Demographic characteristics of patients included in the DHNA-OC cohort
| Characteristic | n=2545 |
| Gender - female | 1171 (46%) |
| Age | 67 (59, 75) |
| Body mass index (kg/m2) | |
| <18.5 | 102 (4.0%) |
| ≥18.5 to <30 | 1953 (77%) |
| ≥30 | 419 (16%) |
| Unknown | 71 (2.8%) |
| Smoking history | |
| No history of smoking | 639 (25%) |
| Former smoker | 852 (33%) |
| Current smoker | 945 (37%) |
| Unknown | 109 (4.3%) |
| Alcohol history | |
| No history of drinking | 419 (16%) |
| Former drinker | 196 (7.7%) |
| Current drinker | 1712 (67%) |
| Unknown | 218 (8.6%) |
| ACE27 score | |
| Grade 0 - None | 720 (28%) |
| Grade 1—Mild | 375 (15%) |
| Grade 2—Moderate | 248 (9.7%) |
| Grade 3—Severe | 90 (3.5%) |
| Unknown | 1112 (44%) |
| WHO performance status | |
| Normal activity (0) | 1268 (50%) |
| Symptomatic, fully ambulatory: cares for self (1) | 501 (20%) |
| Ambulatory >50% of the time: occasional assistance (2) | 178 (7.0%) |
| Ambulatory <50% of the time: nursing care needed (3) | 41 (1.6%) |
| Bedridden (4) | 1 (<0.1%) |
| Unknown | 556 (22%) |
| Histology | |
| Squamous cell carcinoma | 2328 (91%) |
| Other | 216 (9.0%) |
| Unknown | 1 (<0.1%) |
| Oral cavity subsite (ICD-O-3) | |
| Lip | 54 (2.1%) |
| Tongue | 1105 (43%) |
| Gum | 449 (18%) |
| Floor of mouth | 426 (17%) |
| Palate | 86 (3.4%) |
| Other parts of oral cavity | 423 (17%) |
| Not otherwise specified | 2 (<0.1%) |
| cT-classification | |
| cTx | 25 (1.0%) |
| cT0 | 7 (0.3%) |
| cTis | 23 (0.9%) |
| cT1 | 825 (32%) |
| cT2 | 783 (31%) |
| cT3 | 343 (13%) |
| cT4 | 539 (21%) |
| cN-classification | |
| cNx | 14 (0.6%) |
| cN0 | 2001 (79%) |
| cN1 | 194 (7.6%) |
| cN2 | 292 (11%) |
| cN3 | 44 (1.7%) |
| cM-classification | |
| cMx | 2 (<0.1%) |
| cM0 | 2541 (100%) |
| cM1 | 2 (<0.1%) |
| cTNM stage | |
| Stage 0 | 53 (2.1%) |
| Stage I | 791 (31%) |
| Stage II | 643 (25%) |
| Stage III | 342 (13%) |
| Stage IV | 716 (28%) |
| Treatment | |
| Surgery | 1441 (57%) |
| Surgery and radiotherapy | 724 (28%) |
| Surgery and chemoradiation | 185 (7.3%) |
| Radiotherapy | 111 (4.4%) |
| Chemoradiation | 71 (2.8%) |
| Other* | 13 (0.5%) |
| Treating hospital | |
| HNOCs | 1926 (76%) |
| PPs | 619 (24%) |
| Year of diagnosis | |
| 2018 | 626 (25%) |
| 2019 | 626 (25%) |
| 2020 | 631 (25%) |
| 2021 | 662 (26%) |
| Follow-up survival status | |
| No evidence of disease | 1942 (76%) |
| Alive with disease | 63 (2.5%) |
| Dead of disease | 188 (7.4%) |
| Dead of other causes | 97 (3.9%) |
| Dead of treatment complications | 10 (0.4%) |
| Dead of unknown causes | 167 (6.6%) |
| Unknown | 78 (3.1%) |
*Histology types included in other are basaloid squamous cell, spindle cell, adenosquamous, verrucous, papillary squamous cell, and minor salivary gland carcinomas
DHNA-OC, Dutch Head and Neck Audit—Oral Cavity; HNOC, Head and Neck Oncolocy Center; PP, Preferred Partner .