Guideline Recommendations for HER2 Testing in Breast Cancer ASCO/College of American Pathologists Practice Guideline Rec

1. Guideline Recommendations for HER2 Testing in Breast Cancer ASCO/College of American Pathologists Practice Guideline Recommendations

2. Introduction • ASCO and the College of American Pathologists (CAP) convened an Expert Panel to develop a guideline to improve the accuracy of HER2 testing in invasive breast cancer and its utility as a predictive marker. • The guideline was reviewed by experts in clinical medicine and research and approved by the Board of Directors at both ASCO and CAP. • The ASCO/CAP Expert Panel included medical, academic and community experts as well as ex-officio representation from leading federal agencies including international representation from medical organizations.

3. Introduction (cont’d) • The ASCO/CAP Expert Panel composition: • Medical Oncology • Pathology • Epidemiology • Statistics • Health Services Research • Academic and Community Practitioners • Patient Representative • Federal Drug Administration (FDA) Representative* • Centers for Medicare & Medicaid Services (CMS) Representative* • National Cancer Institute (NCI) Representative • National Academy of Clinical Biochemistry Representative * Denotes Ex-Officio Status

4. Guideline Methodology: Systematic Review The Panel conducted a systematic review of the literature from January 1987 through February 2006: • MEDLINE • PreMEDLINE • Cochrane Collaboration Library • ASCO and CAP abstracts from 2000-2005 • Abstracts from the San Antonio Breast Cancer Symposium (2003-2005)

5. Guideline Methodology: Panel Members

6. Guideline Methodology: Panel Members (cont’d)

7. Background • HER2 is the common name for the human epidermal growth factor receptor 2 gene ERBB2. Additional aliases include • NEU • NGL • TKR1 • c-erb B2 • HER-2/neu Ligand binding domain Transmembrane Tyrosine kinase domain HER1 HER2 HER3 HER4 Herbst. Int J Radiat Oncol Biol Phys. 2004;59(suppl):21; Roskoski. Biochem Biophys Res Commun. 2004;319:1; Rowinsky. Annu Rev Med. 2004;55:433.

8. Background (cont’d) • HER2 amplification is the primary mechanism for overexpression • HER2 is amplified in 18-20% of breast cancers • HER2 overexpression is associated with certain clinical outcomes: • Higher risk of recurrence and mortality • Relative resistance to endocrine therapy • Apparent lesser benefit from certain chemotherapeutic regimens (e.g., non-anthracycline, non-taxane-containing agents)

9. Background (cont’d) • Agents that target the HER2 pathway have been developed for use in the metastatic and adjuvant settings • Trastuzumab (anti-HER2 therapy) was FDA-approved in 1998 for treatment of metastatic disease • Adjuvant trastuzumab reduces the risk of recurrence and mortality by ½ and 1/3 , respectively, in patients with early stage, high-risk breast cancers that overexpress HER2 • Costs for one year of trastuzumab range from $70,000-$110,000 • Trastuzumab correlates with asymptomatic cardiac dysfunction (5-15% of patients) and symptomatic congestive heart failure (2-4% of patients)

10. Background (cont’d) • Studies have shown that as many as 20% of HER2 assays performed in the field may be inaccurate • HER2 testing assays*: • Immunohistochemistry (IHC) • Fluorescence in situ hybridization (FISH) • Bright field in situ hybridization • Note: Home brew assays refer to any assay developed internally by an individual lab that may or not have been validated. Various FDA-Approved Assays

11. Background (cont’d) • The ASCO/CAP Expert Panel: • Recommends routine testing of HER2 in patients with invasive breast cancer • Addresses quality assurance measures and recommends specific methodology to improve HER2 testing accuracy

12. Background (cont’d): Statistical Considerations • Accuracy • How close the measured values are to a “true” value • Implicit that a suitable “gold standard” exists • With binary measurements (e.g., positive vs. negative): • Sensitivity: % of positive test results when evaluating true positives • Specificity: % of negative test results when evaluating true negatives • Accuracy: % concordance between evaluated assay and gold standard • Combines sensitivity and specificity into a single measure of the percentage of cases (positive and negative) for which the assay result agrees with the true status For a fuller discussion of statistical considerations, see Appendix G at www.asco.org/guidelines/her2

13. Guideline Questions • What is the optimal testing algorithm for the assessment of HER2 status? • What strategies can help ensure optimal performance, interpretation, and reporting of established assays?

