Use of test
Purpose:
Mutations in the EGFR (epidermal growth factor receptor) gene can guide the choice of therapy in patients with non-small cell lung cancer (NSCLC). Clinically relevant mutations occur in exons 18, 19, 20 and 21 of the gene and include T790M.
This is a test for mutations in the EGFR gene only. EGFR plus other genes are included in our full FIND-IT panel and focussed panel for lung cancer. We also provide a separate assay for EGFR FISH. The EGFR FISH test is useful in gliomas; it does not have a role in the management of lung cancer.
Utility:
The presence of specific EGFR mutations in NSCLC indicates sensitivity or resistance to EGFR tyrosine kinase inhibitor (TKI) therapies.
The test can be requested to determine if the requirements relating to EGFR gene status for access to erlotinib, gefitinib or afatinib under the Pharmaceutical Benefits Scheme (PBS) are fulfilled.The test is also applicable for tumour tissue that is derived from a new sample from a patient with locally advanced (Stage IIIb) or metastatic (Stage IV) NSCLC, who has progressed on or after treatment with an EGFR TKI. In such incidences, the test can be requested to determine if the requirements relating to EGFR T790M gene status for access to osimertinib under the PBS are fulfilled.
Ethical considerations:
This is an assay for non-heritable mutations. It does not raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient.
Methodology:
The Idylla EGFR Mutation Test is used to detect the presence of several different mutations in the EGFR gene.
Requesting the test
Ordering:
This test is usually requested by a surgeon, oncologist or the pathologist providing the initial histopathology report. Please use the specific request form (see link below).
Request form:
Download the somatic mutation request form.
Sample required:
Formalin-fixed, paraffin embedded tissue (FFPE) - 15 sections of 4 uM thickness, dried overnight at 37°C onto charged/coated slides.
Special instructions:
Please stain the first section with H&E, and label each slide with patient and block identifiers. Label the unstained sections sequentially (slides 2-15). The request should be accompanied by the specific somatic mutation request form (above) and a copy of the original histopathology report.
Turnaround time:
5-10 business days.
Price:
This test has a Medicare rebate which, subject to the requirements of the Medicare descriptor being met, may cover all or part of the cost.
The MBS item number is 73337 for access to erlotinib, gefitinib or afatinib.The MBS item number is 73351 for access to osimertinib.
Rebate:
The Medicare details, including descriptor and schedule fee, are listed under MBS item 73337 and MBS item 73351.