In the past several years, the College of American Pathologists and the American Society of Clinical Oncology have collaborated to create new laboratory guidelines for breast cancer predictive factor testing. Although testing guidelines are not new to the clinical laboratory, the development of national standards for testing tissue samples-first for HER2 and then hormone receptors - represents a significant step forward for pathology labs.
These guidelines are truly game-changing in the effort to ensure that each patient is getting the most accurate diagnostic assessment and treatment plan. They address all three phases of the test cycle (preanalytic, analytic, and postanalytic) and have resulted in significant improvements in laboratory performance nationwide. Pathologists, oncologists, and surgeons are now much more mindful of the variables that lead to false-positive and false-negative test results and are more aware of what specimen types are most appropriate for a given patient.
We actively participate in multidisciplinary treatment conferences, and research underscores the need for a true team approach to cancer care. Several studies have shown that changes in treatment recommendations occur in about half of breast cancer patients who are presented at tumor boards.1,2 In one such study, changes in pathology interpretation occurred in 29 percent of patients presented at a multidisciplinary tumor board; nine percent had a change in clinical management solely as a result of pathologic reinterpretation.2
In my experience, cooperation among members of the patient care team is also important in explaining discrepancies in diagnostic tests. For example, a 52-year-old woman at our institution had a 2 cm invasive breast carcinoma with atypical medullary features. Immunohistochemical staining showed that 20 percent of the tumor cells were strongly reactive for estrogen receptor, and the tumor was reported as ER positive. Oncotype DX testing was subsequently ordered, but the quantitative single gene assay for ER was reported as negative.
The oncologist seeing this patient was rightfully concerned about the discrepancy. Review of the slides showed that lymphocytes comprised about 75 percent of the tumor mass. Since the Oncotype assay assesses all of the cells in the tissue sample, we determined that the gene assay was almost certainly a false negative due to dilution of gene signal by the admixed non-neoplastic cells. Data alone, without this type of collaboration cannot always get to the truth.
It is our job as pathologists to manage and help interpret the increasing deluge of genomic and other personalized laboratory data to help ensure precise, effective treatment. We facilitate the integration and continuity of patient data across the patient care team, ensuring that we can all get to the right diagnosis.
As cancer treatments improve, so too will the number of cancer survivors increase. It is incumbent on us, the patients' care team, to come up with innovative solutions and work together to provide accurate diagnostic information and precision diagnoses to help patients lead healthier lives. I am quite sure that we will find the result to be the optimal patient care for which we all strive.
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