Table 1. Clinical Characteristics and Relation to Positive Surgical Margins.
| Characteristic | Total Sample (n= 16,326) | Negative Margins (n = 13,394) | Positive Margins (n = 2,932) | Effect Index (95% CI) | p-value |
|---|---|---|---|---|---|
| Age, yr, mean (SD) | 62.3 (12.7) | 62.6 (12.7) | 63.1 (12.5) | 1.00 (1.00–1.01) | 0.039 |
| Male | 64.6 | 64.4 | 65.7 | 1.06 (0.97–1.15) | 0.189 |
| Race | |||||
| Non-Hispanic White | 77.4 | 77.8 | 75.8 | [Reference] | NA |
| Black | 9.1 | 8.7 | 10.5 | 1.24 (1.08–1.41) | 0.002 |
| Hispanic | 7.1 | 6.9 | 7.9 | 1.17 (1.01–1.36) | 0.038 |
| Asian-Pacific Islander | 4.3 | 4.4 | 3.7 | 0.86 (0.69–1.05) | 0.149 |
| Other-unknown | 2.1 | 2.1 | 2.0 | 0.99 (0.74–1.30) | 0.927 |
| Insurance | |||||
| Private | 33.8 | 34.6 | 30.1 | [Reference] | NA |
| Uninsured | 5.6 | 5.5 | 6.1 | 1.29 (1.07–1.54) | 0.005 |
| Medicare-Medicaid or other government | 59.2 | 58.5 | 62.4 | 1.23 (1.12–1.34) | <0.001 |
| Unknown | 1.4 | 1.4 | 1.3 | 1.10 (0.76–1.55) | 0.591 |
| Median income quartiles | |||||
| <$30,000 | 16.2 | 16.1 | 16.6 | [Reference] | NA |
| $30,000-$34,999 | 20.5 | 20.7 | 19.7 | 0.92 (0.80–1.06) | 0.255 |
| $35,000-$45,999 | 28.8 | 28.6 | 30.0 | 1.01 (0.89–1.16) | 0.839 |
| $46,000 | 34.5 | 34.7 | 33.7 | 0.94 (0.83–1.07) | 0.321 |
| Education level of zip code | |||||
| 29% no HSD | 19.8 | 19.8 | 19.8 | [Reference] | NA |
| 20%−28.9% no HSD | 26.0 | 26.0 | 25.7 | 0.99 (0.87–1.12) | 0.873 |
| 14%−19.9% no HSD | 24.8 | 24.8 | 24.8 | 1.00 (0.88–1.14) | 0.982 |
| <14% no HSD | 29.4 | 29.3 | 29.7 | 1.01 (0.90–1.15) | 0.833 |
| Charlson Comorbidity Index | |||||
| 0 | 72.1 | 72.3 | 71.1 | [Reference] | NA |
| 1 | 19.8 | 19.7 | 20.3 | 1.05 (0.95–1.16) | 0.366 |
| 2 | 5.1 | 5.0 | 5.4 | 1.09 (0.91–1.30) | 0.36 |
| 3+ | 3.0 | 3.0 | 3.3 | 1.13 (0.90–1.41) | 0.291 |
| Setting | |||||
| Metropolitan | 77.8 | 77.7 | 78.4 | [Reference] | NA |
| Urban | 19.7 | 19.8 | 18.9 | 0.94 (0.85–1.05) | 0.282 |
| Rural | 2.5 | 2.4 | 2.7 | 1.11 (0.86–1.42) | 0.42 |
| Year of diagnosis | 0.99 (0.98–1.00) | 0.113 | |||
| 2004 | 3.0 | 3.1 | 2.8 | ||
| 2005 | 3.0 | 2.9 | 3.1 | ||
| 2006 | 3.5 | 3.4 | 4.1 | ||
| 2007 | 4.1 | 4.1 | 4.3 | ||
| 2008 | 5.3 | 5.3 | 5.4 | ||
| 2009 | 6.0 | 6.0 | 6.1 | ||
| 2010 | 6.4 | 6.4 | 6.3 | ||
| 2011 | 6.6 | 6.7 | 6.3 | ||
| 2012 | 7.1 | 7.0 | 7.8 | ||
| 2013 | 7.8 | 7.5 | 8.8 | ||
| 2014 | 8.2 | 8.3 | 8.2 | ||
| 2015 | 8.9 | 9.0 | 8.1 | ||
| 2016 | 9.2 | 9.3 | 8.7 | ||
