Statistical comparison of survival models for analysis of cancer data.
BACKGROUND
The Cox Proportional Hazard model is the most popular technique to analysis the effects of covariates on survival time but under certain circumstances parametric models may offer advantages over Cox's model. In this study we use Cox regression and alternative parametric models such as: Weibull, Exponential and Lognormal models to evaluate prognostic factors affecting survival of patients with stomach cancer. Comparisons were made to find the best model.


METHODS
To determine independent prognostic factors reducing survival time for stomach cancer, we compared parametric and semi-parametric methods applied to patients who registered in one cancer registry center located in southern Iran using the Akaike Information Criterion.


RESULTS
Of a total of 442 patients, 266 (60.2%) died. The results of data analysis using Cox and parametric models were approximately similar. Patients with ages 60-75 and >75 years at diagnosis had an increased risk for death followed by those with poor differentiated grade and presence of distant metastasis (P<0.05).


CONCLUSIONS
Although the Hazard Ratios in the Cox model and parametric ones are approximately similar, according to Akaike Information Criterion, the Weibull and Exponential models are the most favorable for survival analysis.
Moghimi-Dehkordi
Bijan
B
Research Center for Gastroenterology and Liver Diseases, Shaheed Beheshti University MC, Tehran, Iran. b_moghimi_de@ yahoo.com
Safaee
Azadeh
A
Pourhoseingholi
Mohamad Amin
MA
Fatemi
Reza
R
Tabeie
Ziaoddin
Z
Zali
Mohammad Reza
MR
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007492:Iran; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D016019:Survival Analysis