Results of multivariate survival analysis.
| Characteristic | Observation | P value |
| Age (years) | 0.66 | |
| <65 | Reference | |
| ≥65 | 1.10 (0.72 to 1.68) | |
| Co-morbidities | 0.002 | |
| No | Reference | |
| Yes | 1.61 (1.20 to 2.18) | |
| History of another tumor | 0.003 | |
| No | Reference | |
| Yes | 1.58 (1.17 to 2.14) | |
| Insurance | 0.001 | |
| Private | Reference | |
| Government | 2.01 (1.31 to 3.07) | |
| Reporting facility | 0.009 | |
| Non-academic | Reference | |
| Academic | 0.69 (0.52 to 0.91) | |
| Tumor size (cm) | <0.001 | |
| <2 | Reference | |
| ≥2 | 2.20 (1.53 to 3.17) | |
| Unknown | 1.41 (0.97 to 2.05) | |
| Adjuvant treatment | 0.023 | |
| Observation | Reference | |
| Chemotherapy | 0.64 (0.42 to 0.96) | |
| Radiotherapy | 0.85 (0.53 to 1.37) | |
| Chemoradiation | 0.55 (0.35 to 0.88) |