Table 3.
The univariate analysis.
| Variable | N | OS | DFS | LC | ||||
|---|---|---|---|---|---|---|---|---|
| Censored | p | Censored | p | Censored | p | |||
| Gender | male | 5 | 3 | 0.136 | 3 | 0.830 | 0 | 0.217 |
| female | 6 | 0 | 2 | 2 | ||||
| Age (years) | >60 | 7 | 1 | 0.546 | 3 | 0.663 | 1 | 0.763 |
| ≤60 | 4 | 2 | 2 | 1 | ||||
|
Anatomical
Site |
Oropharynx SCC p16 negative |
4 | 1 | 0.013 | 2 | 0.142 | 1 | 0.627 |
| Oropharynx SCC p16 positive |
1 | 0 | 0 | 0 | ||||
| Oral cavity | 2 | 2 | 2 | 0 | ||||
| Salivary gland | 1 | 0 | 0 | 0 | ||||
| Lymph node | 3 | 0 | 1 | 1 | ||||
| Margin status | Free | 6 | 2 | 0.529 | 2 | 0.459 | 0 | 0.186 |
| Microscopic positive | 3 | 0 | 1 | 1 | ||||
| Gross residual disease | 2 | 1 | 2 | 1 | ||||
| Perineural Invasion | 2 | 0.829 | 2 | 0.123 | ||||
| No | 3 | 1 | 2 | 0 | ||||
| Previous EBRT total dose | >60 Gy | 7 | 2 | 0.658 | 3 | 0.666 | 2 | 0.251 |
| ≤60 Gy | 4 | 1 | 2 | 0 | ||||
| Interval between salvage surgery to the start of PO-SABR (days) | ≤30 | 7 | 2 | 0.248 | 3 | 0.722 | 1 | 0.117 |
| >30 | 4 | 1 | 2 | 1 | ||||
| PO-SABR total dose | >40 Gy | 9 | 1 | 0.078 | 3 | 0.222 | 1 | 0.102 |
| ≤40 Gy | 2 | 2 | 2 | 1 | ||||
| PO-SABR–number of fractions | >3 | 8 | 1 | 0.051 | 3 | 0.341 | 0 | 0.465 |
| ≤3 | 3 | 2 | 2 | 2 | ||||
|
Interval first EBRT and salvage PO-SABR
(months) |
>24 | 9 | 1 | 0.033 | 3 | 0.225 | 2 | 0.540 |
| ≤24 | 2 | 2 | 2 | 0 | ||||
| Total | 11 | 3 | 5 | 2 | ||||
Legend: N—number of patients, OS—overall survival, DFS—disease free survival, LC—local control, SCC—squamous cell carcinoma, EBRT—external beam radiotherapy, PO-SABR—post-operative stereotactic ablative radiation therapy.