The fraction of malignant cells in tumor tissue submitted for tests of genetic alterations is a critical variable in testing accuracy. That fraction is currently determined by pathologist visual ...estimation of the percentage of malignant cells. Inaccuracy could lead to a false-negative test result.
To describe a prospective, multi-institutional study to determine pathologist estimation accuracy.
Ten ×20 magnification images of hematoxylin-eosin-stained colon tissue specimens were sent as an educational component of the College of American Pathologists KRAS-B 2011 Survey. Data from 194 labs were analyzed and compared to a criterion standard with comprehensive manual nuclear counts.
Survey responses indicated low interlaboratory precision of pathologist estimation, but mean estimates were fairly accurate. A total of 5 of the 10 cases assessed showed more than 10% of respondents overestimating in a manner that could lead to false-negative test results.
The significance of estimation errors resulting in molecular testing failures with implications for patient care is unknown, but the current study suggests false-negative test results may occur.
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Next-generation sequencing-based assays are being increasingly used in the clinical setting for the detection of somatic variants in solid tumors, but limited data are available regarding the ...interlaboratory performance of these assays.
To examine proficiency testing data from the initial College of American Pathologists (CAP) Next-Generation Sequencing Solid Tumor survey to report on laboratory performance.
CAP proficiency testing results from 111 laboratories were analyzed for accuracy and associated assay performance characteristics.
The overall accuracy observed for all variants was 98.3%. Rare false-negative results could not be attributed to sequencing platform, selection method, or other assay characteristics. The median and average of the variant allele fractions reported by the laboratories were within 10% of those orthogonally determined by digital polymerase chain reaction for each variant. The median coverage reported at the variant sites ranged from 1922 to 3297.
Laboratories demonstrated an overall accuracy of greater than 98% with high specificity when examining 10 clinically relevant somatic single-nucleotide variants with a variant allele fraction of 15% or greater. These initial data suggest excellent performance, but further ongoing studies are needed to evaluate the performance of lower variant allele fractions and additional variant types.
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Detection of high-risk human papillomavirus (HR-HPV) in squamous cell carcinoma is important for classification and prognostication. In situ hybridization (ISH) is a commonly used HR-HPV-specific ...test that targets viral RNA or DNA. The College of American Pathologists (CAP) provides proficiency testing for laboratories performing HR-HPV ISH.
To compare the analytical performance of RNA- and DNA-based ISH methods on CAP HR-HPV proficiency tests.
Data from the 2016-2018 CAP HPV ISH proficiency testing surveys were reviewed. These surveys consist of well-characterized samples with known status for HR-HPV, including 1 to 2 copies, 50 to 100 copies, 300 to 500 copies, and no copies of HR-HPV per cell.
Ninety-five participants submitted 1268 survey results from 20 cores. Overall, RNA ISH had a significantly higher percentage of correct responses than DNA ISH: 97.4% (450 of 462) versus 80.6% (650 of 806) (
< .001). This disparity appears to be the consequence of a superior sensitivity of RNA ISH compared to DNA ISH for samples with 1 to 2 and with 50 to 100 copies of HR-HPV per cell: 95.2% (120 of 126) versus 53.8% (129 of 240),
< .001, respectively, and 100% (89 of 89) versus 76.3% (119 of 156),
< .001, respectively.
An assessment of CAP HR-HPV proficiency test performance indicates that RNA ISH shows significantly higher accuracy than DNA ISH owing to higher analytical sensitivity of RNA ISH in tumors with low (1-2 copies per cell) to intermediate (50-100 copies per cell) HR-HPV viral copy numbers. These data support the use of RNA over DNA ISH in clinical laboratories that perform HR-HPV testing as part of their testing algorithms.
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Fluorescence in situ hybridization (FISH) and brightfield in situ hybridization (ISH) are 2 clinically approved laboratory methods for detecting ERBB2 (HER2) amplification in breast cancer.
To ...compare the performance of FISH and brightfield ISH on proficiency testing administered by the College of American Pathologists Laboratory Accreditation Program.
Retrospective review was performed on 70 tissue core samples in 7 separate proficiency testing surveys conducted between 2009 and 2013.
The samples included 13 consensus-amplified tissue cores, 53 consensus-nonamplified cores, and 4 cores that did not reach consensus for FISH and/or brightfield ISH. There were 2552 individual responses for FISH and 1871 individual responses for brightfield ISH. Consensus response rates were comparable for FISH (2474 of 2524; 98.0%) and brightfield ISH (2135 of 2189; 97.5%). The FISH analysis yielded an average HER2 copy number per cell that was significantly higher (by 2.86; P = .02) compared with brightfield ISH for amplified cores. For nonamplified cores, FISH yielded slightly, but not significantly, higher (by 0.17; P = .10) HER2 copy numbers per cell. There was no significant difference in the average HER2 to control ratio for either consensus-amplified or consensus-nonamplified cores. Participants reported "unable to analyze" more frequently for brightfield ISH (244 of 2453; 9.9%) than they did for FISH (160 of 2684; 6.0%).
