| Guideline statement | LoE/GoR | Consensus |
|---|---|---|
| Genetic testing | ||
| In the ABC setting, results from genetic testing may have therapeutic implications and should therefore be considered as early as possible. | Expert opinion/B | 100% |
| Genes to be tested for depend on personal and family history; however, at present, only germline mutations in BRCA1/2 have proven clinical utility and therapeutic impact. | I/A | 100% |
| Testing for other additional moderate- to high-penetrance genes may be considered, if deemed appropriate by the geneticist/genetic counsellor. However, it must be clarified to the patient that at present, a mutation in another moderate- to high-penetrance gene has no direct clinical implications, for the patients themselves, in the setting of ABC. | Expert opinion/C | 100% |
| The therapeutic implications of somatic BRCA1/2 mutations in breast tumours need to be further explored within a research setting and should not be used for decision making in routine clinical practice. | n/a/E | 83% |
| BRCA-associated ABC | ||
| In patients with BRCA-associated advanced TNBC or endocrine-resistant ABC previously treated with an anthracycline with or without a taxane (in the adjuvant and/or metastatic setting), a platinum regimen is the preferred option, if not previously administered and no suitable clinical trial is available. All other treatment recommendations are similar to sporadic ABC. | II/A | 86% |
| A PARPi (olaparib or talazaparib) is a reasonable treatment option for patients with BRCA-associated advanced TNBC or luminal (after progression on ET) ABC, previously treated with an anthracycline with/without a taxane (in the adjuvant and/or metastatic setting), since its use is associated with a PFS benefit, improvement in QoL and a favourable toxicity profile. OS results are awaited. It is unknown how PARPis compare with platinum compounds in this setting and their efficacy in truly platinum-resistant tumours. | I/B | 80% |
In green, NEW ABC 4 statements.
ABC, advanced breast cancer; Consensus, percentage of panel members in agreement with the statement; ET, endocrine therapy; GoR, grade of recommendation; LoE, available level of evidence; OS, overall survival; PARPi, poly adenosine diphosphate ribose polymerase inhibitor; PFS, progression-free survival; QoL, quality of life; TNBC, triple-negative breast cancer.