Table 2.
Univariate analysis of overall and disease‐free survival rates
| Prognostic indicator | Overall survival (n = 170) | Disease‐free survival (n = 170) | ||||
|---|---|---|---|---|---|---|
| Risk ratio | 95% Confidence interval | P‐value | Risk ratio | 95% Confidence interval | P‐value | |
| Depth of invasion | ||||||
| T1–2/3–4 | 2.475 | 1.255–4.878 | 0.009 | 2.294 | 1.179–4.464 | 0.015 |
| Lymph node involvement | ||||||
| Present/absent | 3.293 | 1.621–6.691 | 0.001 | 4.003 | 1.804–8.884 | 0.001 |
| Blood vessel invasion | ||||||
| v +/– | 2.031 | 1.071–3.849 | 0.030 | 2.570 | 1.205–5.479 | 0.015 |
| Lymphatic vessel invasion | ||||||
| Ly +/– | 2.679 | 4.966–7.432 | 0.058 | 4.200 | 1.019–17.323 | 0.047 |
| HIF‐1α expression | ||||||
| High score/low score † | 1.554 | 0.903–2.624 | 0.112 | 1.963 | 1.078–3.573 | 0.027 |
Hypoxia‐inducible factor (HIF)‐1α protein scores were classified as follows: The intensity of cytoplasmic staining was scored as absent, weak, moderate, and strong. The extent of cytoplasmic staining was expressed as the percentage of positive cancer cells, from 0 to 100%. Tumors were scored using a four‐scale system according to the intensity and extent of staining. Score 1: tumors with absent or weak cytoplasmic reactivity and no nuclear staining; score 2: tumors with moderate or strong cytoplasmic reactivity in a percentage of positive cancer cells lower than the mean value, and with no nuclear staining; score 3: tumors with moderate or strong cytoplasmic reactivity in a percentage of positive cancer cells higher than the mean value; score 4: tumors with a clear nuclear reactivity (with or without cytoplasmic reactivity and regardless of the intensity). Tumors with scores 1 and 2 for HIF‐1α immunostaining were classified as the low‐score group, while tumors with scores 3 and 4 were classified as the high‐score group.