• Interval breast cancer (a cancer found between screening rounds): An interval breast cancer is one diagnosed after a normal screening mammogram and before the next invitation.
• Homologous recombination deficiency (HRD) in breast cancer: Homologous recombination deficiency means a tumour cannot mend double-strand DNA breaks properly, most often because BRCA1 or BRCA2 is lost.
• Chemoprevention (tamoxifen, anastrozole, raloxifene) and ER-negative breast cancer: Tamoxifen and anastrozole taken for five years cut the number of new breast cancers in women at raised risk by a third to a half, and NICE offers them to women at high or moderate risk.
• Risk-reducing surgery for BRCA carriers (bilateral and contralateral mastectomy, salpingo-oophorectomy): Women who carry a BRCA1 or BRCA2 fault can choose to have both breasts removed before any cancer appears, which cuts breast cancer risk by about nine tenths, or to remove the other breast after a first cancer.
• Invasive disease-free survival (iDFS): Invasive disease-free survival is the yardstick of most trials that treat early breast cancer after surgery.
• Founder mutation (BRCA1 185delAG and 5382insC, BRCA2 6174delT): A founder mutation is a single inherited gene fault that many people in one population share because they descend from the same ancestor who carried it.
• Germline BRCA testing criteria for triple-negative breast cancer (UK): In the NHS a blood test for inherited BRCA1 and BRCA2 faults is offered to every woman under 50 with triple-negative breast cancer, whatever her family history, and hospital testing criteria now extend that to triple-negative disease under 60 and any breast cancer under 40.
• Basal-like breast cancer: Basal-like is a breast cancer subtype defined by the genes its cells switch on, which resemble the basal cells lining the milk ducts.
• Germline vs somatic mutations: Germline mutations are inherited and in every cell; somatic mutations arise in the tumour only.
• Mastectomy: Removing the whole breast, either for cancer or preventively in BRCA1/2 carriers, where bilateral risk-reducing mastectomy cuts breast cancer risk by 90% or more.

At diagnosis: Germline BRCA1 and BRCA2 testing for women under 50 with triple-negative disease including those with no family history (NICE NG101 1.3.6); UK mainstream criteria cover all triple-negative disease under 60; genetic counselling and cascade testing of relatives.

Biomarker results to ask for: Germline BRCA1, BRCA2 and PALB2 pathogenic variants (blood test), Tumour BRCA1 or BRCA2 mutation and HRD score (platinum and PARP inhibitor response), Age under 50 at diagnosis and family history (testing criteria).

Scans and tests linked to this cancer: Germline (hereditary) testing.

Bring copies of scan reports, pathology and blood results, and a list of every medicine and supplement.

• Early disease after chemotherapy: One year of adjuvant olaparib for germline BRCA-mutated HER2-negative high-risk early breast cancer (OlympiA; NICE TA886); the same neoadjuvant platinum, taxane and anthracycline regimen as other triple-negative disease (NG101 1.8). (Olaparib, OlympiA, PARP inhibitors, Carboplatin)
• Surgery and the other breast: Contralateral risk-reducing mastectomy lowers contralateral cancer incidence and all-cause mortality in carriers with breast cancer (meta-analysis); the decision weighs the prognosis of the first cancer and personal preference (POSH authors; NICE CG164 counselling steps). (Mastectomy, Risk-reducing surgery for BRCA carriers (bilateral and contralateral mastectomy, salpingo-oophorectomy))
• Metastatic disease: Olaparib or talazoparib (OlympiAD, EMBRACA); platinum chemotherapy; PD-L1 and TROP2 ADC options as for other triple-negative disease. (Olaparib, Talazoparib, OlympiAD, EMBRACA, Platinum agents)

From the standard of care recorded for this cancer; which apply depends on your stage and biomarkers. Ask which the team recommends and why.