Bone metastasis

3D rendered CT of hip bone metastases

ScleroticMets

Metastasis sites for common cancers

Metastasis sites for common cancers#Summary

CT of hip bone metastases

Bone metastasis refers to the spread of cancer cells from their original (primary) site to the bone. It is a common occurrence in advanced cancers, particularly those of the breast, prostate, lung, and kidney. Bone metastases can lead to serious health complications, including pain, fractures, and hypercalcemia (high calcium levels in the blood), significantly impacting a patient's quality of life.

Causes and Pathophysiology

The process of bone metastasis involves several steps. Cancer cells detach from the primary tumor, invade the surrounding tissue, enter the bloodstream or lymphatic system, and travel to distant sites, where they can invade and grow in the bone tissue. This process is facilitated by interactions between cancer cells and the bone microenvironment, involving various cellular and molecular mechanisms. The RANK/RANKL/OPG pathway is one such mechanism that plays a crucial role in bone remodeling and is often exploited by cancer cells to promote bone destruction and metastasis.

Symptoms

Symptoms of bone metastasis vary depending on the location and size of the metastases but may include:

• Pain, often worsening with movement
• Fractures, due to weakened bone
• Spinal cord compression, leading to pain, weakness, or paralysis
• Hypercalcemia, causing nausea, vomiting, confusion, and lethargy

Diagnosis

Diagnosis of bone metastasis typically involves a combination of medical history, physical examination, and imaging tests. Common imaging tests include:

• X-rays, which can show bone changes
• Magnetic resonance imaging (MRI), providing detailed images of the bone and surrounding tissues
• Computed tomography (CT) scan, used to detect bone and soft tissue changes
• Bone scan, which involves injecting a radioactive substance to detect bone changes

In some cases, a biopsy may be performed to confirm the diagnosis and identify the type of cancer cells present.

Treatment

Treatment for bone metastasis aims to relieve symptoms, reduce complications, and improve quality of life. Options include:

• Pain management, using medications, radiation therapy, or surgical interventions
• Bisphosphonates or denosumab, to strengthen bones and reduce the risk of fractures
• Radiation therapy, to relieve pain and control tumor growth
• Surgery, to repair fractures or stabilize the bone
• Systemic therapies, such as chemotherapy, hormonal therapy, or targeted therapy, depending on the type of primary cancer

Prognosis

The prognosis for patients with bone metastasis varies widely and depends on factors such as the type of primary cancer, the extent of bone involvement, and the patient's overall health. While bone metastasis can significantly affect morbidity and mortality, advances in treatment have improved the management of symptoms and complications, contributing to better quality of life and extended survival for many patients.