The Intersection of Digital Pathology and Molecular & Genomic Testing Part 2

Curtis Stratman

In my last blog post, I talked about how the rise of molecular & genomic testing technologies is an opportunity for pathologists to elevate their role in cancer care, taking on the responsibility of being the primary integrator of a complex body of diagnostic knowledge. With these new technologies, however, come new challenges. The growing intricacy of pathology—a result of new technology and even deeper insights into our understanding of cancer—means an even greater potential increase in a pathologist’s workload.

This creates a clear need to provide pathologists with the tools to manage the growing challenges of workload, information, and communication.  Digital pathology represents an opportunity to connect the current routine work of anatomic pathologists, analyzing tissue samples on glass slides, with the full digital information flow around the patient. For the medical community to recognize this opportunity, we have to first understand how much we need pathologists to realize the potential value of precision medicine.

There are at least three specific functions where the pathologist’s skills are critical to precision medicine: determining the appropriate tests to order, ensuring quality samples are submitted for testing, and consulting on treatment options based on the test results.

Efficiently ordering the appropriate diagnostic tests requires a physician to develop an informed hypothesis of a patient’s condition as well as to be aware of the latest available testing tools. The former activity requires access to a broad base of patient clinical context. The latter activities require access to the continuously advancing set of knowledge coming from cancer research. Then there is an amount of detective skill required. As the final step in the diagnostic chain, pathologists are uniquely positioned and trained to be the diagnostic integrator for the cancer care pathway. They have all of the patient’s diagnostic results and physical tissue available to them to provide the final diagnostic opinion upon which the treating physician acts.

Molecular tests are particularly sensitive to the quality of the submitted sample. Obviously, the sample must have cancerous cells. Many of the tests also require a minimum number of sample cells and a minimum ratio of tumor to normal cells for the signal from the mutation under question to stand out significantly from the background. Current practices for performing this measurement has been observed to show a high deviation between the reported results and the gold standard, possibly causing false negative results.1  Research is also finding that many tumors are heterogeneous, meaning they are made up of multiple different types of cancer. In these cases, each cancer must be sampled and tested separately as each may have a distinct targeted treatment. Pathologists are the only physicians trained to manage tissue for testing. Their skill at visually identifying and differentiating cancers is also essential to extracting the right pieces of tissue for submission to molecular testing.

Precision Medicine ultimately requires that treatment options be individualized to the patient. As the research of cancers and genetics expands, the knowledge base of sub-types of cancers and the respective targeted therapies is constantly evolving. It is challenging for any physician to stay informed of the latest findings. Pathologists, through their focus on cancer and sub-specialization by organ system, have the opportunity to elevate their role as consultants providing evidence-based treatment recommendations    from all the diagnostic information available. This will enable oncologists to leverage the best treatment tools while focusing their time on management of the patient.

Implementing these practices into patient care requires the complete context of a single patient to be collected and analyzed in real time through the care pathway. At each step in the pathway, decision support tools need to drive action based on the latest research findings. To accelerate the translation of research findings into practice, the decision support rules need to be rapidly updateable with content. In this way, a digital pathology platform is the clear solution, both for our short term ability to leverage the immediate insights of new tools today while also gathering the data we need to glean new understandings tomorrow. The potential of these tools is exciting, but we cannot hope to leverage them without the expertise of a pathologist at the helm, leading diagnostic integration for the care pathway.

Sources:

Smits, Alexander JJ, et al.  The estimation of tumor cell percentage for molecular testing by pathologists is not accurate. Modern Pathology (2014) 27, 168–174.


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