Table 1.
Patient characteristics of the OUS and MAASTRO datasets.
| Characteristics | OUS (n = 139) | MAASTRO (n = 99) | p-valuec |
|---|---|---|---|
| Age (years) | |||
| Mean ± SD (median) | 60.2 ± 7.7 (60) | 61.6 ± 9.5 (61) | ns |
| Gender | |||
| Female | 32 (23.0%) | 26 (26.3%) | ns |
| Male | 107 (77.0%) | 73 (73.7%) | |
| Smoking (pack years) | |||
| Mean ± SD (median) | 25.0 ± 22.8 (22.5) | 46.1 ± 47.5 (40.0) | <0.0001 |
| Tumor site | |||
| Oral cavity | 11 (7.9%) | 3 (3.0%) | ns |
| Oropharynx | 91 (65.5%) | 44 (44.4%) | <0.01 |
| Hypopharynx | 16 (11.5%) | 15 (15.2%) | ns |
| Larynx | 21 (15.1%) | 37 (37.4%) | <0.001 |
| Overall stage (TNM8 a ) | |||
| I–II | 72 (51.8%) | 19 (19.2%) | <0.0001 |
| III–IV | 67 (48.2%) | 80 (80.8%) | |
| HPV-related b | |||
| Yes | 80 (57.6%) | 22 (22.2%) | <0.0001 |
| No | 59 (42.4%) | 77 (77.8%) | |
| Histologic grade | |||
| Low/moderate | 43 (30.9%) | 59 (59.6%) | <0.0001 |
| High | 96 (69.1%) | 40 (40.4%) | |
| Charlson comorbidity index | |||
| 0 | 86 (61.9%) | 25 (25.3%) | <0.0001 |
| 1–6 | 53 (38.1%) | 74 (74.7%) | |
| SUVpeak | |||
| Mean ± SD (median) | 11.0 ± 5.4 (10.0) | 11.2 ± 6.2 (10.6) | ns |
| MTV | |||
| Mean ± SD (median) | 11.9 ± 13.5 (7.1) | 15.1 ± 12.0 (10.9) | <0.001 |
| TLG | |||
| Mean ± SD (median) | 121.0 ± 194.7 (56.6) | 109.9 ± 105.6 (74.1) | 0.03 |
| DFS | |||
| Event (class 1) | 68 (48.9%) | 59 (59.6%) | ns |
| Non-event (class 0) | 71 (51.1%) | 40 (40.4%) | |
| OS | |||
| Event (class 1) | 57 (41.0%) | 53 (53.5%) | ns |
| Non-event (class 0) | 82 (59.0%) | 46 (46.5%) | |
OUS, Oslo University Hospital; MAASTRO, Maastro Clinic, Maastricht; HPV, human papillomavirus; MTV, metabolic tumor volume; TLG, total lesion glycolysis; DFS, disease-free survival; OS, overall survival; ns, not significant.
a
According to the 8th edition tumor—node—metastasis (TNM) system.
b
HPV-related defined as HPV positive oropharyngeal cancers.
c
p-values for unpaired Wilcoxon rank sum tests (continuous variables) and two-proportion z-tests (categorical variables) assessing the similarity in patient characteristics between the two cohorts (significance level: 0.05).