Table 2. Univariable Logistic Regression: Association of Selected Factors With Receipt of RT .
| Factor | 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 | 0.78 (0.62-0.97) | .03 | 1.05 (0.91-1.20) | .52 | 0.92 (0.80-1.05) | .21 | 0.93 (0.86-1.02) | .12 |
| Race/ethnicity | ||||||||
| White Non-Hispanic | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| White Hispanic | 0.50 (0.36-0.70) | .001 | 0.80 (0.61-1.05) | .10 | 0.77 (0.54-1.10) | .15 | 0.69 (0.58-0.83) | .001 |
| Black | 0.74 (0.54-1.02) | .07 | 0.90 (0.73-1.11) | .34 | 1.07 (0.82-1.39) | .64 | 0.93 (0.80-1.07) | .30 |
| Other or unknowna | 0.72 (0.50-1.04) | .08 | 0.89 (0.70-1.12) | .32 | 1.03 (0.82-1.30) | .79 | 0.91 (0.78-1.05) | .21 |
| Insurance status | ||||||||
| Not insured | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Private insurance | 2.10 (1.44-3.06) | <.001 | 1.54 (1.17-2.04) | .002 | 2.45 (1.02-5.91) | .045 | 1.83 (1.48-2.27) | .001 |
| Medicaid | 1.28 (0.82-2.01) | .28 | 1.21 (0.84-1.74) | .31 | 1.70 (0.62-4.67) | .30 | 1.21 (0.92-1.58) | .17 |
| Medicare | 1.37 (0.66-2.83) | .40 | 0.97 (0.67-1.39) | .85 | 1.83 (0.77-4.32) | .17 | 1.35 (1.09-1.67) | .006 |
| Other or unknown | 2.82 (1.37-5.79) | .005 | 1.32 (0.86-2.04) | .20 | 3.36 (1.23-9.13) | .02 | 1.92 (1.38-2.67) | <.001 |
| Median income in patient’s zip code in 2012, $ | ||||||||
| <38 000 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 48 000-62 999 | 1.02 (0.76-1.37) | .90 | 0.91 (0.76-1.09) | .32 | 0.92 (0.77-1.10) | .35 | 0.92 (0.82-1.03) | .17 |
| 38 000-47 999 | 0.76 (0.56-1.04) | .09 | 0.93 (0.77-1.12) | .44 | 0.88 (0.73-1.06) | .17 | 0.88 (0.78-0.99) | .03 |
| ≥63 000 | 0.58 (0.42-0.81) | .001 | 0.82 (0.67-1.00) | .045 | 0.76 (0.62-0.93) | .008 | 0.74 (0.65-0.85) | .001 |
| Unknown | 1.08 (0.39-2.98) | .88 | 1.02 (0.58-1.78) | .95 | 0.57 (0.34-0.95) | .03 | 0.78 (0.55-1.10) | .16 |
| 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 | 1.17 (0.86-1.59) | .32 | 0.91 (0.76-1.08) | .28 | 0.89 (0.74-1.06) | .18 | 0.93 (0.83-1.04) | .20 |
| 13-20.9 | 0.99 (0.72-1.38) | .97 | 0.92 (0.76-1.12) | .43 | 0.88 (0.73-1.06) | .18 | 0.91 (0.80-1.03) | .12 |
| ≥21 | 0.70 (0.50-0.98) | .04 | 0.79 (0.65-0.98) | .03 | 0.75 (0.60-0.93) | .01 | 0.76 (0.66-0.87) | .001 |
| Unknown | 1.21 (0.40-3.70) | .74 | 1.04 (0.56-1.91) | .91 | 0.56 (0.34-0.95) | .03 | 0.78 (0.54-1.12) | .18 |
| Living location | ||||||||
| Metropolitanb | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Smaller metropolitanb | 0.87 (0.67-1.12) | .28 | 0.85 (0.73-0.99) | .04 | 1.05 (0.90-1.22) | .57 | 0.92 (0.84-1.02) | .12 |
| Urban | 0.79 (0.56-1.12) | .19 | 0.85 (0.70-1.04) | .11 | 1.15 (0.95-1.41) | .16 | 0.96 (0.84-1.09) | .54s |
| Rural | 0.53 (0.16-1.76) | .30 | 0.80 (0.47-1.35) | .40 | 0.98 (0.59-1.65) | .95 | 0.86 (0.61-1.22) | .39 |
| Unknown | 1.18 (0.61-2.31) | .62 | 1.19 (0.80-1.78) | .38 | 0.76 (0.54-1.06) | .11 | 0.94 (0.74-1.19) | .62 |
| Distance to reporting facility, miles | ||||||||
| ≤10 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 11-20 | 0.74 (0.54-1.03) | .08 | 0.81 (0.67-0.99) | .04 | 0.86 (0.71-1.05) | .14 | 0.83 (0.73-0.94) | .004 |