14. Optimal Testing Algorithm for the Assessment of HER2 Status • HER2 testing results are categorized as positive, negative, or equivocal (new category) • Testing results definitions depend on laboratory documentation of the following items: • Proof of initial testing validation in which positive and negative HER2 categories are 95% concordant with alternative validated method or same validated method for HER2 (see Appendix F of the guideline on statistical requirements for assay validation, available at http://www.asco.org/guidelines/her2) • Ongoing internal QA procedures • Participation in ongoing external proficiency testing • Current accreditation by CAP or another valid accrediting agency

15. Optimal Testing Algorithm (cont’d)

16. Optimal Testing Algorithm (cont’d) • HER2 analysis must be preformed on the invasive component of breast cancer since HER2 overexpression and/or amplification is frequently increased in situ • Equivocal results require additional action: * Confirmatory IHC is recommended if FISH remains equivocal so that HER2 protein expression is known for the sample with true equivocal gene amplification status

17. Optimal Testing Algorithm (cont’d): IHC Breast cancer specimen (invasive component) HER2 testing by validated IHC assay for HER2 protein expression Positive for HER2 protein expression IHC 3+ (defined as uniform intense membrane staining of >30% of invasive tumor cells) Negative for HER2 protein expression IHC 0 or 1+ Equivocal for HER2 protein expression IHC 2+ Test with validated assay for HER2 gene amplification Positive for HER2 gene amplification Negative for HER2 gene amplification Equivocal HER2 gene amplification (Patients with HER2/CEP17 ratio ≥2.0 were eligible for the adjuvant trastuzumab trials)

18. Optimal Testing Algorithm (cont’d): FISH Breast cancer specimen (invasive component) HER2 testing by validated FISH assay for HER2 gene amplification Positive for HER2 gene amplification (FISH ratio >2.2 or HER2 gene copy >6.0) Equivocal for HER2 gene amplification (FISH ratio 1.8-2.2 or HER2 gene copy 4.0-6.0) Negative for HER2 gene amplification (FISH ratio <1.8 or HER2 gene copy <4.0) Count additional cells for FISH or retest, or test with HER2 IHC Equivocal HER2 gene amplification result (Patients with HER2/CEP17 ratio ≥2.0 were eligible for the adjuvant trastuzumab trials)

19. Optimal Performance, Interpretation & Reporting • Laboratories that test for HER2 are required to participate in proficiency testing • HER2 status should be used for patient management only if the testing laboratory is CAP-accredited or has met accreditation requirements outlined in the ASCO/CAP guideline • Oncologists are encouraged to verify the laboratory accreditation status as well as confirm standardized reporting elements for IHC and/or FISH when reviewing HER2 test assessments

20. Standardized Reporting Elements for IHC • Patient identification information • Physician identification • Date of service • Specimen identification (case and block number) • Specimen site and type • Specimen fixative type • Time to fixation (if available) • Duration of fixation (if available) • Antibody clone/vendor • Method used (specifics of test/vendor and if FDA-approved) • Image analysis method (if used) • Controls (high protein expression, low-level protein expression, negative protein expression, internal) • Adequacy of sample for evaluation • Results • Percentage of invasive tumor cells exhibiting complete membrane staining • Uniformity of staining: present/absent • Homogeneous, dark circumferential pattern: present/absent • Interpretation

21. Standardized Reporting Elements for FISH • Patient identification information • Physician identification • Date of service • Specimen identification (case and block number) • Specimen site and type • Specimen fixative type • Time to fixation (if available) • Duration of fixation (if available) • Probe(s) identification • Method used (specifics of test/vendor and if FDA-approved) • Image analysis method (if used) • Controls (amplified, equivocal, and non-amplified, internal) • Adequacy of sample for evaluation (adequate number if invasive tumor cells present) • Results • Number of invasive tumor cells counted • Number of observers • Average number of HER2 signals/nucleus or tile • Average number of CEP 17 chromosome probes/nucleus or tile • Ratio of average HER2 signals/CEP 17 probe signals • Interpretation

22. Optimal Performance, Interpretation & Reporting (cont’d) • The ASCO/CAP Expert Panel strongly recommends: • Validation of laboratory assay or modifications • Use of standardized operating procedures, and • Compliance with new testing criteria to be monitored with the use of stringent laboratory accreditation standards, proficiency testing, and competency assessment.

23. Optimal Performance, Interpretation & Reporting (cont’d) • For specific recommendations and protocols review the full-text guideline at: • ASCO http://www.asco.org/guidelines/her2 • CAP http://www.cap.org • Also review the following guideline appendices in the manuscript: • Appendix C: Evidence of HER2 Status and Trastuzumab Benefit • Appendix D: Evidence of HER2 Testing Variation • Appendix E: Tissue Handling Requirements and Control Materials • Appendix F: Statistical Requirements for Assay Validation • Appendix G: Interpretation Criteria and Test Reporting of HER2 Test • Appendix H: Regulatory Requirements for Laboratories • Appendix I: International External Quality Assessment Initiatives

24. Additional ASCO/CAP Resources • The full-text guideline as well as the following tools and resources are available at: http://www.asco.org/guidelines/her2 • Summary Slide Set • Guideline Summary • HER2 Patient Guide (at www.cancer.net) • HER2 Reporting Elements Index

25. ASCO Guidelines