Table 2.
Regression results showing predictors of second- and subsequent-line treatments in patients with metastatic colon cancer in the SEER-Medicare dataset
| First-line treatment | Second-line treatment | Subsequent-line treatment | ||||
|---|---|---|---|---|---|---|
| Risk ratio | 95% confidence interval | Risk ratio | 95% confidence interval | Risk ratio | 95% confidence interval | |
| Age group | ||||||
| 65–69 | Reference | Reference | Reference | |||
| 70–74 | 0.90*** | (0.85, 0.95) | 0.87** | (0.77, 0.969) | 0.790 | (0.58, 1.08) |
| 75–79 | 0.79*** | (0.74, 0.84) | 0.70*** | (0.62, 0.783) | 0.643*** | (0.47, 0.89) |
| >80 | 0.43*** | (0.40, 0.46) | 0.29*** | (0.25, 0.335) | 0.288*** | (0.20, 0.42) |
| Race/ethnicity | ||||||
| White, non-Hispanic | Reference | Reference | Reference | |||
| Another minority group | 0.91 | (0.80, 1.03) | 0.87 | (0.69, 1.09) | 1.05 | (0.58, 1.91) |
| African American | 0.89** | (0.82, 0.98) | 0.79*** | (0.66, 0.93) | 0.57** | (0.35, 0.92) |
| Hispanic | 0.99 | (0.88, 1.11) | 0.84 | (0.67, 1.06) | 1.00 | (0.57, 1.75) |
| Gender | ||||||
| Male | Reference | Reference | Reference | |||
| Female | 1.03 | (0.98, 1.08) | 1.02 | (0.93, 1.11) | 1.05 | (0.83, 1.34) |
| Marital status | ||||||
| Not married | Reference | Reference | Reference | |||
| Married | 1.29*** | (1.22, 1.36) | 1.46*** | (1.32, 1.61) | 1.20 | (0.93, 1.55) |
| SEER-registry area | ||||||
| Connecticut | Reference | Reference | Reference | |||
| Detroit | 0.81*** | (0.72, 0.91) | 0.75*** | (0.61, 0.92) | 1.04 | (0.62, 1.77) |
| Iowa | 0.84*** | (0.74, 0.94) | 0.66*** | (0.54, 0.82) | 0.58* | (0.31, 1.08) |
| Seattle | 0.85** | (0.75, 0.97) | 0.71** | (0.57, 0.90) | 0.88 | (0.48, 1.60) |
| Los Angeles | 0.99 | (0.88, 1.11) | 0.95 | (0.77, 1.17) | 0.98 | (0.54, 1.75) |
| Greater California | 0.83*** | (0.75, 0.92) | 0.67*** | (0.56, 0.80) | 0.76 | (0.47, 1.23) |
| Kentucky | 0.81*** | (0.72, 0.90) | 0.54*** | (0.43, 0.67) | 0.44** | (0.24, 0.84) |
| Louisiana | 0.76*** | (0.67, 0.87) | 0.64*** | (0.51, 0.80) | 0.67 | (0.36, 1.25) |
| New Jersey | 0.88** | (0.79, 0.97) | 0.79*** | (0.67, 0.94) | 1.09 | (0.69, 1.72) |
| Other registry areas | 0.83*** | (0.75, 0.92) | 0.70*** | (0.58, 0.84) | 0.50** | (0.29, 0.86) |
| State buy-in during diagnosis year | ||||||
| None | Reference | Reference | Reference | |||
| 1–6months | 0.45*** | (0.36, 0.55) | 0.37*** | (0.25, 0.56) | 0.18** | (0.04, 0.70) |
| 7–12months | 0.88** | (0.81, 0.96) | 0.88 | (0.74, 1.03) | 0.90 | (0.61, 1.35) |
| Charlson comorbidity index | ||||||
| 0 | Reference | Reference | Reference | |||
| 1 | 1.00 | (0.94, 1.06) | 0.95 | (0.85, 1.06) | 1.07 | (0.82, 1.41) |
| 2+ | 0.82*** | (0.75, 0.89) | 0.76*** | (0.65, 0.89) | 0.62** | (0.40, 0.96) |
| Poor performance indicators | ||||||
| No | Reference | Reference | Reference | |||
| Yes | 0.78*** | (0.71, 0.86) | 0.64*** | (0.53, 0.78) | 0.51** | (0.30, 0.87) |
| Surgery of PS | ||||||
| No | Reference | Reference | Reference | |||
| Yes | 1.65*** | (1.55, 1.76) | 2.05*** | (1.82, 2.30) | 2.13*** | (1.58, 2.88) |
| Surgery of RDS | ||||||
| No | Reference | Reference | Reference | |||
| Liver metastases surgery | 1.17*** | (1.10, 1.25) | 1.11* | (0.98, 1.26) | 0.94 | (0.66, 1.35) |
| Other surgery | 1.03 | (0.92, 1.14) | 0.88 | (0.71, 1.09) | 1.19 | (0.66, 1.35) |
SEER, Surveillance, Epidemiology and End Results; PS, primary site; RDS, regional or distal site. Other registry areas: Atlanta, Hawaii, New Mexico, Rural Georgia, San Francisco, San Jose, Utah.
Note: ***, **, and * represented 1%, 5%, and 10% significance levels respectively.