|
Advertisement |
|
|
||
 |
|
|||||
|
|||||
|
 |
||||||
|
||||||
|
||||||
|
Originally published as JCO Early Release 10.1200/JCO.2009.24.0366 on September 8 2009 © 2009 American Society of Clinical Oncology.
Reply to G. Sauter et alIntermountain Healthcare, Salt Lake City, UT
The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD
University of Michigan Comprehensive Cancer Center, Ann Arbor, MI
Presbyterian Healthcare, Charlotte, NC In a recently published narrative review, Sauter et al1 raise several well-considered objections to a previously reported guideline document on HER2 testing developed by a panel jointly convened by the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP).2,3 Sauter and his coauthors, one of whom was a member of the ASCO-CAP panel, maintain that HER2 gene testing by fluorescent in situ hybridization (FISH) is more accurate and reproducible to qualify breast cancer patients for treatment with trastuzumab (and more recently, lapatinib). As representatives of the ASCO-CAP panel, we wish to provide a clarifying response to Sauter et al. We do not disagree that FISH testing may be more accurate than immunohistochemistry, especially if the former is performed in selected, highly qualified laboratories such as those directed by the authors. However, their assertion ignores the fundamental purpose of the guideline document, which was intended to create standardized performance criteria to improve the quality of all testing for HER2, regardless of the method.2 The ASCO-CAP panel was convened on the heels of several published reports that the performance of HER2 testing, performed by either method in the primary institution of diagnosis, was frequently inaccurate when repeated in centralized clinical laboratories.4,5 With the observation of the benefit of trastuzumab therapy in both metastatic and adjuvant settings, combined with its occasional life-threatening toxicity, universal inconvenience of administration, and high cost, the panel concluded that inaccurate HER2 testing is simply unacceptable.2,6–8 A comprehensive review of available data satisfied the panelists and the leaders of both organizations that there was not a gold-standard test method. Rather, the panel concluded that intra- and interlaboratory technical variation was a major obstacle to accurate HER2 testing, and recommended that all current laboratory methods (IHC or FISH) must be subject to more stringent standardized methods to protect patients and provide them with accurate test results. Guidelines are based on the principle that evidence-based and/or consensus-based clarity in medical diagnosis and treatment protocols and procedures will enhance the quality of medical care.9 Both ASCO and CAP subscribe to this principle, as do many other professional organizations.2,10–14 The recommendations from the ASCO-CAP HER2 panel encompass the major issues in testing that must be standardized if all testing for HER2 receptor protein or genes is to be improved. The guideline spells out definitions of positive, equivocal, and negative test results, standards for reporting those results, and methods by which laboratories can assure that their performance is accurate and reproducible over time. The standards adapted from the guideline and set forth by CAP apply to all laboratory testing for HER2, regardless of method. Pathologists are encouraged to properly examine, fix, process, interpret, and report testing. Standards for both internal and external quality assurance are defined so that laboratory performance can be established properly and maintained over time. Although we respect the concerns of Sauter et al, their review does not address this underlying principle; rather, it provides criticism of specific recommendations and statements in the guideline document. By focusing on current performance of IHC assays for HER2 and their deficiencies, Sauter et al merely reinforce the necessity of creating guidelines that solve these problems prospectively. Indeed, their well-annotated examples of IHC problems illustrate that guideline recommendations aimed at standardizing performance are important. Also, their own recent experience with the occurrence of false-negative HER2 FISH testing performed in a large, high-volume commercial reference laboratory as part of a randomized clinical trial of paclitaxel plus lapatinib or placebo attest to the need for high-quality testing, regardless of assay platform.15,16 We particularly wish to clarify a concern of Sauter et al regarding determination of samples tested by IHC that require reflexing to FISH testing. The guideline document clearly defines whether and why a specific laboratory is required to perform reflex FISH testing. These criteria, for each laboratory, are based on the guideline recommendation that any test performed without reflexing to FISH must be 95% concordant with FISH, defined on initial testing validation by the laboratory. Thus, if a laboratory does not achieve this concordance rate for its HER2 0, 1+, and 3+ samples, it must, in standard practice, also resort to reflex FISH testing for samples that score in these categories. The concordance study performed in each laboratory is done on local samples before the local reflex to FISH algorithm is defined. The local concordance study becomes part of the laboratory record for the HER2 testing procedure and is subject to review by inspectors to assure compliance with the guideline. Revalidation of this concordance is required on at least an annual basis. In this way, the guideline assures that all IHC laboratory assays are concordant with FISH testing 95% of the time unless FISH testing is also performed. Likewise, for laboratories that principally use FISH as a first test, reflex testing with IHC for equivocal patient cases is also recommended in the guidelines. Several testing issues (genomic heterogeneity and aneuploidy) encountered with FISH testing are the subject of additional guideline recommendations from CAP, requested to be promulgated by the original panel (Hammond et al, manuscript in preparation).17 Since publication