Obesity Status among Breast Cancer Patients Based on the Korean Obesity Index Standard Reference in the Aging Community

ABSTRACT

Purpose@#Obesity and age are known risk factors for breast cancer. However, as these factors tend to be reported together, their individual contributions are unclear; age might confound the impact of obesity on outcomes. This study investigated the status of obesity in patients with breast cancer and its correlation with either clinical characteristics or overall survival, using the Korean obesity index standard reference (KOISR) which stratified by age, and matched with outcomes of the local general population. @*Methods@#We conducted a single-center retrospective study between January 2014 and December 2018. A total of 429 patients diagnosed with and treated for breast cancer were categorized according to the World Health Organization (WHO) body mass index (BMI) classification for Asian populations or KOISR. We examined the impact of the KOISR on the current status of obesity, and survival outcomes with the log-rank test. @*Results@#In a sample of 418 patients, the distribution of obese, normal, and low BMI was 143 (34.2%), 266 (63.6%), and 9 (2.2%) patients, respectively. When categorized by the KOISR, 52.6% of all patients placed above the 75th percentile; advanced breast cancer diagnosis was likely in this group (p=0.030). BMI correlated with age (19.4% of women with less than 50 years and 45.4% of women aged 50 years and above were obese; p=0.001). No significant difference in overall survival (p=0.340) was observed between KOISR score-based groups (<75th percentile vs. ≥75th percentile), stratified by stage. @*Conclusion@#Adjusted with a community and age (KOISR), patients with breast cancer have a relatively higher BMI than the general population in a similar community and generation. Women with a high KOISR score were also more likely to have advanced breast cancer than non-obese women. Nevertheless, high BMI was not a major factor affecting survival in this study.