Sites of Metastasis in Breast Cancer: Where Does it Spread?

Breast cancer, initially a localized condition, has the potential to invade surrounding tissues and ultimately metastasize to distant organs. The most common sites of metastasis in breast cancer include the bones, lungs, brain, and liver.

1. Bone Metastasis in Breast Cancer

Bone metastasis is the most prevalent, occurring in over 85% of cases. Breast cancer cells find bone tissue particularly hospitable for metastasis. This invasion can lead to bone destruction, resulting in conditions such as osteoporosis and, more critically, fragile and fractured bones.

Common areas for breast cancer metastasis to bones include the pelvis, lumbar spine, ribs, skull, and cervical vertebrae. Left untreated, bone metastasis can cause severe pain, disability, and even a risk to the patient's life. Late-stage breast cancer treatment often involves a combination of radiotherapy, chemotherapy, pain management, and endocrine therapy to improve outcomes.

2. Lung Metastasis in Breast Cancer

Following bone metastasis, lung metastasis ranks second in prevalence. Lung tumors originating from breast cancer are typically small (less than 3 cm), solid, and often located in the central regions of the lungs. Lung metastasis can lead to complications such as pneumonia, collapsed lungs, or pleural effusion.

Recognizing symptoms of lung metastasis in late-stage breast cancer can be challenging, as they may mimic common cold and flu symptoms. These include persistent cough, breathlessness, occasional coughing up of blood, loss of appetite, unintentional weight loss, fatigue, low energy levels, and sudden lung pain. Some breast cancer surgery patients may develop pneumonia in the weeks or months following surgery.

3. Brain Metastasis in Breast Cancer

Brain metastases account for approximately 18% of metastatic cases in postmenopausal women with breast cancer. Malignant breast cancer cells infiltrate the brain, typically targeting the gray and white matter or the sinuses and blood vessels. These metastases often distribute according to the brain's vascular supply, predominantly affecting the cerebral hemisphere (approximately 85% of cases).

When breast cancer metastasizes to the brain, it can manifest with various neurological symptoms, including headaches, neurological impairments, paralysis or sensory loss due to tumor growth, leading to brain swelling, blood vessel obstruction, and even stroke. Treatment options for brain metastasis may include surgery, chemotherapy, radiation therapy, and endocrine therapy, tailored to the patient's condition and the severity of the disease.

4. Liver Metastasis in Breast Cancer

Liver metastasis is typically observed in the advanced stages of breast cancer. Symptoms associated with breast cancer metastasizing to the liver include jaundice, abdominal pain, unexplained weight loss, and the appearance of unexplained bruises on the skin. Liver function can also be compromised.

In cases of breast cancer with liver metastases, treatment options may involve tumor ablation, embolization combined with chemotherapy, or standalone radiotherapy.

Breast cancer poses a significant threat to health, particularly when it reaches advanced stages with metastasis to various parts of the body, most commonly the bones, lungs, brain, and liver. Given the often silent progression of early-stage breast cancer, regular screening is crucial for early detection, accurate diagnosis, and prompt treatment, helping prevent the spread of the disease, which becomes increasingly challenging to manage at advanced stages.