||
| Male | Referent | Referent | ||
| Female | 0.80 | 0.58 to 1.10 | 0.70 | 0.49 to 1.01 |
| Race | ||||
| White | Referent | Referent | ||
| Black | 0.51 | 0.28 to 0.94 | 1.01 | 0.52 to 1.96 |
| Hispanic | 0.23 | 0.02 to 2.46 | 1.36 | 0.43 to 4.26 |
| Other | 0.55 | 0.30 to 1.03 | 1.07 | 0.47 to 2.46 |
| Marital status | ||||
| Married | Referent | Referent | ||
| Single/divorced | 0.45 | 0.32 to 0.62 | 0.51 | 0.35 to 0.73 |
| Unknown | 0.52 | 0.26 to 1.04 | 0.63 | 0.26 to 1.52 |
| Urban/rural location | ||||
| Urban | 2.27 | 1.31 to 3.93 | 0.62 | 0.34 to 1.14 |
| SES, quintile | ||||
| Lowest | Referent | Referent | ||
| Second | 0.71 | 0.41 to 1.25 | 0.73 | 0.35 to 1.50 |
| Third | 0.68 | 0.38 to 1.20 | 1.00 | 0.48 to 2.09 |
| Fourth | 0.99 | 0.57 to 1.73 | 0.93 | 0.44 to 1.96 |
| Highest | 0.89 | 0.50 to 1.57 | 1.09 | 0.51 to 2.33 |
| Clinical | ||||
| Grade | ||||
| Well differentiated | Referent | Referent | ||
| Moderately differentiated | 2.40 | 1.25 to 4.58 | 0.83 | 0.30 to 2.33 |
| Poorly differentiated | 2.74 | 1.40 to 5.39 | 0.72 | 0.25 to 2.08 |
| Undifferentiated | 1.29 | 0.41 to 4.06 | 0.28 | 0.06 to 1.37 |
| Unknown | 1.29 | 0.39 to 4.30 | 0.34 | 0.12 to 0.99 |
| No. of comorbidities | ||||
| 0 | Referent | Referent | ||
| 1 | 0.55 | 0.40 to 0.78 | 0.66 | 0.45 to 0.98 |
| ≥ 2 | 0.36 | 0.23 to 0.58 | 0.49 | 0.29 to 0.81 |
| Hypertension | ||||
| No | Referent | Referent | ||
| Yes | 1.09 | 0.78 to 1.51 | 0.95 | 0.65 to 1.40 |
| Oncologist | ||||
| Sex | ||||
| Male | Referent | Referent | ||
| Female | 1.08 | 0.75 to 1.55 | 1.04 | 0.68 to 1.59 |
| US trained | ||||
| No | Referent | Referent | ||
| Yes | 0.75 | 0.55 to 1.05 | 1.45 | 1.02 to 2.06 |
| Date of graduation | ||||
| < 1975 | Referent | Referent | ||
| ≥ 1975 | 1.65 | 1.11 to 2.45 | 2.43 | 1.47 to 4.01 |
| Type of practice | ||||
| Nonprivate | Referent | Referent | ||
| Private | 1.30 | 0.92 to 1.84 | 0.88 | 0.60 to 1.28 |
| No. of patients in cohort | ||||
| 1 | Referent | Referent | ||
| ≥ 2 | 1.13 | 0.83 to 1.55 | 1.60 | 1.14 to 2.25 |
Abbreviations: OR, odds ratio; SEER, Surveillance, Epidemiology, and End Results; SES, socioeconomic status.
Patients > 65 years of age diagnosed with histologically confirmed colon cancer in the SEER-Medicare database who saw an oncologist between September 1, 2004, and December 31, 2005; for patients with stage IV disease, between January 1, 2005, and December 31, 2005.
Comparison for patients with stage III disease is between patients who received oxaliplatin and those who received no chemotherapy; comparison for patients with stage IV/recurrent disease is between those who received either oxaliplatin and/or irinotecan and those who received no chemotherapy.