Table 1.
Baseline characteristics of the study population.
| Variable | p16 (−), n = 99 | p16 (+), n = 51 | p-Value | ||
|---|---|---|---|---|---|
| n | % | n | % | ||
| Male, n, % | 93 | 93.94 | 37 | 72.55 | <0.001 |
| Female, n, % | 6 | 6.06 | 14 | 27.45 | <0.001 |
| Age, mean, SD | 53.3 | 9.22 | 56.7 | 9.71 | 0.036 |
| Age, n, % | 0.085 | ||||
| <50 | 36 | 36.36 | 10 | 19.61 | |
| 50–59 | 35 | 35.35 | 20 | 39.22 | |
| ≥60 | 28 | 28.28 | 21 | 41.18 | |
| Cigarette smoking, n, % | 91 | 91.92 | 26 | 50.98 | <0.001 |
| Smoking age (pack-years), mean, SD | 31.8 | 26.8 | 14.4 | 17.9 | <0.001 |
| Smoking age (pack-years), n, % | <0.001 | ||||
| 0 | 8 | 8.08 | 25 | 49.02 | |
| 1–9 | 7 | 7.07 | 3 | 5.88 | |
| 10–19 | 14 | 14.14 | 0 | 0.00 | |
| 20–29 | 18 | 18.18 | 10 | 19.61 | |
| ≥30 | 52 | 52.53 | 13 | 25.49 | |
| Alcohol use, n, % | 86 | 86.87 | 26 | 50.98 | <0.001 |
| Betel quid chewing, n, % | 76 | 76.77 | 10 | 19.61 | <0.001 |
| ABC concomitant use, n, % | <0.001 | ||||
| 3 | 70 | 70.7 | 9 | 17.65 | |
| 2 of 3 | 20 | 20.2 | 12 | 23.53 | |
| Tumor subsite, n, % | 0.002 | ||||
| Tonsil | 47 | 47.47 | 40 | 78.43 | |
| Soft palate | 22 | 22.22 | 6 | 11.76 | |
| Tongue base | 23 | 23.23 | 5 | 9.80 | |
| Posterior pharyngeal wall | 7 | 7.07 | 0 | 0.00 | |
| Clinical stage (AJCC 7th ed.), n, % | 0.041 | ||||
| Stage I | 2 | 2.02 | 1 | 1.96 | |
| Stage II | 7 | 7.07 | 0 | 0.00 | |
| Stage III | 6 | 6.06 | 9 | 17.65 | |
| Stage IVA | 68 | 68.69 | 37 | 72.55 | |
| Stage IVB | 16 | 16.16 | 4 | 7.84 | |
| Clinical stage (AJCC 8th ed.), n, % | <0.001 | ||||
| Stage I | 2 | 2.02 | 26 | 50.98 | |
| Stage II | 7 | 7.07 | 15 | 29.41 | |
| Stage III | 5 | 5.05 | 10 | 19.61 | |
| Stage IVA | 55 | 55.56 | 0 * | 0.00 * | |
| Stage IVB | 30 | 30.3 | 0 * | 0.00 * | |
| Initial treatment, n, % | 0.024 | ||||
| Surgery | 32 | 32.32 | 7 | 13.73 | |
| RT-based therapy | 67 | 67.68 | 44 | 86.27 | |
| CCRT | 66 | 66.67 | 40 | 78.43 | |
| RT only | 1 | 1.01 | 4 | 7.84 | |
| Disease relapse, n, % | 58 | 58.59 | 13 | 25.49 | <0.001 |
| LRR | 25 | 25.25 | 6 | 11.76 | |
| DM | 18 | 18.18 | 5 | 9.80 | |
| LRR + DM | 15 | 15.15 | 2 | 3.92 | |
| Mortality, n, % | 61 | 61.62 | 9 | 17.65 | <0.001 |
| DOD | 47 | 47.47 | 5 | 9.80 | |
| Dead, other reason | 14 | 14.14 | 4 | 7.84 | |
* The clinical stage of nonmetastatic HPV-positive OPSCC was downstaged to stage III or less in the eighth edition of the American Joint Committee on Cancer (AJCC) staging system. Abbreviations: n, number of patients; SD, standard deviation; ABC, alcohol/betel nut/cigarette; AJCC, American Joint Committee on Cancer; ed., edition; RT, radiotherapy; CCRT, concurrent chemoradiotherapy; LRR, locoregional recurrence; DM, distant metastasis; DOD, died of disease.