AIMS: The purpose of the study is to evaluate histological measurement methods for quantitative assessment of the degree of tubular differentiation in breast cancer. METHODS AND RESULTS: We evaluated tubular differentiation in 20 cases of invasive breast cancer by four different assessment methods. Method 1 was the traditional subjective evaluation of the amount of malignant tubules in each sample. Method 2 evaluated the fraction of fields presenting tubular differentiation by registering the presence or absence of neoplastic tubular structures in each microscopic field. In method 3 the area fraction of malignant epithelial cells presenting tubular differentiation was assessed field-by-field and expressed as an average of the whole tumour area. Method 4 applied point counting for evaluating the fraction of malignant epithelial cells in tubular structures. By correlation and reproducibility analyses, method 1 was inferior to the other methods. Method 4 was accurate but too laborious and time-consuming for clinical use. Methods 2 and 3 were both efficient and reproducible and could be used interchangeably. With the time and effort used in the measurements taken into consideration method 2 was best applicable to clinical practice. CONCLUSION: Accurate evaluation of tubular differentiation in breast cancer is possible by defining the presence or absence of tubular differentiation in microscopic fields of a histological section. Assessment of the fraction of fields with tubular differentiation (FTD) is simple, unambiguous, objective and fast--even a large sample can be screened in less than 10 min. In our results, FTD has clear advantages over subjective or point counting-based evaluation methods of tubular differentiation.
AIMS: The purpose of the study is to evaluate histological measurement methods for quantitative assessment of the degree of tubular differentiation in breast cancer. METHODS AND RESULTS: We evaluated tubular differentiation in 20 cases of invasive breast cancer by four different assessment methods. Method 1 was the traditional subjective evaluation of the amount of malignant tubules in each sample. Method 2 evaluated the fraction of fields presenting tubular differentiation by registering the presence or absence of neoplastic tubular structures in each microscopic field. In method 3 the area fraction of malignant epithelial cells presenting tubular differentiation was assessed field-by-field and expressed as an average of the whole tumour area. Method 4 applied point counting for evaluating the fraction of malignant epithelial cells in tubular structures. By correlation and reproducibility analyses, method 1 was inferior to the other methods. Method 4 was accurate but too laborious and time-consuming for clinical use. Methods 2 and 3 were both efficient and reproducible and could be used interchangeably. With the time and effort used in the measurements taken into consideration method 2 was best applicable to clinical practice. CONCLUSION: Accurate evaluation of tubular differentiation in breast cancer is possible by defining the presence or absence of tubular differentiation in microscopic fields of a histological section. Assessment of the fraction of fields with tubular differentiation (FTD) is simple, unambiguous, objective and fast--even a large sample can be screened in less than 10 min. In our results, FTD has clear advantages over subjective or point counting-based evaluation methods of tubular differentiation.