Ki-67 as a Predicting Factor of Neoadjuvant Chemotherapy Clinical Response for Local Advanced Breast Cancer in Indonesia

Background: Breast cancer is one of the most common health problems in Indonesia where 42.7% of patients have been diagnosed with Local Advanced Breast Cancer (LABC). Neoadjuvant chemotherapy (NAC) is aimed to decrease the tumor size to be operable and decrease mortality. Ki-67 is highly expressed in the cell proliferation phase, while chemotherapy agents work effectively by targeting this proliferation. This study evaluates the utility of Ki-67 in LABC patients of the Asian-Indonesian population.
Methods: This is a retrospective cohort study. Ki-67 data was from the medical record based on the immunohistochemistry staining with >20% cut off point. Clinical response was measured based on the WHO criteria after the third chemotherapy cycle.
Result: The majority of subjects in this study were 50 years old, with T4 tumor size, N1 lymph node involvement, NST histopathological type, grade 2, ER-positive, PR-positive, HER2-negative, high Ki67 expression, and luminal B subtype. 52.1% of all subjects showed ‘poor’ clinical responses to NAC. There was no significant association between subjects’ characteristics and the NAC Clinical response. Moreover, there was no significant association between Ki-67 and chemotherapy clinical response (p=1).
Conclusion: There is no statistically significant association between Ki-67 expression and NAC clinical response of LABC patients in Indonesia.