Estimation of hazard function and its associated factors in gastric cancer patients using wavelet and kernel smoothing methods

The increase of mortality rate of gastric cancer in Iran and World in recent years, reveal necessity of studies on this disease. In this study, Hazard Function for gastric cancer patients was estimated using Wavelet and Kernel methods to compare, and some related factors with the Hazard Function were assessed.
Material & Ninety-five gastric cancer patients in Fayazbakhsh Hospital between 1996 and 2003 were studied. The effects of age of patients, gender, stage of disease and treatment method on patients’ lifetime were assessed. For data analyses, survival analyses using Wavelet method and Log-rank test in R software were used. Nearly 25.3% of patients were female and the rest were male. Fourteen percent had surgery treatment and the rest had treatment without surgery. Three forth of patients died and the rest were censored. Almost 9.5% of patients were in early stage of disease, 53.7% in Locally Advance stage and 36.8% in Metastatic stage. The Hazard Function estimation in Wavelet method showed significant difference for stage of disease (P Only stage of disease had effect on hazard and most of patients diagnosed in the late stages of disease, which is possibly one of the most reasons for high hazard rate and low survival of these patients. Therefore, it seems to be necessary a public education about symptoms of disease by media and regular tests and screening for early diagnosis of this disease.