Table 2.
Proportion of stages II and III colon cancer patients who received adjuvant chemotherapy by stage at diagnosis (n = 3757)*
| Characteristics | Proportion of patients receiving chemotherapy | |||
|---|---|---|---|---|
| Stage II (n = 1908) | Stage III (n = 1849) | |||
| wt % | 95 % CI | wt % | 95% CI | |
| Overall | 28.7 | 25.4 to 32.3 | 65.4 | 61.8 to 68.9 |
| Year of diagnosis | ||||
| 1990/1991 | 22.5 | 19.0 to 26.4 | 56.3 | 51.0 to 61.4 |
| 1995 | 27.9 | 21.2 to 35.6 | 59.5 | 48.6 to 69.6 |
| 2000 | 33.5 | 24.4 to 44.2 | 65.3 | 56.2 to 73.4 |
| 2005 | 32.1 | 24.8 to 40.5 | 72.4 | 65.1 to 78.7 |
| 2010 | 29.3 | 21.8 to 38.2 | 66.4 | 58.2 to 73.7 |
| Age at diagnosis, y | ||||
| <55 | 59.5 | 48.6 to 69.5 | 84.5 | 78.6 to 89.0 |
| 55–64 | 46.2 | 38.4 to 54.2 | 84.9 | 79.3 to 89.2 |
| 65–74 | 29.9 | 23.9 to 36.6 | 72.9 | 65.4 to 79.3 |
| 75–79 | 17.3 | 11.3 to 25.4 | 63.0 | 54.0 to 71.2 |
| ≥80 | 5.8 | 3.6 to 9.0 | 30.3 | 21.9 to 40.3 |
| Race/ethnicity | ||||
| White non-Hispanic | 28.1 | 23.9 to 32.6 | 65.5 | 60.8 to 70.0 |
| Black non-Hispanic | 28.8 | 23.5 to 34.8 | 60.8 | 54.8 to 66.6 |
| Hispanic | 34.4 | 27.3 to 42.3 | 65.0 | 54.7 to 74.1 |
| Other | 29.8 | 23.0 to 37.6 | 71.0 | 62.1 to 78.6 |
| Health insurance | ||||
| Private/HMO/VA/Other | 31.2 | 26.9 to 35.7 | 67.0 | 62.7 to 71.1 |
| Medicaid | 24.2 | 15.8 to 35.2 | 61.4 | 51.8 to 70.2 |
| Medicare | 18.5 | 12.6 to 26.3 | 57.9 | 47.7 to 67.5 |
| None | 43.3 | 28.0 to 60.0 | 73.6 | 55.2 to 86.3 |
| Unknown | 39.9 | 19.8 to 64.2 | 76.0 | 50.6 to 90.7 |
| Comorbidity score | ||||
| 0 | 31.5 | 27.4 to 36.0 | 68.5 | 64.3 to 72.4 |
| 1 | 23.1 | 17.2 to 30.4 | 64.0 | 56.5 to 70.9 |
| ≥2 | 16.8 | 7.2 to 34.2 | 33.6 | 22.0 to 47.6 |
| Tumor extent | ||||
| T1-2 | NA | NA | 76.9 | 66.9 to 84.5 |
| T3 | 24.8 | 21.7 to 28.3 | 65.4 | 61.4 to 69.2 |
| T4 | 53.6 | 41.7 to 65.2 | 58.0 | 47.6 to 67.8 |
| Histologic grade | ||||
| Well/moderately differentiated | 28.7 | 25.4 to 32.3 | 67.1 | 62.8 to 71.2 |
| Poorly/undifferentiated | 27.3 | 20.2 to 35.7 | 61.2 | 53.7 to 68.2 |
| Unknown | 37.6 | 24.2 to 53.2 | 65.0 | 49.8 to 77.6 |
| Positive margins at surgery | ||||
| Yes | 49.1 | 27.7 to 70.8 | 53.8 | 36.9 to 69.8 |
| No | 28.3 | 24.7 to 32.2 | 66.5 | 62.8 to 69.9 |
| Unknown | 24.7 | 17.4 to 33.9 | 62.2 | 47.1 to 75.3 |
* Proportions weighted by sampling fraction. Table excludes patients who did not undergo cancer-directed surgery (n = 20) or with missing or unknown chemotherapy agents (n = 82); patients who received preoperative chemotherapy (n = 6) are included. CI = confidence interval; NA = not applicable; wt = weighted.