Q: Pathologists are faced with the need to set up additional lab tests routinely. Immunotherapy for cancer is the current rage. How does a pathologist decide whether and how to offer a new test such as PD-L1 Expression Testing?
A: The decision to introduce a new test or remove an old test is not as easy as one would think. There are many variables that must be taken into consideration. Concerning your question i.e. when to introduce a “new” test that may be used to direct therapy in a patient with cancer is an especially important task for the pathologist.
In my own experience using your example the subject would probably arise at a tumor board or multidisciplinary conference. This is setting where pathologists, oncologists, radiologists, surgeons and other medical specialists discuss possible or already identified cancer patients for input and recommendations on evaluation, more specific diagnostic information, treatment options and follow-up plans.
Today with the rapidly expanding complexities resulting from the introduction and availability of new biomarkers be they genomic, proteomic etc. that aid in diagnostic, prognostic and/or therapeutic decisions the burden of proof to introduce a test into your lab is very high. The more so if the “claims” being made are the specific biomarker results which are important and maybe critical in enhancing patient outcomes. The point is that the initial but critical decision of whether a new test should be available and introduced into your lab will be a team effort with input from users of test (the utility) and those responsible for ensuring the test can in fact be performed accurately in your specific lab environment (your validation).
The FDA has already approved PD-LD1. Its value is backed up by numerous clinical studies published in peer-reviewed journals, suggesting that “at this time” having the test results for PD-L1 are important for the treating physician to have in a timely manner.
Now the question is do you send the test request out to another laboratory or introduce it into your own? There are many questions to be answered by lab director in order to make that determination. A short example list of important questions below in no specific order:
What would the number of requests for PD-L1 be in your lab?
Are these numbers high enough to ensure on-going experience in performing test?
Does your lab have skilled staff that can be trained to perform test?
Do you have the resources to ensure your staff have the time to introduce, validate and ensure ongoing quality control of the test?
What will be the costs to provide the test in-house or sent to outside lab?
What is turn-around-time expected from your ordering physicians?
Do you have ability to meet their expectations?
If volume is questionable can an outside lab meet the turn-around time expectations?
What process would you use to select an outside testing lab?
If you decide to perform test what method would you select?
What process would you use to validate, maintain quality control and select appropriate ongoing proficiency and competency testing as per CLIA?
The answers to these questions and others depending on your clinical setting would help you and your colleagues determine if the test for PD-L1 should be performed in-house or sent to another laboratory.
Important to remember: this decision needs to be revisited depending on changes to the answers to above questions occurring over time.