Our study indicates a high concordance rate in proficiency testing surveys, with some significant differences noted in the technical performance of these assays. In borderline cases, updated American Society of Clinical Oncology/College of American Pathologists cutoff thresholds that place greater emphasis on HER2 copy number per cell could accentuate those differences between FISH and brightfield ISH.
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Purpose Clinical use of analytical tests to assess genomic variants in circulating tumor DNA (ctDNA) is increasing. This joint review from ASCO and the College of American Pathologists summarizes ...current information about clinical ctDNA assays and provides a framework for future research. Methods An Expert Panel conducted a literature review on the use of ctDNA assays for solid tumors, including pre-analytical variables, analytical validity, interpretation and reporting, and clinical validity and utility. Results The literature search identified 1,338 references. Of those, 390, plus 31 references supplied by the Expert Panel, were selected for full-text review. There were 77 articles selected for inclusion. Conclusion The evidence indicates that testing for ctDNA is optimally performed on plasma collected in cell stabilization or EDTA tubes, with EDTA tubes processed within 6 hours of collection. Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity and clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, re-evaluation of the literature will shortly be required, along with the development of tools and guidance for clinical practice.
- Recurrent epidermal growth factor receptor ( EGFR) mutations are seen in a subset of pulmonary adenocarcinomas. These mutations are targeted by EGFR inhibitors and are a biomarker for response to ...EGFR inhibitor therapies. Initial data have indicated an increased frequency of activating EGFR mutations in nonsmoking Asian females. However, there are very few studies of global scope that address the question of mutation distribution across the population of lung cancer.
- To determine the frequency of EGFR mutations in exons 18 through 21 detected in clinical laboratories participating in the College of American Pathologists proficiency testing program for EGFR in calendar year 2013.
- We reviewed the surveys from 170 clinical laboratories from 20 countries that participated in the College of American Pathologists EGFR proficiency testing program. The proficiency testing includes questions regarding the total numbers of tests performed at each common mutation site, including both activating and resistance mutations, and their frequency. Countries were grouped into regional groups in order to assess frequency of mutation by type, and to indirectly assess ethnic differences in mutation frequencies.
- Among the treatment-sensitive activating mutations, the most common are exon 19 mutations (n = 10 802 of 136 533 cases; 7.9% of total cases tested) and the exon 21 L858R mutation (n = 10 351 of 136 533 cases; 7.6% of total cases tested) and the least common are exon 20 mutations (n = 466 of 136 533 cases; 0.3% of total cases tested). The T790M mutation in exon 20 is the more common resistance mutation (n = 1010 of 136 533 cases; 0.7% of all cases tested). The highest activating mutation frequency is seen in southern Asia (n = 4260 of 9337 cases; 46%) and the lowest activating mutation frequencies are in South and North America (n = 113 of 1439 cases and 7926 of 86 654 cases; 8% and 9%, respectively).
- Our data confirm that activating EGFR mutations are more common in southern Asia and that the distribution of activating EGFR mutations varies significantly across the regions. Similarly, the frequency and distribution of resistance mutations also show significant variation when comparing southern Asia with other regions.
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Clinical use of analytical tests to assess genomic variants in circulating tumor DNA (ctDNA) is increasing. This joint review from the American Society of Clinical Oncology and the College of ...American Pathologists summarizes current information about clinical ctDNA assays and provides a framework for future research.
An Expert Panel conducted a literature review on the use of ctDNA assays for solid tumors, including preanalytical variables, analytical validity, interpretation and reporting, and clinical validity and utility.
The literature search identified 1338 references. Of those, 390, plus 31 references supplied by the Expert Panel, were selected for full-text review. There were 77 articles selected for inclusion.
The evidence indicates that testing for ctDNA is optimally performed on plasma collected in cell stabilization or EDTA tubes, with EDTA tubes processed within 6 hours of collection. Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens, and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity or clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, reevaluation of the literature will shortly be required, along with the development of tools and guidance for clinical practice.
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Title 45, section 164.524 of the Code of Federal Regulations states that health care systems must provide patient health records upon that patient's request. For complex testing, such as ...next-generation sequencing (NGS), this raises questions related to what data should be released and the laboratory considerations regarding the release of this data.
To describe the laboratory implications of releasing different NGS data files and the limitations for the clinical use of different NGS data files.
The College of American Pathologists workgroup, composed of laboratorians with expertise regarding NGS testing, reviewed pertinent literature, including title 45, section 164.524, and the Health and Human Services "Guidance on Individuals' Right to Access Health Information."
From an accreditation standpoint, validation of NGS includes both the wet bench and data processing (bioinformatics) portions, and appropriately validated laboratory testing is required to ensure quality patient results. NGS testing generates intermediate data files that have not completed the fully validated process but are often kept by the laboratory. These files may be requested by patients, but most patients will not be aware of the test validation process and the limitations of data that have not gone through a fully validated process.
Laboratories should encourage patients to receive their health data and to help individuals understand the content, uses, and limitations of laboratory data they have requested or received. NGS data used in a nonvalidated manner should not be used for clinical purposes without confirmation by a clinically validated method.
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