A study of conventional histological parameters in excision specimens of breast cancer over a 7 year period and association with immunohistochemical categories

Background Along with conventional histological examination, immunohistochemistry (IHC) is a useful adjunct to assessment of a breast cancer excision specimen. Previous studies have shown differences in behavior of neoplasms depending on their histopathological as well as immunohistochemical categories; in particular, triple negative breast cancers (on IHC) show the worst prognosis. Objectives To find association, if any, within conventional histopathological characteristics (size, grade, stage, mitotic count, desmoplasia, dense inflammatory infiltrate, lymphovascular invasion) and between the conventional parameters and immunohistochemical categories of breast cancer, in both primary and post neo adjuvant chemotherapy (NACT) specimens. Methods 177 breast cancer excision specimens examined over last 7 years were assessed retrospectively, their histopathological parameters were recorded. In cases where immunohistochemistry was performed (N=108) the specimen was placed in one of the immunohistochemical categories: Luminal A, Luminal B, Her2 and Triple negative cancers. The data was then analysed by standard statistical methods. Results No statistically significant association was found between the histopathological parameters and IHC category was. However, a strong correlation was seen between lymphovascular invasion within the primary tumor and increasing lymph node involvement. There was also a reduction in ER and PR expression in neoplasms post NACT, while HER2 expression remained largely unchanged. Conclusion There might be additional genetic subtypes underlying the immunohistochemical phenotypes which determine the morphological characteristics of the neoplasm.