Relationship between the morphological and biological characteristics of intraductal components accompanying invasive ductal breast carcinoma and patient age

We divided 324 cases with invasive ductal breast carcinoma into three age g roups, and investigated the differences in proliferative activity and exten sion of the intraductal components among the age cohorts. Proliferative act ivity was expressed as the number of MIB 1-positive nuclei per 1000 cancer cells in the intraductal components (MLI), and the intraductal component ex tension farthest from the invasive focus was defined as the maximum distanc e of ductal spread (MXDS). Moreover, analyses were conducted for three grad e types, classified according to the classification system of ductal carcin oma in situ. The under-40 age group had significantly higher MXDS values th an the other two age groups (p = 0.0280), and this trend was more marked in those with the non-high grade without necrosis type (p = 0.0045). The unde r-40 age group had higher MLIs, but the differences did not reach statistic al significance (p = 0.0793). In regard to those with the high grade type, the under-40 age group had significantly higher MLIs than the other two age groups (p = 0.0269), and this trend was not significant in the cases with any other grade types. Associations between the age group and the margin st atus of the lumpectomy specimens were investigated in the 143 cases in whic h breast conserving surgery was tried. The under-40s had a significantly hi gher margin-positive rate in their lumpectomy specimens than the other two age groups (p = 0.0362), and this trend was also seen in the groups with th e non-high grade without necrosis type (p = 0.0256). These results confirm the importance of considering patient age when designing surgical procedure s for breast conserving therapy.