Breast cancer distribution and survival among Buddhist and Muslim women in southern Thailand

Objective: Thailand is undergoing a period of rapid economic growth, which has led to an epidemiologic transition from infectious to chronic diseases such as cancer. Preliminary research shows a difference in rates of breast cancer incidence and mortality between Buddhist and Muslim women in southern Thailand. This study examines differences in breast cancer and potential explanations for this disparity. Methods: Demographic, diagnostic, and outcome data from breast cancer patients diagnosed from 2001-2015 were collected from a population-based cancer registry in southern Thailand and matched with formalin-fixed paraffin-embedded blocks from Songklanagarind Hospital. This region was selected due to the relatively high proportion of Muslim women. Of 424 cases selected, 369 were Buddhist and 55 were Muslim. Formalin-fixed paraffin-embedded blocks were sent to Michigan Medicine and histological and subtype analyses were performed by two pathologists. Statistical analysis was performed in RStudio using chi-square tests of independence, logistic regression, and Cox proportional hazards models. Results: Muslim women were generally diagnosed at a younger age than Buddhist women (Muslim mean: 46.6 years, Buddhist mean: 52.7 years) and with later stage cancers (Muslim: 36% stage 3 and 14% stage 4, Buddhist: 20% stage 3 and 8% stage 4). Buddhist and Muslim women had similar distributions of Luminal A and B subtypes, but Muslim women were more likely to be diagnosed with Triple Negative breast cancer (Muslim: 30%, Buddhist: 18%), the histological subtype with the worst prognosis. Invasive ductal carcinoma was most common in both groups, but Buddhists had more heterogeneity in subtypes. There were no significant differences in tumor histology or subtype by religion. Conclusions: These analyses show differences in the distribution of breast cancer between Buddhist and Muslim women. Muslim women are diagnosed younger with later stage breast cancers, and with histological differences, which generally lead to lower survival rates. Lack of statistical significance may be due to small sample size, necessitating further studies. Citation Format: Kali Defever, Katie M. Rentschler, Ana Khazan, Elizabeth Pinkerton, Shama Virani, Hutcha Sriplung, Judy Pang, Celina G. Kleer, Carlos F. Mendes de Leon, Justin A. Colacino, Laura S. Rozek. Breast cancer distribution and survival among Buddhist and Muslim women in southern Thailand [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4219.