Table 8.
Multivariable Cox Regression Modeling Analysis on Survival Disparities of Race/Ethnicity for All Histologies of SGCA 1
| Model 1 3
|
Model 2 3
|
Model 3 3
|
Model 4 3
|
|
|---|---|---|---|---|
| HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | |
| Race/Ethnicity 4 | ||||
| White | Ref. | Ref. | Ref. | Ref. |
| Hispanic | 0.70 (0.58 to 0.86) | 0.97 (0.79 to 1.19) | 0.94 (0.77 to 1.15) | 0.97 (0.79 to 1.19) |
| Black | 0.97 (0.82 to 1.15) | 1.34 (1.13 to 1.60) | 1.29 (1.08 to 1.54) | 1.22 (1.03 to 1.46) |
| Gender | ||||
| Male | Ref. | Ref. | Ref. | |
| Female | 0.73 (0.65 to 0.81) | 1.00 (0.90 to 1.12) | 1.00 (0.89 to 1.11) | |
| Age at Diagnosis | ||||
| ≤ 49 | Ref. | Ref. | Ref. | |
| 49 to 65 | 2.19 (1.84 to 2.61) | 1.46 (1.22 to 1.74) | 1.40 (1.17 to 1.67) | |
| 65 to 75 | 3.43 (2.87 to 4.10) | 2.11 (1.76 to 2.53) | 2.03 (1.69 to 2.44) | |
| > 75 | 4.92 (4.13 to 5.85) | 2.76 (2.31 to 3.31) | 2.58 (2.15 to 3.09) | |
| Histology | ||||
| Mucoepidermoid Carcinoma | Ref. | Ref. | ||
| Adenocarcinoma | 1.52 (1.28 to 1.80) | 1.47 (1.24 to 1.74) | ||
| Adenoid Cystic Carcinoma | 1.16 (0.93 to 1.44) | 1.11 (0.89 to 1.34) | ||
| Squamous Cell Carcinoma | 0.95 (0.80 to 1.14) | 0.85 (0.71 to 1.01) | ||
| Acinar Cell Carcinoma | 0.69 (0.52 to 0.92) | 0.75 (0.56 to 0.99) | ||
| Other Malignant Histologies | 1.32 (1.11 to 1.56) | 1.21 (1.02 to 1.44) | ||
| Tumor Grade 2 | ||||
| Low | Ref. | Ref. | ||
| High | 2.45 (2.07 to 2.90) | 2.22 (1.87 to 2.63) | ||
| Tumor Size (mm) 2 | ||||
| ≤ 17 | Ref. | Ref. | ||
| 17 to 25 | 1.78 (1.41 to 2.24) | 1.75 (1.39 to 2.21) | ||
| 25 to 37 | 2.14 (1.70 to 2.70) | 2.07 (1.65 to 2.61) | ||
| > 37 | 3.03 (2.43 to 3.78) | 2.74 (2.19 to 3.41) | ||
| Extension 2 | ||||
| Intraglandular | Ref. | Ref. | ||
| Extraglandular | 2.55 (2.24 to 2.91) | 2.40 (2.11 to 2.74) | ||
| Metastatic | 6.29 (5.09 to 7.77) | 4.29 (3.43 to 5.36) | ||
| Lymph Nodes 2 | ||||
| No Involvement | Ref. | Ref. | ||
| Positive | 2.34 (2.06 to 2.66) | 2.27 (2.00 to 2.57) | ||
| Surgery | ||||
| Yes | Ref. | |||
| No | 2.66 (2.32 to 3.06) | |||
In Cox regression analysis, only patients with complete treatment characteristics were considered (N=10,745). Age at diagnosis and tumor size were divided into quartiles. For age at diagnosis, the second quartile, 62, was replace by 65. Except for model 1 (crude model), diagnosis year was included into the models (not shown).
For carrying out the analyses for all models with the same number of patients, the patients with unknown tumor grade, tumor size, extension, or lymph nodes were included.
When fitting the Cox regression models, the assumption of proportionality was assessed by the significance of a term of the predictor associated with the logarithm of survival time, and an appropriate stratified analysis was adopted if needed. In model 2 (patient characteristics) and model 3 (patient and tumor characteristics), there were no violations of this assumption. In model 4 (patient, tumor and treatment characteristics), a severe violation appeared on radiation (yes/no) and a stratified Cox model on radiation was built; therefore, while not shown, radiation is included in model 4.
The corresponding p values of hazard ratios (HR) on the disparity of Hispanic versus White (H/W) and Black versus White (B/W) were shown as follows. In model 1, H/W and B/W were 0.001 and 0.74, respectively; in model 2, H/W and B/W were 0.76 and 0.001, respectively; in model 3, H/W and B/W were 0.55 and 0.005, respectively and in model 4, H/W and B/W were 0.77 and 0.03, respectively. Bold values highlight statistically significant results (p < 0.05).