Table 1. Demographic and exposure characteristics of cases and controls.
| Characteristic | Controls (N=782) | Non-OPC (N=153) | Pa | p16+ OPC (N=348) | Pa | P16+/HPV ISH+ OPC (N=271)b | Pa |
|---|---|---|---|---|---|---|---|
| Age, mean (SD), years | 55.6 (11.8) | 54.1 (15.2) | 0.253c | 56.7 (8.8) | 0.088c | 56.6 (9.1) | 0.143c |
| Age, median (IQR), years | 55 (49-63) | 54 (44-64) | 0.219 | 56 (51-62) | 0.853 | 56 (50-63) | 0.814 |
| Sex, no. (%) | 0.014 | 0.011 | 0.006 | ||||
| Male | 622 (79.5) | 108 (70.6) | 299 (85.9) | 236 (87.1) | |||
| Female | 160 (20.5) | 45 (29.4) | 49 (14.1) | 35 (12.9) | |||
| Race, no. (%) | 0.118 | 0.202 | 0.252 | ||||
| White | 690 (88.2) | 128 (83.7) | 316 (90.8) | 246 (90.8) | |||
| Other | 92 (11.8) | 25 (16.3) | 32 (9.2) | 25 (9.2) | |||
| Smoking, no. (%) | <0.001 | 0.021 | 0.045 | ||||
| Never | 303 (51.4) | 59 (42.5) | 128 (43.7) | 100 (44.1) | |||
| Former | 217 (36.8) | 36 (25.9) | 113 (38.6) | 87 (38.3) | |||
| Current | 69 (11.7) | 44 (31.7) | 52 (17.8) | 40 (17.6) | |||
| Missing | 193 | 14 | 55 | 44 | |||
| Pack-years of smoking, no. (%) | 0.004 | 0.053 | 0.157 | ||||
| ≤10 | 410 (69.6) | 79 (56.8) | 183 (63.1) | 145 (64.4) | |||
| >10 | 179 (30.4) | 60 (43.2) | 107 (36.9) | 80 (35.6) | |||
| Missing | 193 | 14 | 58 | 46 | |||
| Alcohol use, no. (%) | 0.229 | <0.001 | <0.001 | ||||
| Never | 267 (45.3) | 52 (37.4) | 78 (26.6) | 62 (27.3) | |||
| Former | 105 (17.8) | 27 (19.4) | 79 (27.0) | 57 (25.1) | |||
| Current | 217 (36.8) | 60 (43.2) | 136 (46.4) | 108 (47.6) | |||
| Missing | 193 | 14 | 55 | 44 | |||
| p16/HPV ISH status, no. (%) | |||||||
| p16+/ISH+ | -- | 11 (8.9) | 271 (80.4) | 271 (100.0) | |||
| p16+/ISH- | -- | 22 (17.9) | 66 (19.6) | -- | |||
| p16-/ISH+ | -- | 0 | -- | -- | |||
| p16-/ISH- | -- | 90 (73.2) | -- | -- | |||
| Missing ISH | -- | 30 | 11 | -- | |||
| HPV antibody status, no. (%) | |||||||
| E1+ | 52 (6.7) | 12 (7.8) | 0.593 | 256 (73.6) | <0.001 | 204 (75.3) | <0.001 |
| NE2+ | 14 (1.8) | 5 (3.3) | 0.236 | 128 (36.8) | <0.001 | 106 (39.1) | <0.001 |
| CE2+ | 7 (0.9) | 5 (3.3) | 0.017 | 235 (67.5) | <0.001 | 193 (71.2) | <0.001 |
| E4+ | 14 (1.8) | 8 (5.2) | 0.010 | 110 (31.6) | <0.001 | 95 (35.1) | <0.001 |
| E5+ | 48 (6.1) | 11 (7.2) | 0.625 | 37 (10.6) | 0.008 | 29 (10.7) | 0.013 |
| E6+ | 9 (1.2) | 4 (2.6) | 0.157 | 146 (42.0) | <0.001 | 114 (42.1) | <0.001 |
| E7+ | 11 (1.4) | 5 (3.3) | 0.104 | 224 (64.4) | <0.001 | 177 (65.3) | <0.001 |
| E6+ and/or E7+ | 18 (2.3) | 7 (4.6) | 0.111 | 259 (74.4) | <0.001 | 205 (75.7) | <0.001 |
| L1+ | 11 (1.4) | 4 (2.6) | 0.287d | 27 (7.8) | <0.001 | 24 (8.9) | <0.001 |
| L2+ | 57 (7.3) | 10 (6.5) | 0.741 | 39 (11.2) | 0.029 | 36 (13.3) | <0.001 |
| Binary classifier positivee | 8 (1.0) | 4 (2.6) | 0.110 | 288 (82.8) | <0.001 | 231 (85.2) | <0.001 |
a
p values are for comparison to controls
b
A subset of p16+ OPC cases that are also HPV ISH+; note that HPV ISH was unavailable for 11 p16+ OPC
c
Adjusted for unequal variances
d
Fisher's exact test
e
Binary classifier is based on a combination of antibodies based on receiver operating characteristics analysis; ≥0.5 is considered positive
E: early protein; HPV: human papillomavirus; IQR: interquartile range; ISH: in situ hybridization; L: late protein; OPC: oropharyngeal cancer; SD: standard deviation