| 21-50 | 0.82 (0.60-1.14) | .24 | 0.71 (0.59-0.86) | <.001 | 0.98 (0.81-1.18) | .82 | 0.84 (0.74-0.95) | .005 |
| >50 | 0.57 (0.43-0.76) | <.001 | 0.50 (0.42-0.60) | .001 | 0.66 (0.56-0.79) | .001 | 0.58 (0.52-0.65) | .001 |
| Unknown | 0.85 (0.27-2.64) | .78 | 0.81 (0.45-1.48) | .50 | 0.57 (0.34-0.97) | .04 | 0.69 (0.48-1.00) | .05 |
| Comorbidities, No. | ||||||||
| 0 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 1 | 1.14 (0.67-1.93) | .63 | 0.82 (0.67-1.00) | .05 | 0.78 (0.66-0.92) | .003 | 0.82 (0.72-0.92) | <.001 |
| 2 | 0.46 (0.08-2.76) | .40 | 0.64 (0.42-0.98) | .04 | 0.73 (0.54-0.98) | .04 | 0.70 (0.55-0.89) | .003 |
| Transition in care | ||||||||
| No | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Yes | 1.30 (0.95-1.78) | .10 | 1.26 (1.04-1.54) | .02 | 1.67 (1.38-2.01) | .001 | 1.44 (1.27-1.63) | .001 |
| Unknown | 0.91 (0.65-1.28) | .59 | 1.09 (0.88-1.35) | .42 | 1.19 (0.98-1.46) | .09 | 1.11 (0.97-1.27) | .12 |
| Primary site | ||||||||
| Upper limb | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Lower limb | 1.09 (0.85-1.41) | .48 | 1.06 (0.90-1.24) | .49 | 0.91 (0.78-1.06) | .23 | 1.01 (0.91-1.12) | .84 |
| Grade | ||||||||
| MD | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| PD | 1.08 (0.80-1.47) | .62 | 1.17 (0.96-1.44) | .12 | 1.21 (0.97-1.51) | .10 | 1.16 (1.02-1.33) | .03 |
| UD | 0.92 (0.66-1.28) | .62 | 1.19 (0.96-1.48) | .11 | 1.28 (1.01-1.61) | .04 | 1.18 (1.02-1.36) | .02 |
| Tumor size, cm | ||||||||
| ≤5.00 | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| 5.01-10.00 | 1.70 (1.30-2.22) | <.001 | 1.84 (1.56-2.18) | .001 | 1.47 (1.25-1.73) | .001 | 1.64 (1.48-1.83) | .001 |
| 10.01-15.00 | 1.92 (1.38-2.67) | <.001 | 1.77 (1.45-2.16) | .001 | 1.71 (1.40-2.09) | .001 | 1.78 (1.56-2.02) | .001 |
| >15.00 | 1.36 (0.93-1.99) | .11 | 1.53 (1.25-1.88) | .001 | 1.29 (1.04-1.59) | .02 | 1.43 (1.25-1.64) | .001 |
| Clinical tumor stage | ||||||||
| I | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| II | 1.63 (1.24-2.14) | <.001 | 1.99 (1.69-2.36) | .001 | 1.60 (1.35-1.89) | .001 | 1.76 (1.58-1.97) | .001 |
| Unknown | 1.27 (0.92-1.77) | .152 | 1.43 (1.17-1.74) | <.001 | 1.15 (0.95-1.40) | .16 | 1.29 (1.13-1.46) | <.001 |
| Depth of extension | ||||||||
| Superficial | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Deep | 1.85 (1.42-2.42) | .001 | 1.64 (1.40-1.91) | .001 | 1.30 (1.12-1.51) | <.001 | 1.51 (1.37-1.67) | .001 |
| Unknown | 1.20 (0.80-1.82) | .38 | 1.07 (0.83-1.39) | .59 | 0.97 (0.74-1.25) | .79 | 1.03 (0.87-1.22) | .72 |
| Surgical margin | ||||||||
| Negative | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA | 1 [Reference] | NA |
| Positive | 1.33 (0.89-2.01) | .17 | 1.33 (1.06-1.65) | .01 | 1.26 (1.05-1.50) | .01 | 1.27 (1.12-1.45) | <.001 |
| Unknown | 0.75 (0.43-1.29) | .30 | 1.39 (0.93-2.07) | .11 | 1.22 (0.86-1.73) | .26 | 1.15 (0.91-1.45) | .24 |
| Age, y | ||||||||
| 18-39 | NA | NA | NA | NA | NA | NA | 1 [Reference] | NA |
| 40-64 | NA | NA | NA | NA | NA | NA | 1.53 (1.35-1.75) | .001 |
| ≥65 | NA | NA | NA | NA | NA | NA | 1.19 (1.04-1.35) | .009 |
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.