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Contralateral Breast Cancer — SCE Medical Oncology MCQ

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EasyBreast CancerContralateral Breast CancerSCE Medical Oncology

A 58-year-old woman with ER+/HER2- breast cancer presents with a contralateral new breast primary 5 years after completing adjuvant treatment. What is the risk of contralateral breast cancer (CBC) after a first breast cancer?

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Correct answer: E — Approximately 0.5-1% per year (cumulative ~5-10% at 10 years); risk is higher with BRCA mutations, young age at first diagnosis, lobular histology and family history

Contralateral breast cancer occurs at a rate of approximately 0.5-1% per year (~5-10% cumulative at 10 years). Risk factors include: BRCA1/2 mutations (3-5% per year), young age (<40), lobular histology, family history and prior chest wall radiation. Adjuvant endocrine therapy reduces CBC risk by approximately 40-50%. Contralateral prophylactic mastectomy reduces CBC risk by >95% but has no proven OS benefit in non-BRCA carriers. Each new breast cancer should be independently biopsied and profiled.

Reference: NICE NG101; ESMO 2024 Early Breast Cancer; EBCTCG