Table 5.
Evaluation of risk factors via Chi squared test (Fisher’s exact test when applicable) and calculation of relative risks
| Risk factors | n‡ total risk factor (PCF and No-PCF) | n‡ risk factor PCF† | Significance | Relative risk for PCF |
|---|---|---|---|---|
| Overview patient collecitve | 182 (100%) | 45 (25%) | ||
| Toxicants |
alcohol and nicotine = 166 diabetes = 167 |
nicotine and diabetes = 44 alcohol = 43 |
||
| Alcohol | 119 (72%) | 31 (72%) | p = 0.945 | 1.020 |
| Nicotine | 119 (72%) | 33 (75%) | p = 0.569 | 1.185 |
| Diabetes | 31 (19%) | 8 (20%) | p = 0.857 | 1.064 |
| Main tumor | n‡ = 174 | n‡ = 44 | p = 1.12 | |
| Hypopharynx | 55 (33%) | 19 (46%) | p = 0.054 | 1.667 |
| Larynx (reference) | 111 (67%) | 22 (54%) | ||
| Hypopharynx & larynx | 4 (3.5%) | 1 (4.2%) | p = 1,00eF | 1.207 |
| Thyroid gland | 4 (3.5%) | 1 (4.2%) | p = 1.00eF | 1.207 |
| Further entities | 8 (6.7%) | 1 (4.2%) | p = 1.00eF | 0.603 |
| TNM | n‡ = 174 | n‡ = 44 | ||
| T-status | ||||
| T1 | 9 (5%) | 1 (2%) | p = 0.244eF | 0.294 |
| T2 (reference) | 45 (26%) | 17 (39%) | ||
| T3 | 51 (29%) | 11 (25%) | p = 0.072 | 0.560 |
| T4 | 69 (39%) | 15 (34%) | p = 0.062 | 0.575 |
| N-status | ||||
| N0 (reference) | 85(49%) | 26 (59%) | ||
| N1 | 25 (14%) | 5 (11%) | p = 0.301 | 0.654 |
| N2 | 63 (36%) | 13 (29%) | p = 0.174 | 0.675 |
| N3 | 2 (1%) | 0 (0%) | p = 1.000eF | |
| M-status | ||||
| M0 (reference) | 170 (97%) | 43 (98%) | ||
| M1 | 5 (3%) | 1 (2%) | p = 1.000eF | 0.791 |
| RT & RCT§ | n‡ = 182 | n‡ = 45 | ||
| Previous RT§ | 20 (11%) | 4 (9%) | p = 0.786 | 0.790 |
| Previous RCT§ | 16 (9%) | 10 (22%) | p = 0.001* | 2.964* |
| Surgery related risk factors | ||||
| Voice prosthesis | 150 (86%) | 34 (77%) | p = 0.064 | 0.567 |
| Surgeon | p = 0.031* | 3.250* | ||
| Flap transplant | 21 (12%) | 6 (13%) | p = 0.664 | 1.179 |
| Radialis-flap | 18 (10%) | 5 (11%) | p = 0.775eF | 1.147 |
| Pectoralis-flap | 3 (2%) | 1 (2,5%) | p = 0.570eF | 1.376 |
| No transplant | 161(88%) | 39 (87%) | ||
| Preoperative parameters | ||||
| Anaemia | 54 (43%) | 15 (44%) | p = 0.862 | 1.053 |
| Hypothyroidism | 5 (7%) | 2 (12%) | p = 0.330 | 1.813 |
| AST/ALT > 1 | 56 (64%) | 18 (75%) | p = 0.201 | 1.661 |
Anaemia♂defined as haemoglobin < 13 g/dl for men and < 12 g/dl for women
Hypothyroidism defined as thyreoglobine stimulating hormone > 4.00 µU/ml
*Statistically significant
†PCF Pharyngocutaneous fistula
§RT radiotherapy; RCT radiochemotherapy
‡Number of valid cases; Percentage indication refers to number of valid cases
eF Fisher’s exact test