| 2017 | 9.5 | 9.5 | 9.2 | ||
| 2018 | 11.4 | 11.5 | 11.0 | ||
| Subsite | |||||
| Oral tongue | 27.5 | 28.4 | 23.5 | [Reference] | NA |
| Lip | 2.1 | 2.3 | 1.4 | 0.75 (0.53–1.03) | 0.091 |
| Gum-alveolar ridge | 23.6 | 23.9 | 22.4 | 1.13 (1.01–1.27) | 0.038 |
| Floor of mouth | 20.2 | 19.8 | 22.1 | 1.34 (1.19–1.51) | <0.001 |
| Hard palate | 4.3 | 3.8 | 6.2 | 1.96 (1.62–2.36) | <0.001 |
| Other * | 22.3 | 21.8 | 24.3 | 1.34 (1.20–1.51) | <0.001 |
| Clinical T category | |||||
| cT3 | 29.5 | 30.8 | 23.5 | [Reference] | NA |
| cT4 | 70.5 | 69.2 | 76.5 | 1.46 (1.33–1.60) | <0.001 |
| Clinical N category | |||||
| cN0 | 47.2 | 48.5 | 41.2 | [Reference] | NA |
| cN1 | 16.6 | 16.5 | 17.2 | 1.23 (1.09–1.37) | <0.001 |
| cN2 | 35.0 | 33.9 | 39.9 | 1.39 (1.27–1.52) | <0.001 |
| cN3 | 1.2 | 1.1 | 1.7 | 1.80 (1.29–2.48) | <0.001 |
| Lymphovascular invasion | |||||
| Negative | 71.4 | 73.7 | 60.8 | [Reference] | NA |
| Positive | 28.6 | 26.3 | 39.2 | 1.81 (1.63–1.99) | <0.001 |
| Histologic grade | |||||
| Well differentiated | 18.2 | 19.4 | 13.0 | [Reference] | NA |
| Moderately differentiated | 61.4 | 61.3 | 61.8 | 1.50 (1.32–1.71) | <0.001 |
| Poorly differentiated-Undifferentiated | 20.4 | 19.3 | 25.2 | 1.94 (1.68–2.25) | <0.001 |
| Distance to treatment center | |||||
| <=50 miles | 71.6 | 71.0 | 74.4 | [Reference] | NA |
| >50 miles | 28.4 | 29.0 | 25.6 | 0.84 (0.77–0.93) | <0.001 |
| Region | |||||
| South Atlantic | 22.5 | 22.7 | 21.5 | [Reference] | NA |
| New England | 4.3 | 4.2 | 5.0 | 1.27 (1.04–1.56) | 0.02 |
| Middle Atlantic | 14.0 | 14.3 | 13.0 | 0.96 (0.84–1.11) | 0.604 |
| East North Central | 19.0 | 19.3 | 17.9 | 0.98 (0.86–1.11) | 0.755 |
| East South Central | 8.4 | 8.3 | 8.5 | 1.08 (0.91–1.27) | 0.363 |
| West North Central | 9.2 | 9.2 | 9.1 | 1.06 (0.89–1.23) | 0.543 |
| West South Central | 8.0 | 7.9 | 8.5 | 1.14 (0.97–1.34) | 0.117 |
| Mountain | 3.8 | 3.7 | 4.2 | 1.21 (0.97–1.50) | 0.084 |
| Pacific | 10.9 | 10.5 | 12.3 | 1.23 (1.07–1.43) | 0.005 |
| Academic center | |||||
| No | 31.2 | 30.2 | 35.6 | [Reference] | NA |
| Yes | 68.8 | 69.8 | 64.4 | 0.78 (0.72–0.85) | <0.001 |
| Treatment center volume | |||||
| Low (<=20 cases/yr) | 59.3 | 58.0 | 65.3 | [Reference] | NA |
| High (>20 cases/yr) | 40.7 | 42.0 | 34.7 | 0.73 (0.67–0.79) | <0.001 |
*
The “other” category for “subsite” includes hard palate, retromolar trigone, and mouth (overlapping or no otherwise specified)