of the ASCO-CAP HER2 document in 2007, laboratory compliance with the guideline-directed recommendations has increased substantially (M. Paton, personal communication, 2008).18 We believe this improved compliance is due to enhanced awareness of conditions that might significantly alter results, promoted by required proficiency testing challenges and laboratory inspections. ASCO and CAP have been so encouraged by the response to the ASCO-CAP guidelines for HER2 that they have embarked on another guideline to define standards for hormone receptor testing in breast cancer. In addition, CAP has recently cooperated in the development of preliminary standards for KRAS testing in metastatic colon cancer.19 The leadership of CAP is convinced that standardization of practice will improve pathology practice in regards to testing accuracy and will, therefore, ultimately lead to more efficient application of life-saving therapies. CAP has embarked on a new program to create and standardize pathology practice across the specialty, most often by collaborating with other professional organizations such as ASCO so that uniform standards can be promulgated. Individual laboratories will continue to provide innovation and excellence to be emulated, but it is only through the dissemination of standardized practice that the hope of improvement of laboratory testing for all patients can be realized. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST Although all authors completed the disclosure declaration, the following author(s) indicated a financial or other interest that is relevant to the subject matter under consideration in this article. Certain relationships marked with a "U" are those for which no compensation was received; those relationships marked with a "C" were compensated. For a detailed description of the disclosure categories, or for more information about ASCO's conflict of interest policy, please refer to the Author Disclosure Declaration and the Disclosures of Potential Conflicts of Interest section in Information for Contributors. Employment or Leadership Position: None Consultant or Advisory Role: None Stock Ownership: None Honoraria: None Research Funding: Antonio C. Wolff, Genentech; Daniel F. Hayes, Pfizer, Novartis, AstraZeneca, Veridex Expert Testimony: None Other Remuneration: None REFERENCES
1. Sauter G, Lee J, Bartlett JM, et al: Guidelines for human epidermal growth factor receptor 2 testing: Biologic and methodologic considerations. J Clin Oncol 27:1323–1333, 2009. 2. Wolff AC, Hammond ME, Schwartz JN, et al: American Society of Clinical Oncology/College of American Pathologists guideline recommendations for human epidermal growth factor receptor 2 testing in breast cancer. J Clin Oncol 25:118–145, 2007. 3. Wolff AC, Hammond EH, Schwartz JN, et al: In Reply. J Clin Oncol 25:4021–4023, 2007. 4. Perez EA, Suman VJ, Davidson NE, et al: HER2 testing by local, central, and reference laboratories in specimens from the North Central Cancer Treatment Group N9831 intergroup adjuvant trial. J Clin Oncol 24:3032–3038, 2006. 5. Paik S, Bryant J, Tan-Chiu E, et al: Real-world performance of HER2 testing: National Surgical Adjuvant Breast and Bowel Project experience. J Natl Cancer Inst 94:852–854, 2002. 6. Romond EH, Perez EA, Bryant J, et al: Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer. N Engl J Med 353:1673–1684, 2005. 7. Piccart-Gebhart MJ, Procter M, Leyland-Jones B, et al: Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer. N Engl J Med 353:1659–1672, 2005. 8. Slamon DJ, Leyland-Jones B, Shak S, et al: Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. N Engl J Med 344:783–792, 2001. 9. Lohr KN, Eleazer K, Mauskopf J: Health policy issues and applications for evidence-based medicine and clinical practice guidelines. Health Policy 46:1–19, 1998.[CrossRef][Medline] 10. O'Malley FP, Thomson T, Julian J, et al: HER2 testing in a population-based study of patients with metastatic breast cancer treated with trastuzumab. Arch Pathol Lab Med 132:61–65, 2008.[Medline] 11. Umemura S, Osamura RY, Akiyama F, et al: What causes discrepancies in HER2 testing for breast cancer? A Japanese ring study in conjunction with the global standard. Am J Clin Pathol 130:883–891, 2008. 12. Yaziji H, Taylor CR: Begin at the beginning, with the tissue! The key message underlying the ASCO/CAP task force guideline recommendations for HER2 testing. Appl Immunohistochem Mol Morphol 15:239–241, 2007.[CrossRef][Medline] 13. Dowsett M, Hanby AM, Laing R, et al: HER2 testing in the UK: Consensus from a national consultation. J Clin Pathol 60:685–689, 2007. 14. Carlson RW, Moench SJ, Hammond ME, et al: HER2 testing in breast cancer: NCCN Task Force report and recommendations. J Natl Compr Canc Netw 4:S1–S22, 2006 (suppl 3) quiz S23-S24. 15. Press MF, Finn RS, Cameron D, et al: HER-2 gene amplification, HER-2 and epidermal growth factor receptor mRNA and protein expression, and lapatinib efficacy in women with metastatic breast cancer. Clin Cancer Res 14:7861–7870, 2008. 16. Di Leo A, Gomez HL, Aziz Z, et al: Phase III, double-blind, randomized study comparing lapatinib plus paclitaxel with placebo plus paclitaxel as first-line treatment for metastatic breast cancer. J Clin Oncol 26:5544–5552, 2008. 17. Vance GH, Barry TS, Bloom KJ, et al: Genetic heterogeneity in HER2 testing in breast cancer: Panel summary and guidelines. Arch Pathol Lab Med 133:611–612, 2009.[Medline] 18. Wasielewski R, Hasselmann S, Ruschoff J, et al: Proficiency testing of immunohistochemical biomarker assays in breast cancer. Virchows Arch 453:537–543, 2008.[CrossRef][Medline] 19. Allegra CJ, Jessup JM, Somerfield MR, et al: American Society of Clinical Oncology provisional clinical opinion: Testing for KRAS gene mutations in patients with metastatic colorectal carcinoma to predict response to anti-epidermal growth factor receptor monoclonal antibody therapy. J Clin Oncol 27:2091–2096, 2009.
Related Article
This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||
|
|||||||||||
|
|
Copyright © 2009 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
|
