Scolyer RA, Atkinson V, Gyorki DE, Lambie D, O'Toole S, Saw RPM, Amanuel B, Angel CM, Button-Sloan AE, Carlino MS, Ch'ng S, Colebatch AJ, Daneshvar D, Pires da Silva I, Dawson T, Ferguson PM, Foster-Smith E, Fox SB, Gill AJ, Gupta R, Henderson MA, Hong AM, Howle JR, Jackett LA, James C, Lee CS, Lochhead A, Loh D, McArthur GA, McLean CA, Menzies AM, Nieweg OE, O'Brien BH, Pennington TE, Potter AJ, Prakash S, Rawson RV, Read RL, Rtshiladze MA, Shannon KF, Smithers BM, Spillane AJ, Stretch JR, Thompson JF, Tucker P, Varey AHR, Vilain RE, Wood BA, and Long GV
Targeted therapy (BRAF inhibitor plus MEK inhibitor) is now among the possible treatment options for patients with BRAF mutation-positive stage III or stage IV melanoma. This makes prompt BRAF mutation testing an important step in the management of patients diagnosed with stage III or IV melanoma; one that can help better ensure that the optimal choice of systemic treatment is initiated with minimal delay. This article offers guidance about when and how BRAF mutation testing should be conducted when patients are diagnosed with melanoma in Australia. Notably, it recommends that pathologists reflexively order BRAF mutation testing whenever a patient is found to have American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) stage III or IV melanoma (i.e., any metastatic spread beyond the primary tumour) and that patient's BRAF mutation status is hitherto unknown, even if BRAF mutation testing has not been specifically requested by the treating clinician (in Australia, Medicare-subsidised BRAF V600 mutation testing does not need to be requested by the treating clinician). When performed in centres with appropriate expertise and experience, immunohistochemistry (IHC) using the anti-BRAF V600E monoclonal antibody (VE1) can be a highly sensitive and specific means of detecting BRAF V600E mutations, and may be used as a rapid and relatively inexpensive initial screening test. However, VE1 immunostaining can be technically challenging and difficult to interpret, particularly in heavily pigmented tumours; melanomas with weak, moderate or focal BRAF V600E immunostaining should be regarded as equivocal. It must also be remembered that other activating BRAF V600 mutations (including BRAF V600K ), which account for ∼10-20% of BRAF V600 mutations, are not detected with currently available IHC antibodies. For these reasons, if available and practicable, we recommend that DNA-based BRAF mutation testing always be performed, regardless of whether IHC-based testing is also conducted. Advice about tissue/specimen selection for BRAF mutation testing of patients diagnosed with stage III or IV melanoma is also offered in this article; and potential pitfalls when interpreting BRAF mutation tests are highlighted., (Copyright © 2021 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)