Correlation between the proportion of breast volume involved by locally advanced tumors and invasion of the skin and posterior structures

AIM: To evaluate any differences between the percentages of involved breast volume, pathologic attributes, and tumor marker expression of T3 and T4a-c tumors in locally advanced breast cancers (BC). METHODS: All patients with T3N > 0 and T4a-c BC without evidence of distant metastasis (M0), presenting to the Breast Clinic from 1980 to 2010, were examined to determine whether their BC’s involved ≥ 50% of their breast volumes, defined by gross replacement of at least one hemisphere. Core needle biopsy or post-mastectomy specimens from tumors involving a known percent of breast volume were evaluated for: (1) pathological grades and lympho-vascular invasion (LVI); (2) hormone receptor (ER/PR) expression > 0; and (3) epidermoid growth factor 2 (her2) over-expression (3+) by immune-histochemical staining or fluorescent in situ hybridization. RESULTS: The data base included 98 patients with T3N> 0 M0 and 120 with T4a-c, any N disease, M0 disease. T3 tumor masses involved 50% or more of the breast in 23/98 (24%), and T4a-c tumors 65/120 (54%) (P < 0.001). Only 1% of T3 tumors and 23% of T4a-c tumors presented with total breast replacement. There were no significant differences between the pathological attributes and marker expression of the T3 and T4a-c tumors. CONCLUSION: These data suggest that erosion of the overlying skin or underlying chest wall by some BC may be due to neglect and delay, rather than inherent biological aggressiveness.