Table 3. Multivariable Logistic Regression: Association of Selected Factors With Receipt of RT by Age Group and Overall.
| Category | Age 18-39 y (n = 1280) | Age 40-64 y (n = 3937) | Age ≥65 y (n = 3736) | All (N = 8953) | ||||
|---|---|---|---|---|---|---|---|---|
| OR (95% CI) | P value | OR (95% CI) | P value | OR (95% CI) | P value | OR (95% CI) | P value | |
| Sex | ||||||||
| Male | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Female | 0.81 (0.64-1.03) | .09 | 1.06 (0.92-1.22) | .42 | 0.95 (0.83-1.09) | .47 | 0.98 (0.89-1.07) | .62 |
| Race/ethnicity | ||||||||
| White non-Hispanic | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| White Hispanic | 0.53 (0.36-0.78) | .002 | 0.73 (0.54-0.98) | .04 | 0.80 (0.55-1.17) | .25 | 0.71 (0.58-0.87) | <.001 |
| Black | 0.80 (0.56-1.15) | .23 | 0.86 (0.68-1.08) | .20 | 1.14 (0.86-1.51) | .36 | 0.95 (0.81,1.11) | .51 |
| Other or unknowna | 0.68 (0.46-1.00) | .05 | 0.83 (0.65-1.06) | .14 | 0.98 (0.78-1.25) | .89 | 0.87 (0.74-1.01) | .07 |
| Insurance status | ||||||||
| Not insured | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Private Insurance | 1.80 (1.19-2.72) | .006 | 1.60 (1.20-2.15) | .002 | 2.00 (0.79-5.04) | .14 | 1.68 (1.34-2.11) | .001 |
| Medicaid | 1.15 (0.71-1.84) | .57 | 1.28 (0.87-1.86) | .21 | 1.44 (0.50-4.14) | .49 | 1.22 (0.92-1.60) | .17 |
| Medicare | 1.30 (0.59-2.84) | .51 | 0.99 (0.68-1.45) | .97 | 1.56 (0.63-3.86) | .34 | 1.19 (0.92-1.55) | .18 |
| Other or unknown | 3.59 (1.66-7.78) | .001 | 1.38 (0.88-2.16) | .16 | 2.99 (1.05-8.55) | .04 | 1.92 (1.36-2.70) | <.001 |
| Median income in patient’s zip code in 2012, $ | ||||||||
| >63 000 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 48 000-62 999 | 1.01 (0.69-1.46) | .98 | 1.00 (0.81-1.23) | .96 | 0.91 (0.74-1.12) | .36 | 0.96 (0.84-1.10) | .58 |
| 38 000-47 999 | 0.76 (0.50-1.17) | .22 | 1.07 (0.83-1.37) | .61 | 0.85 (0.67-1.09) | .20 | 0.92 (0.79-1.08) | .33 |
| <38 000 | 0.68 (0.41-1.13) | .14 | 0.97 (0.72-1.31) | .84 | 0.76 (0.56-1.03) | .07 | 0.83 (0.68-1.01) | .06 |
| Unknown | 1.05 (0.10-11.42) | .97 | 0.72 (0.18-2.93) | .65 | 1.00 (0.06-16.21) | >.99 | 0.92 (0.30-2.87) | .89 |
| Non–high school graduates, % of population in patient’s zip code | ||||||||
| <7 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 7-12.9 | 1.38 (0.96-1.98) | .09 | 0.96 (0.78-1.17) | .66 | 0.95 (0.78-1.16) | .61 | 1.00 (0.88-1.14) | .97 |
| 13-20.9 | 1.40 (0.91-2.15) | .13 | 0.96 (0.75-1.23) | .75 | 0.95 (0.75-1.20) | .68\ | 1.02 (0.87-1.19) | .85 |
| ≥21 | 1.23 (0.74-2.03) | .42 | 0.90 (0.67-1.20) | .47 | 0.81 (0.61-1.09) | .17 | 0.90 (0.75-1.09) | .30 |
| Unknown | 1.20 (0.01-229.42) | .95 | 1.30 (0.08-20.20) | .85 | 0.26 (0.01-10.57) | .47 | 0.70 (0.10-4.72) | .71 |
| Living location | ||||||||
| Metropolitanb | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Smaller metropolitanb | 1.00 (0.73-1.37) | .99 | 1.08 (0.90-1.30) | .43 | 1.33 (1.11-1.59) | .002 | 1.17 (1.04-1.32) | .008 |
| Urban | 1.15 (0.74-1.79) | .53 | 1.31 (1.02-1.69) | .04 | 1.92 (1.49-2.47) | .001 | 1.51 (1.29-1.79) | .001 |
| Rural | 0.78 (0.22-2.84) | .71 | 1.52 (0.86-2.67) | .15 | 1.77 (1.02-3.08) | .04 | 1.55 (1.06-2.25) | .02 |
| Unknown | 1.40 (0.61-3.21) | .43 | 1.44 (0.87-2.39) | .16 | 0.95 (0.62-1.48) | .84 | 1.17 (0.86-1.58) | .31 |
| Distance to reporting facility, miles | ||||||||
| ≤10 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 11-20 | 0.61 (0.43-0.87) | .007 | 0.76 (0.61-0.93) | .009 | 0.75 (0.61-0.92) | .005 | 0.73 (0.64-0.84) | .001 |
| 21-50 | 0.59 (0.41-0.84) | .004 | 0.61 (0.50-0.75) | .001 | 0.78 (0.64-0.96) | .02 | 0.68 (0.60-0.78) | .001 |
| >50 | 0.39 (0.27-0.56) | .001 | 0.38 (0.31-0.47) | .001 | 0.43 (0.35-0.53) | .001 | 0.40 (0.35-0.46) | .001 |
