ABSTRACT
Background: One particular cause of death from breast cancer is distant metastasis. In this study, we calculate and compare diagnostic value of Mitotic Activity Index (MAI) and Ki-67 expression in predicting distant metastasis.Methods: Study was conducted in Sanglah Hospital from January 2017 to February 2019. All histopathology results from open biopsy are examined, thus MAI and Ki-67 values were obtained. We divided this into 2 groups: MAI high (≥20/HPF), low (<20/HPF) and Ki-67 high (≥20%) and low (<20%). We compared with distant metastasis event as gold standard, obtained from radiology examination. We count all diagnostic characteristics (sensitivity, specificity, positive and negative predictive value, accuracy, and likelihood ratio). We compared these diagnostic validities from data area under curve (AUC) with p value <0.005 considered to be statistically significant.Results: A total of 173 breast cancer patients were participated in this study, 92 of them had distant metastasis (53.2%) and 81 patients didn’t have any distant metastasis (46.8%). MAI had relative high specificity (82.7%) and Ki-67 had fair sensitivity values (69.6%). There are 0.08 point AUC differences between these two variables. With p value higher than 0.05 (0.06), it can be summarized that these two variables are not different significantly and statistically.Conclusions: There is not any statistically significant difference between these two markers in predicting distant metastasis in breast cancer. We hope other researcher interest into exploring more about these markers and their function.
ABSTRACT
To discuss the calculation methods under different sample size, used for diagnostic trials. The purpose of the diagnostic trial was to demonstrate the sensitivity and specificity of the new method. Equations and results were directly compared. Monte Carlo random simulation was used to validate the results. Sample size obtained from the sampling method was always smaller than from the target value method. Results from simulation showed that the target value method could offer more and larger power. The two sample size determination method showed essential differences of the results, suggesting that the investigator should choose appropriate method in accordance with the study design. If the hypothesis of study was to demonstrate the new diagnostic method which could meet the clinical requirements, only if the target value method provides enough statistical power.