LINEE GUIDA ASCO/CAP SULLA DIAGNOSTICA DI HER2

Transcription

1 LINEE GUIDA ASCO/CAP SULLA DIAGNOSTICA DI HER2 Anna Sapino Dip. di Scienze Mediche-Università di Torino Dip. Di Medicina di Laboratorio- Città della Salute e della Scienza di Torino

2 JCO (2013):

3 ASCO- CAP 2013 (Arch Pathol Lab Med. 2014;138: )

4 ASCO- CAP 2013 PATIENT AND CLINICIAN COMMUNICATION Patients (and family members or caregivers) should be educated about the results of pathology tests and how they are used to develop a treatment plan tailored to the biology of their cancers.

5 Key Points for Clinicians to Discuss With Patients Regarding HER2 Status Explain the importance of determining the biologic characteristics of breast cancer Explain the importance of HER2 testing Explain the type of tissue used for HER2 testing Explain the types of tests used to determine HER2 status Explain the interpretation of the HER2 test results Explain the importance of retesting HER2 status in new, metastatic tumors Explain that HER2 testing guidelines exist

6 Key Points for Clinicians to Discuss With Patients Regarding HER2 Status Explain that HER2 testing guidelines exist: Patients should be assured that HER2 testing guidelines were followed. Refer patients to the ASCO/CAP guideline update at and/or and to for additional patient-focused information.

7 SPECIMEN TO BE TESTED All primary breast cancer specimens and metastases should have at least one HER2 test performed All newly diagnosed patients with breast cancer must have a HER2 test performed. Patients who then develop metastatic disease must have a HER2 test performed in a metastatic site, if tissue sample is available.

8 ASCO- CAP 2013 specimens: surgical specimen metastases

9 ASCO- CAP 2013 specimens: surgical specimen metastases core biopsy

10 2013 Data Supplement 6: Preanalytic Issues Specimen selection: comparable results of ER, PgR and HER2 analysis on core needle biopsies and the subsequent excision sample from the same patient. core needle samples are usually placed directly into fixative within minutes and the formalin will infiltrate more quickly, resulting in more uniform and consistent tissue fixation.

11 The IF rules for pathologists RETEST IF the CORE NEEDLE biopsy specimen is NEGATIVE, 1. Tumor is grade 3 2. Amount of invasive tumor in the core biopsy is small 3. Resection specimen contains high-grade carcinoma that is morphologically distinct from that in the core 4. Core biopsy result is equivocal for HER2 after testing by both ISH and IHC 5. There is doubt about the specimen handling of the core biopsy (long ischemic time, short time in fixative, different fixative) or the test is suspected by the pathologist to be negative on the basis of testing error Arch Pathol Lab Med Vol 138, February 2014

12 The IF rules for pathologists RETEST if the following histopathologic findings occur and the INITIAL HER2 TEST was POSITIVE: Histologic grade 1 carcinoma of the following types: 1. Infiltrating ductal or lobular carcinoma, ER and PgR positive 2. Tubular (at least 90% pure) 3. Mucinous (at least 90% pure) 4. Cribriform (at least 90% pure) 5. Adenoid cystic carcinoma (90% pure) and often triple negative Do not retest if the initial HER2 test was negative

13 The IF rules for oncologist Oncologists should recommend HER2-targeted therapy if HER2 test result is Positive if there is no apparent histopathologic discordance with HER2 testing if clinically appropriate

14 Type of lesion: METASTASIS This should be especially considered for a patient who previously tested HER2 negative in a primary tumour and presents with disease recurrence with clinical behaviour suggestive of HER2-positive or triple-negative disease.

15 PATIENT AND CLINICIAN COMMUNICATION Explain the importance of retesting HER2 status in new, metastatic tumors. Patients should understand that HER2 status may occasionally be different (discordant) when comparing a previous primary tumor and a site of recurrence or in the setting of multiple simultaneous metastatic sites. In some cases, it is not possible to fully differentiate between a true biologic change, tumor heterogeneity, or variability in the performance of the assay.

16 Which test? IHC and FISH are equally considered as first test

17 Immunohistochemistry

18 Time of fixation

19 4B5, Herceptest, CB11

20 The Update Committee was sensitive to the concerns that surfaced after the publication of the 2007 guideline about the very small number of patients [0.78% (if first tested by IHC) or 1.1% (if first tested by FISH)] potentially affected by the recommendation to consider as HER2 positive only those tumors with more than 30% of cells (or >10% to <30% if HER2 amplified by FISH) with diffuse and intense circumferential staining. Therefore, the Update Committee decided to revert to the previously used IHC criterion of >10% cells staining for HER2, which had been used as an entry criterion for eligibility for the first generation of prospective randomized trials of adjuvant trastuzumab.

21 4B5, Herceptest, CB11

22 Testing criteria define HER2- positive status when on observing within an area of tumor that amounts to >10% of contiguous and homogeneous tumor cells there is evidence of protein overexpression (IHC)

23 4B5, Herceptest, CB11

24 ASCO-CAP B5, Herceptest, CB11

25 4B5, Herceptest, CB11

26 2D) Consideration for Mandatory Retesting of All HER2-Negative Tests With proficiency testing and accreditation systems, the Update Committee concludes that the true frequency of a false-negative IHC test in a population-based study may be well below the intrinsic analytic variability of existing HER2 assays in clinical use, and did not support a recommendation for reflex testing of all patients with an IHC 1+ result as the initial HER2 testing.

