Black Hispanic and Black Non-Hispanic Breast Cancer Survival Data Analysis with Half-normal Model Application

Abstract

<b>Background:</b> Breast cancer is the second leading cause of cancer death for women in the United States.Differences in survival of breast cancer have been noted among racial and ethnic groups, but the reasons forthese disparities remain unclear. This study presents the characteristics and the survival curve of two racial andethnic groups and evaluates the effects of race on survival times by measuring the lifetime data-based half-normalmodel. Materials and <br/><b>Methods</b>: The distributions among racial and ethnic groups are compared using femalebreast cancer patients from nine states in the country all taken from the National Cancer Institute’s Surveillance,Epidemiology, and End Results cancer registry. The main end points observed are: age at diagnosis, survivaltime in months, and marital status. The right skewed half-normal statistical probability model is used to showthe differences in the survival times between black Hispanic (BH) and black non-Hispanic (BNH) female breastcancer patients. The Kaplan-Meier and Cox proportional hazard ratio are used to estimate and compare therelative risk of death in two minority groups, BH and BNH. <br/><b>Results</b>: A probability random sample method wasused to select representative samples from BNH and BH female breast cancer patients, who were diagnosed duringthe years of 1973-2009 in the United States. The sample contained 1,000 BNH and 298 BH female breast cancerpatients. The median age at diagnosis was 57.75 years among BNH and 54.11 years among BH. The results ofthe half-normal model showed that the survival times formed positive skewed models with higher variability inBNH compared with BH. The Kaplan-Meir estimate was used to plot the survival curves for cancer patients; thistest was positively skewed. The Kaplan-Meier and Cox proportional hazard ratio for survival analysis showedthat BNH had a significantly longer survival time as compared to BH which is consistent with the results of thehalf-normal model. <br/><b>Conclusions</b>: The findings with the proposed model strategy will assist in the healthcarefield to measure future outcomes for BH and BNH, given their past history and conditions. These findings mayprovide an enhanced and improved outlook for the diagnosis and treatment of breast cancer patients in theUnited States.