Health care providers may be unfamiliar with the workings of the pathology laboratory. The delivery of a specimen to the pathology laboratory initiates a complex series of events resulting in a pathologic diagnosis/interpretation. The following section reviews the importance and key objectives in the pathologic evaluation of tissue and provides information on the types and members of the pathology laboratory.
Importance of pathologic examination
The diagnosis of cancer is not conclusively established, nor safely assumed, in the absence of a tissue diagnosis, nor should definitive therapy for cancer, with rare exception, be undertaken. Policies supporting this practice are written into the bylaws of most hospitals and are regularly monitored by hospital tissue committees and accrediting agencies.
The goal of pathology examination of tissue is to provide accurate, specific and sufficiently comprehensive diagnoses to enable the treating physician to develop an optimal plan of treatment. There are hundreds of varieties tumors, most with characteristic biology, that require accurate diagnosis by pathologists. Data on markers with prognostic and predictive significance are also routinely incorporated into pathology reports, allowing individualized treatment plans for patients. It is not only important to obtain sufficient tissue for a specific diagnosis of malignancy, but for many malignancies, additional tissue is required for prognostic and predictive ancillary studies.
While some have postulated that we are moving toward a gene/mutation driven categorization of tumors replacing disease site clinics and treatment planning (e.g., PIK3CA mutated carcinomas instead of “ovarian” cancer or “breast” cancer), data is accumulating that histology, morphology, disease site location and microenvironment in addition to genomic changes are still important factors in understanding the disease biology for treatment planning.