Table 3.
Results of GAM and proportional hazards tests for SEER data
| Overall mortality | Node-negative | Node-positive | ||||
| no transform | transform age+|age-50|1.5 | transform age+|age-50|1.8 | no transform | transform age+|age-50|1.5 | transform age+|age-50|1.8 | |
| GAM Chisq for Age (smaller value better) | 582.4 | 6.53 | 52.4 | 439.2 | 18.4 | 1.83 |
| GAM p-value for Age (larger better) | <.0001 | 0.089 | <.0001 | <.0001 | 0.0003 | 0.557 |
| Test PH for Age: rho (smaller absolute value better) | 0.069 | 0.071 | 0.075 | 0.048 | 0.044 | 0.045 |
| Test PH for Age: chisq (smaller value better) | 53.6 | 46.3 | 48.2 | 21.1 | 15.8 | 16.0 |
| Full PH model Rsquare (larger value better) | 0.088 | 0.094 | 0.093 | 0.126 | 0.135 | 0.135 |
| Full PH model Likelihood ratio test (larger value better) | 5364 | 5745 | 5656 | 3443 | 3713 | 3709 |
| Breast cancer specific mortality | Node-negative | Node-positive | ||||
| no transform | transform age+|age-50|1.5 | transform age+|age-50|1.8 | no transform | transform age+|age-50|1.5 | transform age+|age-50|1.8 | |
| GAM Chisq for Age (smaller value better) | 52.7 | 11.1 | 8.10 | 63.7 | 9.20 | 4.92 |
| GAM p-value for Age (larger better) | <.0001 | 0.010 | 0.040 | <.0001 | 0.027 | 0.179 |
| Test PH for Age: rho (smaller absolute value better) | -0.027 | -0.038 | -0.042 | -0.007 | -0.023 | -0.027 |
| Test PH for Age: chisq (smaller value better) | 2.5 | 4.5 | 5.5 | 0.3 | 2.8 | 3.6 |
| Full PH model Rsquare (larger value better) | 0.03 | 0.03 | 0.031 | 0.1 | 0.1 | 0.1 |
| Full PH model Likelihood ratio test (larger value better) | 1779 | 1799 | 1803 | 2698 | 2715 | 2716 |
Chisq = chi-square value, GAM = generalized additive model, PH = proportional hazards. The additional file 3 "output4rev.doc" lists the output of the full PH models.