The role of the pathologist in the decision-making process

During the last two decades the pathological classification of breast carcinoma has evolved rapidly. Starting from the pure assessment of conventional morphology, it has gradually been integrated with immunophenotypic evaluation of the hormone receptor, HER2, and Ki67 status. In addition, molecular genetic testing (mostly by fluorescence in situ hybridisation, FISH) for Her2 immunohistochemically ‘equivocal’ cases has become a standard. Pathological evaluation of breast specimens has shifted rapidly from a mere diagnostic process, aimed at establishing the biological potential of a breast ‘lump’, to a far more complex integration of diagnostic, prognostic and predictive parameters. The current landscape has been further complicated by the relatively recent introduction of a ‘molecular’ classification of breast cancer [1]. Since then pathologists and clinicians have struggled in the attempt to translate (or maybe to force) the classic morphological approach into a molecularly based scheme (Table 1). Whatever the approach, the role played by the pathologist in the clinical decision-making process has never been so central. Establishing the correct diagnosis, as well as accurately evaluating key prognostic/predictive biomarkers, represent the core of the breast cancer pathology report. Even acknowledging the current complexity of personalised treatments, it is broadly accepted that the information mandatory for inclusion in the pathology report represents a milestone for optimal therapeutic planning.