27 ASCO-CAP 2013

28 Fluorescent ISH Chromogenic ISH

29 Fluorescent ISH Chromogenic ISH

30 Fluorescent ISH Chromogenic ISH

31 Data Supplement 2E: 2) HER2/CEP17 ratio 2.0 (average HER2 copy number < 4.0 signals/cell and average CEP17 < 2.0 signals/cell): (reference HERA trial JCO 27:2962-9, 2009) These cases are rare and could represent chromosome 17 monosomy. The Update Committee agreed that test results for cases with HER2 copy number < 4 and ratio 2.0 should be primarily reported as HER2-positive and this recommendation was made easier in view of the favorable safety profile of trastuzumab. At the same time, several members of the Update Committee expressed concern about describing an invasive breast cancer as HER2-positive on the basis of a single HER2 test showing a HER2/CEP17 ratio 2.0 and an average HER2 copy number < 4.0 signals/cell and recommended further testing of cases of this type. 31

32 ASCO-CAP 2013 DRAWBACKS April 28, 2014 We would like to bring two specific issues to the attention of committee members. First, the classification of cases with a HER2:CEP17 ratio >2 and average HER2 gene copies <4 as amplification does not make biologic sense. Rohit Bhargava and David J. Dabbs Magee-Womens Hospital of the University of Pittsburgh Medical Center, Pittsburgh, PA Given that amplification literally means an increase in the number of gene copies, how can one accept the case to be amplified when HER2 copies are not increased beyond what is normally 32

33 ASCO-CAP 2013 DRAWBACKS April 28, 2014 The authors Data Supplement 2E, which is supposed to provide clarification on this issue, clearly mentions that some committee members were against this stratification. The example of 48 patients from the Herceptin Adjuvant (HERA) trial with a ratio >2 and HER2 copies <4 is insufficient to classify these cases as amplified. Rohit Bhargava and David J. Dabbs Magee-Womens Hospital of the University of Pittsburgh Medical Center, Pittsburgh, PA 33

34 April 28, 2014 Data Supplement 2E mentions the favorable outcome of 453 patients in the HERA trial with ratios >2 but <4 in response to trastuzumab-containing therapy, which likely included these 48 patients, but does not specifically mention the separate outcome data on these 48 patients. Rohit Bhargava and David J. Dabbs Magee-Womens Hospital of the University of Pittsburgh Medical Center, Pittsburgh, PA 34

35 3.34% Fluorescent ISH Chromogenic ISH

36 2B) Polysomy Polysomy appears to be more common than monosomy, but arraybased comparative genomic hybridization (acgh) studies recently showed that true polysomy (duplication of the entire chromosome) is actually rare. However, loss or gain of the pericentromeric region of chromosome 17 is more commonly observed and can result in alterations in the HER2/CEP17 ratio and false-positive or falsenegative results. This update has been modified to avoid such false results.

37 Fluorescent ISH Chromogenic ISH

38 If the HER2 result is ultimately deemed to be equivocal, even after reflex testing with an alternative assay (ie, if neither test is unequivocally positive) the oncologist may consider HER2-target therapy. The oncologist should also consider the feasibility of testing another tumour specimen to attempt to definitely establish the tumour HER2 status and guide therapeutic decisions. A clinical decision to ultimately consider HER2- target therapy in such cases should be individualized on the basis of patient status (Comorbidities, prognosis and so on) and patient preferences after discussing available clinical evidence

39 Reflex test: equivocal The pathologist may pursue additional HER2 testing without conferring with the oncologist. This should be accomplished using: (1) the alternative test (IHC or ISH) on the same specimen, (2) either test on another block (same specimen), or (3) either test on another specimen (eg, core biopsy, surgical resection lymph node, and/or metastatic site). Because the decision to recommend HER2-targeted therapy requires a HER2- positive test result, additional HER2 testing should be attempted in equivocal specimens to attempt to obtain a positive or negative HER2 test result and most accurately determine the HER2 status of the tumor specimen.

40 ASCO- CAP 2013 Reflex test: equivocal If a reflex test (same specimen/same tissue) ordered after an initial equivocal HER2 test result does not render a positive or negative HER2 test result, the pathologist should 1. review histopathologic features 2. confer if possible with the oncologist regarding additional HER2 testing, and 3. document it in the pathology report. determine the HER2 status of the tumor specimen.

41 Fluorescent ISH Chromogenic ISH

42 Sapino A. The Oncologist 2014 in press

43 Sapino A. The Oncologist 2014 in press

44 Counting can be done by a trained technologist, but pathologist MUST confirm that result (count) is correct and that invasive tumor was counted. Pathologist MUST survey entire tumor before counting to define whether more than one population of cells is present and the percentage of the tumor that this population represents.

45 Quality control Laboratories are responsible for ensuring the reliability and accuracy of their testing results, by compliance with accreditation and proficiency testing requirements for HER2 testing assays. Specific concordance requirements are not required (Data Supplement 11).