Table 1.
Comparison of the patient and tumour characteristics of the training and validation cohort.
| Characteristics | Training cohort (2004–2012) |
Validation cohort (1999–2006) |
p-Value | ||
|---|---|---|---|---|---|
| Median (range) | Median (range) | ||||
| Follow-up (months) | 46.2 (2.5–100.1) | 43.1 (1.8–153) | 0.29 | ||
| Age (years) | 57.0 (24.0–75.2) | 52.7 (36.3–71.0) | 0.016 | ||
| Dose (Gy) | 64 (56–68) | 64 (60–66) | 0.001 | ||
| Number of pts | (%) | Number of pts | (%) | ||
| Gender | |||||
| Male/Female | 180/41 | (81/19) | 127/25 | (84/16) | 0.60 |
| Clinical tumour (T) stage | |||||
| cT1/cT2/cT3/cT4 | 41/98/47/35 | (19/44/21/16) | 40/69/24/19 | (26/45/16/13) | 0.20 |
| Clinical nodal (N) stage | |||||
| cN0/cN1/cN2/cN3 | 22/31/138/30 | (10/14/62/14) | 15/31/104/2 | (10/20/68/1) | <0.001 |
| Stage (UICC 7th edition) | |||||
| I/II/III/IV | 0/8/33/180 | (0/4/15/81) | 2/3/34/113 | (1/2/23/74) | 0.069 |
| R status | |||||
| 0/1/unknown | 125/94/2 | (57/42/1) | 109/30/13 | (72/20/8) | <0.001 |
| ECE status | |||||
| 0/1/unknown | 103/118/0 | (47/53/0) | 104/47/1 | (68/31/1) | <0.001 |
| Localisation | |||||
| Oropharynx/oral cavity/hypopharynx/larynx | 126/60/35/0 | (57/27/16/0) | 46/83/15/8 | (30/55/10/5) | <0.001 |
| Grading | |||||
| 1/2/3/unknown | 5/123/89/4 | (2/56/40/2) | 3/78/71/0 | (2/51/47/0) | 0.55 |
| Chemotherapy | |||||
| yes/no | 221/0 | (100/0) | 40/112 | (26/74) | <0.001 |
| Smoking during therapy | |||||
| yes/no/unknown | 186/20/15 | (84/9/7) | 103/16/33 | (68/11/22) | 0.30 |
| Alcohol during therapy | |||||
| yes/no/unknown | 100/30/91 | (45/14/41) | 99/19/34 | (65/13/22) | 0.17 |
| p16 status | |||||
| negative/positive/unknown | 135/79/7 | (61/36/3) | 128/20/4 | (84/13/3) | <0.001 |
| HPV16 DNA status | |||||
| negative/positive/unknown | 143/72/6 | (65/33/2) | 126/22/4 | (83/14/3) | <0.001 |
| CD44 protein | |||||
| negative/positive/unknown | 44/151/26 | (20/68/12) | 15/130/7 | (10/85/5) | 0.003 |
| CD44 (log2-normalised expression) | |||||
| ⩽0.2 / > 0.2 / unknown | 78/118/25 | (35/54/11) | 55/90/7 | (36/59/5) | 0.73 |
| SLC3A2 (log2-normalised expression) | |||||
| ⩽−3.135 />−3.135 / unknown | 77/119/25 | (35/54/11) | 43/102/7 | (28/67/5) | 0.066 |
| MET (log2-normalised expression) | |||||
| ⩽−4.135 />−4.135 / unknown | 94/102/25 | (43/46/11) | 47/98/7 | (31/64/5) | <0.001 |
| 15-gene hypoxia signature | |||||
| low hypoxic/highly hypoxic/unknown | 79/117/25 | (36/53/11) | 41/104/7 | (27/68/5) | 0.021 |
| 26-gene hypoxia signature | |||||
| low hypoxic/highly hypoxic/unknown | 72/124/25 | (33/56/11) | 22/123/7 | (14/81/5) | <0.001 |
| Loco-regional recurrences | 29 | (13) | 38 | (25) | 0.003 |
| Distant metastases | 42 | (19) | 24 | (22) | 0.43 |
| Deaths | 70 | (32) | 86 | (57) | <0.001 |
Bold numbers indicate significant p-Values with p < 0.05.