Quantitative Image Analysis of HER2 Immunohistochemistry Compared with Manual Pathologist Analysis i

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Quantitative Image Analysis of HER2
Immunohistochemistry Compared with Manual
Pathologist Analysis in Breast CancerA Pilot
Study

• Keith J.Kaplan, MD
• Geoffrey L. Turner, MD PhD
• Grace E. Kronauer
• Northwestern University Feinberg School of
  Medicine
• Johns Hopkins University

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Background HER2

• Human epidermal growth factor receptor 2 gene
  ERBB2 (commonly referred to as HER2) is amplified
  in approximately 18 to 20 of breast cancers.
• HER2 overexpression is associated with clinical
  outcomes in patients with breast cancer.
• HER2 status is also predictive for several
  systemic therapies.

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Background

• Several studies have now shown that agents that
  target HER2 are remarkably effective in both the
  metastatic and adjuvant settings. Trastuzumab
  (Herceptin Genentech, South San Francisco, CA),
  a humanized monoclonal antibody, improves
  response rates, time to progression, and even
  survival when used alone or added to
  chemotherapy in metastatic breast cancer.
• Active as a single agent.
• Approve for the treatment of metastatic disease.

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Background

• HER2 testing should be routinely performed in
  patients with a new diagnosis of invasive breast
  cancer. However, the best method to assess HER2
  status, in regards both to the type of assay used
  and the optimal method to perform each assay,
  remains controversial.
• IHC with reflex of 2 to FISH
• Overexpression by IHC (3) or amplification by
  FISH considered positive result

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Background

• Several assays have been used for HER2
  determination in tissue. US Food and Drug
  Administration regulations also allow pathology
  laboratories to develop and implement so called
  home brew assays using US Food and Drug
  Administrationapproved analyte specific
  reagents.
• While some assays have been carefully validated,
  others, especially home brew assays, have not.
  Prospective substudies from two of the adjuvant
  randomized trials of trastuzumab versus nil have
  demonstrated that approximately 20 of HER2
  assays performed in the field (at the primary
  treatment site's pathology department) were
  incorrect when the same specimen was re-evaluated.

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Background

• Such a disorganized practice and high rate of
  inaccuracy, for such an important test that
  dictates a critically effective yet potentially
  life-threatening and expensive treatment, is not
  acceptable.   
• Trastuzumab therapy is not without its drawbacks.
  
• Therapy recommended for 12 months
• The drug cost of 52 weeks of trastuzumab in the
  community setting in the United States is
  approximately 100,000 based on average sales
  price (www.accc-cancer.org).

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Background

• Associated with a small risk of serious cardiac
  toxicity.
• Approximately 5 to 15 of patients develop
  cardiac dysfunction,
• Approximately 1 to 4 develop significant
  cardiac events (including symptomatic congestive
  heart failure) while taking trastuzumab.
• Taken together, the significant benefits coupled
  with the high cost and potential cardiotoxicity
  of trastuzumab demand accurate HER2 testing.

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Archives of Pathology and Laboratory Medicine
Vol. 131, No. 1, pp. 1843.
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• Image analysis can be an effective tool for
  achieving consistent interpretation. However, a
  pathologist must confirm the image analysis
  result. Image analysis equipment, just as other
  laboratory equipment, must be calibrated and
  subjected to regular maintenance and internal
  quality control evaluation. Image analysis
  procedures must be validated before
  implementation. One issue identified during the
  panel discussion was lack of calibration of the
  optical microscopes used by pathologists,
  something which certainly contributes to
  interpretive variation. If pathologists use
  several different microscopes to read assays, a
  system of calibration of these instruments should
  be implemented to ensure consistent
  interpretation.

Archives of Pathology and Laboratory Medicine
Vol. 131, No. 1, pp. 1843.
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Inconsistency of HER2 Test Raises Questions
J Natl Cancer Inst 200799(14)1064-1065.
The tests that determine who gets the powerful
breast cancer drug trastuzumab (Herceptin) may
not be as reliable as previously thought,
researchers reported at the annual meeting of the
American Society of Clinical Oncology. That means
some women who should be getting trastuzumab
treatment are not, while other women who will not
benefit are unnecessarily exposed to a drug that
can cause heart problems.
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Study Design

• Retrospectively reviewed 81 (81/122) breast
  cancers newly diagnosed within 2006 and tested
  for HER2 by IHC with reflex FISH testing in
  equivocal (2) cases (majority)
• LIS searched for FISH and HER2 in 2006
• Whole slide scanned using ScanScope and analyzed
  using membrane stain algorithm provided
• Algorithms not calibrated or standardized to
  our laboratory.
• Slides not re-reviewed or IHCs re-scored
• Non-sequential cases from 10 pathologists
• Home-brewed assay

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MA 1 FISH non-amplified IA 0
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MA 2 FISH non-amplified IA 1
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MA 2 FISH non-amplified IA 1
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MA 2 FISH non-amplified IA 1
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MA 3 FISH amplified IA 3
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Results

• IA more accurate than MA 68 (55/81)
• IA 1 compared with MA 2 IHC
• FISH non-amplified in all cases
• MA more accurate than IA 15 (12/81)
• 8/12 overscored 3 IHC (1 IHC MA)
• 8/8 FISH non-amplified
• 4/12 underscored 1 IHC (3 IHC MA)
• 3/4 FISH amplified
• IA equivalent to MA 17 (14/81)
• 1 to 3 with majority (8/14) as 2 IHC

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Results

• Scan time on order of a few minutes
• Processing time on order of 15 minutes for whole
  slide
• 2 slides unable to be scanned
• Extra resources needed to incorporate into
  workflow
• Retrieval of material, scanning, processing,
  analyzing and reporting

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Caveats

• Cases signed out prior to guidelines in 2007
• Home-brewed assay used for IHC
• Using FISH as gold standard rather than outcome
• Low threshold for calling indeterminate

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Conclusions

• IA appears to be more accurate than MA in HER2
  IHC, particularly for 2 cases (FISH
  non-amplified)
• Algorithms appeared to overscore or underscore a
  minority of cases, particularly 1 IHC cases
  (FISH non-amplified)
• Pilot study suggests a role for IA in 2 cases to
  avoid unnecessary FISH testing in overscored
  cases
• Cost and time required for WSI analysis may still
  be prohibitive for routine clinical use without
  added resources in the laboratory for IA.

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Office
Molecular
IA Workstation
Order HER2
Perform IA
Perform FISH?
Transcribe Results
Sign out case
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Conclusions

• CPT 88360 Morphometric analysis, tumor
  immunohistochemistry (eg, Her2/neu,
  estrogen/progesterone receptor), quantitative,
  semiquantitative, each antibody manual
• PCTC147.95
• CPT 88361 Morphometric analysis, tumor
  immunohistochemistry (eg, Her2/neu,
  estrogen/progesterone receptor), quantitative,
  semiquantitative, each antibody using computer
  assisted technology
• 88361 PCTC229.16 ?(TCPC)81.21
• HER2 FISH
• 88368 PCTC710.00

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Acknowledgments

• Aperio Technologies, Inc.
• Laura Nottoli, Craig Fenstermaker, Holger Lange
• Grace Kronauer
• Geoffrey Turner MD PhD
• Tracy Roberts

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Thank You
www.tissuepathology.com
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