The grades of recommendation (A-D) and the strength of evidence (I-IV) are defined at the end of the "Major Recommendations" field.
SECTION I: When Should Molecular Testing of Lung Cancers Be Performed?
Question 1: Which Patients Should Be Tested for Epidermal Growth Factor Receptor (EGFR) Mutations and Anaplastic Lymphoma Kinase (ALK) Rearrangements?
1.1a: Recommendation. EGFR molecular testing should be used to select patients for EGFR-targeted tyrosine kinase inhibitor (TKI) therapy, and patients with lung adenocarcinoma should not be excluded from testing on the basis of clinical characteristics.
1.1b: Recommendation. ALK molecular testing should be used to select patients for ALK-targeted TKI therapy, and patients with lung adenocarcinoma should not be excluded from testing on the basis of clinical characteristics. Evidence Grade: EGFR A; ALK: B
1.2: Recommendation. In the setting of lung cancer resection specimens, EGFR and ALK testing is recommended for adenocarcinomas and mixed lung cancers with an adenocarcinoma component, regardless of histologic grade. In the setting of fully excised lung cancer specimens, EGFR and ALK testing is not recommended in lung cancers that lack any adenocarcinoma component, such as "pure" squamous cell carcinomas, "pure" small cell carcinomas, or large cell carcinomas lacking any immunohistochemistry (IHC) evidence of adenocarcinoma differentiation. Evidence Grade: EGFR and ALK: A
1.3: Recommendation. In the setting of more limited lung cancer specimens (biopsies, cytology) where an adenocarcinoma component cannot be completely excluded, EGFR and ALK testing may be performed in cases showing squamous or small cell histology but clinical criteria (e.g., young age, lack of smoking history) may be useful in selecting a subset of these samples for testing. Evidence Grade: EGFR and ALK: A
1.4: Recommendation. To determine EGFR and ALK status for initial treatment selection, primary tumors or metastatic lesions are equally suitable for testing. Evidence Grade: EGFR and ALK: B
1.5: Expert consensus opinion. For patients with multiple, apparently separate, primary lung adenocarcinomas, each tumor may be tested but testing of multiple different areas within a single tumor is not necessary.
Question 2: When Should a Patient Specimen Be Tested for EGFR Mutation or ALK Rearrangement?
2.1a: Recommendation. EGFR mutation testing should be ordered at the time of diagnosis for patients presenting with advanced-stage disease (stage IV according to the 7th edition tumor, node, metastasis [TNM] staging system) who are suitable for therapy or at time of recurrence or progression in patients who originally presented with lower-stage disease but were not previously tested.
2.1b: Suggestion. ALK rearrangement testing should be ordered at the time of diagnosis for patients presenting with advanced-stage disease (stage IV according to the 7th edition TNM staging system) who are suitable for therapy or at time of recurrence or progression in patients who originally presented with lower-stage disease but were not previously tested. Evidence Grade: EGFR: A; ALK: C
2.2a: Expert consensus opinion. EGFR testing of tumors at diagnosis from patients presenting with stage I, II, or III disease is encouraged but the decision to do so should be made locally by each laboratory, in collaboration with its oncology team.
2.2b: Expert consensus opinion. ALK testing of tumors at diagnosis from patients presenting with stage I, II, or III disease is encouraged, but the decision to do so should be made locally by each laboratory, in collaboration with its oncology team.
2.3 Recommendation. Tissue should be prioritized for EGFR and ALK testing. Evidence Grade: EGFR: A; ALK: B
Question 3: How Rapidly Should Test Results Be Available?
3.1: Expert consensus opinion. EGFR and ALK results should be available within 2 weeks (10 working days) of receiving the specimen in the testing laboratory.
3.2: Expert consensus opinion. Laboratories with average turnaround times beyond 2 weeks need to make available a more rapid test—either in-house or through a reference laboratory—in instances of clinical urgency.
3.3: Expert consensus opinion. Laboratory departments should establish processes to ensure that specimens that have a final histopathologic diagnosis are sent to outside molecular pathology laboratories within 3 working days of receiving requests and to intramural molecular pathology laboratories within 24 hours.
SECTION II: How Should EGFR Testing Be Performed?
Question 4: How Should Specimens Be Processed for EGFR Mutation Testing?
4.1: Expert consensus opinion. Pathologists should use formalin-fixed, paraffin-embedded (FFPE) specimens or fresh, frozen, or alcohol-fixed specimens for polymerase chain reaction (PCR)-based EGFR mutation tests. Other tissue treatments (e.g., acidic or heavy metal fixatives, or decalcifying solutions) should be avoided in specimens destined for EGFR testing.
4.2: Expert consensus opinion. Cytologic samples are also suitable for EGFR and ALK testing, with cell blocks being preferred over smear preparations.
Question 5: What Are the Specimen Requirements for EGFR Testing?
5.1: Expert consensus opinion. Pathologists should determine the adequacy of specimens for EGFR testing by assessing cancer cell content and deoxyribonucleic acid (DNA) quantity and quality.
5.2: Expert consensus opinion. Each laboratory should establish the minimum proportion and number of cancer cells needed for mutation detection during validation.
5.3: Expert consensus opinion. A pathologist should assess the tumor content of each specimen and either perform, or guide a trained technologist to perform, microdissection for tumor cell enrichment as needed.
