Influence of ethnicity on survival of breast cancer patients in Turkey.

ABSTRACT

BACKGROUND: Kurdish women with breast cancer have more unfavorable prognostic factors than their Turkish and Arab counterparts. However, the effects of these factors on breast cancer survival among these ethnic groups remain unclear. We therefore investigated the impact of ethnicity on survival in breast cancer patients in Turkey. MATERIALS AND METHODS: Ethnicity, age, stage at diagnosis, tumor characteristics, treatments given (surgery, chemotherapy, radiotherapy and hormone therapy), and survival times were recorded. Kaplan- Meier analysis was used to estimate the overall survival times and survival plots. Log-rank test was used to compare the survival curves. RESULTS: Of the 723 breast cancer patients included in the study, 496 (68.7%) were Turkish, 189 (26.2%) were Kurdish, 37 (5.1%) were Arabic and 1 was Armenian. Kurdish women with breast cancer had larger tumor sizes and higher rates of hormone receptor negative tumors than Turkish and Arab patients. Mean follow-up time was 118.4 [95% Confidence Interval (CI) 95.4-141.3] months, and it was 129.9 (95% CI 93.7-166.2), 124.2 (95% CI 108.4-140.1) and 103.1 (95% CI 85.9-120.4) months for Turkish, Arabic and Kurdish patients, respectively. CONCLUSIONS: Kurdish ethnicity is associated with higher rates of hormone receptor negative and triple-negative tumors and with worse survival. Clinical and epidemiological research is warranted to elucidate reasons underlying overall survival, variations in tumor biology, differences in treatment responsiveness, and effects of social factors among ethnic groups in Turkey.