Estimation of Hazard Function and its Associated Factors in Gastric Cancer Patients using Wavelet and Kernel Smoothing Methods

Background and
Objectives: Increase of mortality rates of gastric cancer in Iran and the world in recentyears reveal necessity of studies on this disease. Here, hazard function for gastric cancer patients was estimatedusing Wavelet and Kernel methods and some related factors were assessed. Materials and
Methods: Ninetyfivegastric cancer patients in Fayazbakhsh Hospital between 1996 and 2003 were studied. The effects of age ofpatients, gender, stage of disease and treatment method on patient’s lifetime were assessed. For data analyses,survival analyses using Wavelet method and Log-rank test in R software were used.
Results: Nearly 25.3% ofpatients were female. Fourteen percent had surgery treatment and the rest had treatment without surgery.Three fourths died and the rest were censored. Almost 9.5% of patients were in early stages of the disease, 53.7%in locally advance stage and 36.8% in metastatic stage. Hazard function estimation with the wavelet methodshowed significant difference for stages of disease (P<0.001) and did not reveal any significant difference forage, gender and treatment method.
Conclusion: Only stage of disease had effects on hazard and most patientswere diagnosed in late stages of disease, which is possibly one of the most reasons for high hazard rate and lowsurvival. Therefore, it seems to be necessary a public education about symptoms of disease by media and regulartests and screening for early diagnosis.