Question 6: How Should EGFR Testing Be Performed?
6.1: Recommendation. Laboratories may use any validated EGFR testing method with sufficient performance characteristics. Evidence Grade: B
6.2: Expert consensus opinion. Laboratories should use EGFR test methods that are able to detect mutations in specimens with at least 50% cancer cell content, although laboratories are strongly encouraged to use (or have available at an external reference laboratory) more sensitive tests that are able to detect mutations in specimens with as little as 10% cancer cells.
6.3: Expert consensus opinion. Clinical EGFR mutation testing should be able to detect all individual mutations that have been reported with a frequency of at least 1% of EGFR-mutated lung adenocarcinomas.
6.4: Recommendation. Immunohistochemistry for total EGFR is not recommended for selection of EGFR TKI therapy. Evidence Grade: A
6.5: Recommendation. EGFR copy number analysis (i.e., fluorescence in situ hybridization [FISH] or chromogenic in situ hybridization [CISH]) is not recommended for selection of EGFR TKI therapy. Evidence Grade: B
Question 7: What Is the Role of KRAS Analysis in Selecting Patients for Targeted Therapy With EGFR TKIs?
7.1: Recommendation. KRAS mutation testing is not recommended as a sole determinant of EGFR TKI therapy. Evidence Grade: B
Question 8: What Additional Testing Considerations Are Important in the Setting of Secondary or Acquired EGFR TKI Resistance?
8.1: Recommendation. If a laboratory performs testing on specimens from patients with acquired resistance to EGFR kinase inhibitors, such tests should be able to detect the secondary EGFR T790M mutation in as few as 5% of cells. Evidence Grade: B
SECTION III: How Should ALK Testing Be Performed?
Question 9: What Methods Should Be Used for ALK Testing?
9.1: Recommendation. Laboratories should use an ALK FISH assay using dual-labeled break-apart probes for selecting patients for ALK TKI therapy; ALK immunohistochemistry, if carefully validated, may be considered as a screening methodology to select specimens for ALK FISH testing. Evidence Grade: B
9.2: Recommendation. Reverse transcription-polymerase chain reaction (RT-PCR) is not recommended as an alternative to FISH for selecting patients for ALK inhibitor therapy. Evidence Grade: B
9.3: Expert consensus opinion. A pathologist should be involved in the selection of sections for ALK FISH testing, by assessing tumor architecture, cytology, and specimen quality.
9.4: Expert consensus opinion. A pathologist should participate in the interpretation of ALK FISH slides, either by performing the analysis directly or by reviewing the interpretations of cytogeneticists or technologists with specialized training in solid tumor FISH analysis.
9.5: Expert consensus opinion. Testing for secondary mutations in ALK associated with acquired resistance to ALK inhibitors is not currently required for clinical management.
SECTION IV: Should Other Genes Be Routinely Tested in Lung Adenocarcinoma?
Question 10: Are Other Molecular Markers Suitable for Testing in Lung Cancer?
10.1a: Recommendation. Testing for EGFR should be prioritized over other molecular markers in lung adenocarcinoma.
10.1b: Suggestion. After EGFR testing, testing for ALK should be prioritized over other proposed molecular markers in lung adenocarcinoma, for which published evidence is insufficient to support testing guideline development at the present time. Evidence Grade: EGFR: A; ALK: C
SECTION V: How Should Molecular Testing of Lung Adenocarcinomas Be Implemented and Operationalized?
Question 11: Must All Adenocarcinomas Be Tested for Both EGFR and ALK?
11.1: Expert consensus opinion. Laboratories may implement testing algorithms to enhance the efficiency of molecular testing of lung adenocarcinomas, provided the overall turnaround time requirements are met.
Question 12: How Should EGFR and ALK Results Be Reported?
12.1: Expert consensus opinion. EGFR mutation testing reports and ALK FISH reports should include a results and interpretation section readily understandable by oncologists and by nonspecialist pathologists.
Question 13: How Should EGFR and ALK Testing Be Validated?
13.1: Expert consensus opinion. EGFR and ALK testing validation should follow the same guidelines as for other molecular diagnostics and FISH tests.
Question 14: How Should Quality Assurance Be Maintained?
14.1: Expert consensus opinion. Laboratories should follow similar quality control and quality assurance policies and procedures for EGFR and ALK testing in lung cancers as for other clinical laboratory assays. In particular, laboratories performing EGFR and ALK testing for TKI therapy should enroll in proficiency testing, if available.
Definition of Grades of Recommendations
|Grade of Recommendation
||Body of evidence can be trusted to guide practice
||Body of evidence can be trusted to guide practice in most situations
||Body of evidence provides some support for recommendation(s) but care should be taken in its application
||Body of evidence is weak and recommendation must be applied with caution
Hierarchy of Evidence
||A systematic review of level II studies
||Randomized controlled trial (RCT) (good quality)
||A pseudo-RCT (i.e., alternate allocation or some other method) or RCT (poor quality)
||A comparative study with concurrent controls:
- Non-randomized, experimental trial
- Cohort study, case-control study, Interrupted time series with a control group (good quality)
||A comparative study without concurrent controls:
- Historical control study
- Cohort study, case-control study, interrupted time series with a control group (poor quality)
- Interrupted time series without a parallel control group
- Two or more single arm studies
||Case series with either post-test or pre-test/post-test outcomes