Prognostic significance of scoring system based on histological heterogeneity of invasive ductal carcinoma for node-negative breast cancer patients

This study aimed to determine the prognostic significance of histological scoring system based on heterogeneity of invasive ductal carcinoma, for node-negative breast cancer patients. We studied 108 patients of node-negative invasive ductal carcinoma with invasive tumor >5 mm. Histological score of each patient was evaluated based on histological subtype of invasive ductal carcinoma and pattern of. its heterogeneity. Score of each subtype was defined as follows; papillotubular carcinoma: score 1, solid-tubular carcinoma: score 2 and scirrhous carcinoma: score 3. The existence of histological heterogeneity was examined, and corresponding score was doubled in a pure case and scores of two dominant subtypes were summed in a composite case. Overall survival curves defined by sores were drawn by Kaplan-Meier method and the difference in survival rate was evaluated by log-rank test. The most significant difference of overall survival was recognized between low score group (scores 2, 3 and 4) and high score group (scores 5 and 6) (p < 0.001). In addition, multivariate analysis confirmed that only histological score was an independent prognostic factor. These results suggested that assessment of histological heterogeneity of invasive ductal carcinoma could serve as independent potent prognostic factor for node-negative invasive ductal carcinoma of the breast, and this method might be useful to decide indication of postoperative adjuvant chemotherapy.