| Unknown | 0.32 (0.00-42.37) | .65 | 0.53 (0.06-5.02) | .58 | 2.02 (0.16-26.18) | .59 | 0.76 (0.16-3.63) | .73 |
| Comorbidities, No. | ||||||||
| 0 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 1 | 1.20 (0.68-2.11) | .53 | 0.88 (0.71-1.09) | .23 | 0.78 (0.65-0.92) | .003 | 0.82 (0.72-0.93) | .003 |
| 2 | 0.60 (0.08-4.32) | .62 | 0.71 (0.45-1.10) | .12 | 0.76 (0.56-1.04) | .08 | 0.74 (0.58-0.95) | .02 |
| Transition in care | ||||||||
| No | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Yes | 1.37 (0.97-1.93) | .07 | 1.45 (1.18-1.79) | <.001 | 1.87 (1.53-2.28) | .001 | 1.61 (1.41-1.84) | .001 |
| Unknown | 0.83 (0.57-1.21) | .34 | 1.08 (0.86-1.35) | .53 | 1.16 (0.94-1.44) | .17 | 1.07 (0.93-1.23) | .34 |
| Primary site | ||||||||
| Upper limb | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Lower limb | 1.03 (0.78-1.35) | .86 | 0.93 (0.78-1.10) | .38 | 0.84 (0.71-0.99) | .04 | 0.91 (0.81-1.01) | .07 |
| Grade | ||||||||
| MD | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| PD | 1.03 (0.73-1.44) | .88 | 1.16 (0.93-1.44) | .18 | 1.20 (0.95-1.52) | .13 | 1.14 (0.99-1.31) | .07 |
| UD | 0.87 (0.61-1.25) | .46 | 1.22 (0.97-1.53) | .09 | 1.29 (1.01-1.64) | .04 | 1.17 (1.01-1.36) | .04 |
| Tumor size, cm | ||||||||
| ≤5.00 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 5.01-10.00 | 1.44 (0.97-2.14) | .07 | 1.28 (1.02-1.62) | .03 | 1.25 (1.00-1.56) | .05 | 1.30 (1.12-1.51) | <.001 |
| 10.01-15.00 | 1.60 (1.02-2.52) | .04 | 1.21 (0.93-1.58) | .16 | 1.49 (1.14-1.94) | .004 | 1.39 (1.17-1.65) | <.001 |
| >15.00 | 1.14 (0.69-1.86) | .61 | 1.07 (0.82-1.40) | .64 | 1.09 (0.83-1.42) | .53 | 1.10 (0.92-1.31) | .29 |
| Clinical tumor stage | ||||||||
| I | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| II | 1.25 (0.81-1.91) | .31 | 1.66 (1.30-2.13) | .001 | 1.32 (1.04-1.69) | .02 | 1.45 (1.24-1.71) | .001 |
| Unknown | 1.10 (0.74-1.64) | .65 | 1.24 (0.98-1.56) | .07 | 0.98 (0.78-1.24) | .86 | 1.11 (0.95-1.29) | .19 |
| Depth of extension | ||||||||
| Superficial | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Deep | 1.86 (1.38-2.51) | .001 | 1.46 (1.23-1.74) | .001 | 1.21 (1.02-1.43) | .03 | 1.37 (1.22-1.53) | .001 |
| Unknown | 1.42 (0.92-2.21) | .12 | 1.06 (0.81-1.39) | .68 | 0.92 (0.70-1.20) | .53 | 1.03 (0.86-1.22) | .77 |
| Surgical margin | ||||||||
| Negative | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Positive | 1.43 (0.93-2.22) | .11 | 1.31 (1.04-1.64) | .02 | 1.27 (1.06-1.53) | .01 | 1.28 (1.12-1.47) | <.001 |
| Unknown | 0.69 (0.38-1.25) | .23 | 1.24 (0.82-1.87) | .31 | 1.08 (0.75-1.55) | .69 | 1.07 (0.84-1.36) | .60 |
| Age, y | ||||||||
| 18-39 | NA | NA | NA | NA | NA | NA | 1 [Reference] | NA |
| 40-64 | NA | NA | NA | NA | NA | NA | 1.40 (1.22-1.61) | .001 |
| ≥65 | NA | NA | NA | NA | NA | NA | 1.33 (1.10-1.61) | .003 |
Abbreviations: MD, moderately differentiated; NA, not applicable; OR, odds ratio; PD, poorly differentiated; RT, radiation therapy; UD, undifferentiated.
a
Other races/ethnicities included American Indian, Aleutian, or Eskimo; Chinese; Japanese; Filipino; Hawaiian; Korean; Vietnamese; Laotian; Hmong; Kampuchean; Thai; Asian Indian or Pakistani, not otherwise specified; Asian Indian; Pakistani; Micronesian, not otherwise specified; Chamorran; Guamanian, not otherwise specified; Polynesian, not otherwise specified; Tahitian, Samoan, Tongan, Melanesian, not otherwise specified; Fiji Islander; New Guinean; other Asian, including Asian, not otherwise specified, and Oriental, not otherwise specified; and Pacific Islander, not otherwise specified.
b
Metropolitan was defined as having a population of 250 000 or greater; smaller metropolitan, 20 000 to less than 250 000.