When an oncologist anticipates an initial sample (e.g., cytology) will likely have insufficient tissue for NGS testing, they proactively initiate a biopsy of a second site with interventional radiology. This parallel-path approach avoids waiting for the first test to fail, significantly reducing time to diagnosis and treatment.
To prevent exhausting small tissue samples, a pathology lab physically splits incoming biopsies into two cassettes. A small portion is used for initial diagnostic workups like immunohistochemical stains, while the bulk of the specimen is reserved in a separate cassette specifically for molecular testing, guaranteeing tissue adequacy.
To maximize advantages, an in-house lab consciously selected a different NGS testing platform than major external vendors. This strategic choice not only reduced tissue sample requirements but also offered a faster turnaround time due to the underlying technology, creating a distinct competitive advantage beyond mere proximity.
When the FDA approves a new biomarker-linked therapy, an in-house pathology lab actively queries its historical database of all prior NGS tests to identify past cases with the relevant genetic alteration. They then proactively contact the oncologists for these patients, uncovering new treatment options that were previously unavailable.
A lab implements rigorous quality control by logging all in-house NGS results. When a patient later has a sample sent to an external vendor for a different test (e.g., liquid biopsy), the lab cross-references the new results with their original findings to ensure no mutations were missed and to retroactively validate their own accuracy.
For certain therapies like Enhertu, eligibility is based on immunohistochemistry (IHC), not NGS. Labs must run HER2 IHC in parallel because NGS, as a population-based test, can miss intratumoral heterogeneity (small clusters of positive cells) that IHC can detect, thus identifying more eligible patients for targeted therapy.