Breast Cancer: Not One Disease, But Many

Breast cancer is a complex group of diseases with diverse biological behaviors, meaning two patients with similar-looking tumors on a mammogram can receive entirely different treatments. Oncologists now classify these cancers based on specific markers on tumor cells, primarily estrogen and progesterone receptors, and the HER2 protein. Tumors that are hormone-receptor positive may be treated with hormone-blocking therapies, while HER2-positive tumors can be targeted with specific drugs.

For some hormone-receptor-positive, HER2-negative tumors with a low risk of recurrence, chemotherapy may not be necessary, especially when supported by genomic tests. Conversely, triple-negative breast cancers, which lack these receptors and the HER2 protein, typically rely on chemotherapy, sometimes combined with immunotherapy or other targeted treatments. Treatment plans also consider the cancer's stage, including tumor size and spread to lymph nodes or other organs.

Beyond biology, a patient's overall health, age, inherited genetic mutations like BRCA1/BRCA2, and personal preferences are crucial factors. This holistic approach, known as personalized medicine, ensures treatments are evidence-based and suited to each individual's specific circumstances. The field is continuously advancing, aiming for increasingly precise therapies that maximize effectiveness and minimize toxicity.