Table 4.
Predictors of receipt of >10 fractions of RT among patients who received conventional RT
| Univariable |
Multivariable |
|||||||
|---|---|---|---|---|---|---|---|---|
| Predictors | >10 fractions | ≤10 fractions | OR | 95% CI | P-value | OR | 95% CI | P-value |
| Demographic | ||||||||
| Age at time of diagnosis (years) | ||||||||
| 65-69 | 50% | 50% | ref | < .01 | .02 | |||
| 70-74 | 49% | 51% | 0.97 | 0.90-1.04 | 1.02 | 0.95-1.10 | ||
| 75-79 | 47% | 53% | 0.89 | 0.83-0.96 | 0.98 | 0.91-1.06 | ||
| >80 | 47% | 53% | 0.89 | 0.82-0.96 | 1.13 | 1.04-1.23 | ||
| Sex | ||||||||
| Female | 48% | 52% | ref | .70 | .63 | |||
| Male | 49% | 51% | 1.01 | 0.96-1.07 | 0.99 | 0.93-1.05 | ||
| Race | ||||||||
| White | 49% | 51% | ref | .04 | .16 | |||
| Black | 46% | 54% | 0.88 | 0.80-0.97 | 0.92 | 0.81-1.04 | ||
| Asian/Pacific Islander | 48% | 52% | 0.93 | 0.82-1.06 | 0.97 | 0.66-1.44 | ||
| Other | 48% | 52% | 1.25 | 0.81-1.93 | 1.51 | 1.00-2.30 | ||
| Marital status | ||||||||
| Not married | 47% | 53% | ref | < .01 | .46 | |||
| Married | 49% | 51% | 1.10 | 1.04-1.16 | 1.02 | 0.97-1.08 | ||
| Diagnosis year | ||||||||
| 2004-2005 | 48% | 52% | ref | .65 | .68 | |||
| 2006-2007 | 48% | 52% | 1.00 | 0.93-1.08 | 1.03 | 0.97-1.10 | ||
| 2008-2009 | 48% | 52% | 1.02 | 0.94-1.10 | 1.02 | 0.94-1.10 | ||
| 2010-2011 | 49% | 51% | 1.05 | 0.97-1.13 | 1.05 | 0.96-1.14 | ||
| Median income quartile (percentile)* | ||||||||
| ≤25th | 49% | 51% | ref | .11 | .23 | |||
| 25th-50th | 49% | 51% | 1.02 | 0.94-1.10 | 1.07 | 0.94-1.21 | ||
| 50th-75th | 47% | 53% | 0.93 | 0.87-1.01 | 0.96 | 0.85-1.09 | ||
| >75th | 48% | 52% | 0.96 | 0.89-1.03 | 1.03 | 0.91-1.17 | ||
| Clinical and treatment | ||||||||
| Modified Charlson comorbidity score† | ||||||||
| 0 | 49% | 51% | ref | .30 | .57 | |||
| 1 | 49% | 51% | 1.00 | 0.94-1.07 | 1.00 | 0.93-1.08 | ||
| 2 | 47% | 53% | 0.94 | 0.86-1.04 | 0.95 | 0.85-1.07 | ||
| 3 + | 47% | 53% | 0.93 | 0.84-1.02 | 0.95 | 0.87-1.04 | ||
| Chemotherapy‡ | ||||||||
| No | 39% | 61% | ref | < .01 | < .01 | |||
| Yes | 54% | 46% | 1.79 | 1.69-1.89 | 1.74 | 1.61-1.88 | ||
| Hospice services‡ | ||||||||
| No | 52% | 48% | ref | < .01 | < .01 | |||
| Yes | 44% | 56% | 0.73 | 0.69-0.77 | 0.77 | 0.73-0.82 | ||
| Regional and health care services | ||||||||
| SEER region | ||||||||
| Northeast | 43% | 57% | ref | .09 | .07 | |||
| South | 50% | 50% | 1.34 | 1.24-1.45 | 1.19 | 1.02-1.39 | ||
| Midwest | 49% | 51% | 1.27 | 1.15-1.39 | 1.23 | 1.04-1.46 | ||
| West | 49% | 51% | 1.29 | 1.19-1.39 | 1.13 | 0.97-1.33 | ||
| Living in urban area | ||||||||
| No | 50% | 50% | ref | .09 | .40 | |||
| Yes | 48% | 52% | 0.93 | 0.86-1.01 | 1.06 | 0.93-1.20 | ||
| Radiation oncologist density§ | ||||||||
| Lowest tertile | 50% | 50% | ref | < .01 | .63 | |||
| Middle tertile | 47% | 53% | 0.90 | 0.84-0.96 | 0.96 | 0.85-1.09 | ||
| Highest tertile | 48% | 52% | 0.92 | 0.86-0.99 | 1.01 | 0.90-1.13 | ||
| RT facility type | ||||||||
| Hospital-based | 44% | 56% | ref | < .01 | < .01 | |||
| Freestanding | 58% | 43% | 1.74 | 1.65-1.84 | 1.74 | 1.60-1.89 | ||
CI, confidence interval; OR, odds ratio; ref, reference group; RT, radiation therapy; SEER, Surveillance, Epidemiology and End Results.
*
By ZIP code.
†
Measured using the Klabunde modification.
‡
Within 1 year of diagnosis.
§
Number of radiation oncologists (per 100,000 population) practicing within each patient's county of residence, divided into top (>1.5), middle (1-1.5), and bottom (<1) tertiles.