When Chemotherapy Can Be Avoided: Genomic Testing in Early Breast Cancer

Definitive, curative treatment absolutely exists for early breast cancer: stage one and stage two patients see close to 100% results with protocols matched to the tumour's subtype, adjusted further for the patient's comorbidities and financial circumstances. For metastatic breast cancer, a cure isn't currently possible, but survival and quality of life have improved substantially compared with a few years ago. Breast cancer is the most common cancer among women, but most cancer deaths are actually from lung cancer, not breast cancer, which is part of why even stage four disease now sees meaningfully better survival than before. There is no single protocol; treatment has to be customised to the patient's age, subtype and disease status in each case.

In early breast cancer, biopsy is usually a guided procedure taken directly from the lesion itself, using a simple technique: fixation of the tissue followed by histopathology, then immunohistochemistry to determine oestrogen receptor, progesterone receptor and HER2 status. If HER2 comes back equivocal on immunohistochemistry, a FISH test confirms it. In metastatic disease involving organs such as the lung, bone or liver, the biopsy is taken from whichever site is most accessible and least risky for the patient, often the liver or the lung. In patients too unwell for any other biopsy, such as those presenting with severe anaemia, a bone marrow biopsy can confirm metastatic breast cancer directly, including its subtype through immunohistochemistry on that same sample, allowing treatment to proceed with good results.

The most common cause is advancing age; risk rises with it. Other contributing factors include early menarche, late menopause, never having children, having a first child after age 35, reduced breastfeeding, smoking, and alcohol consumption of any quantity. Genetic factors matter too: a first-degree relative with breast or ovarian cancer, or a positive result for high-penetrance genes such as BRCA1, BRCA2 or PTEN, raises risk. Chest radiation received for an earlier childhood lymphoma also raises the risk of a thoracic malignancy later in life.

In select cases, yes: for hormone receptor positive, node-negative early breast cancer, gene expression profile tests such as Oncotype DX and MammaPrint can show a low enough recurrence risk that chemotherapy can be safely skipped.

Age alone doesn't rule chemotherapy out. What matters more is the extent of disease and tumour biology, and a safe regimen can generally be offered at every age.