Bone Tumour

Bone tumours are abnormal growths of tissue within the bone and can be either benign (noncancerous) or malignant (cancerous). Malignant bone tumours often originate from cancers in other parts of the body, such as the lung, breast, thyroid, kidney, and prostate.

These tumours may present with a variety of symptoms including lumps, pain, neurological signs due to pressure, and pathological fractures. Additional symptoms could include fatigue, fever, weight loss, anaemia, and nausea. In some cases, bone tumours are asymptomatic and discovered incidentally during investigations for other issues.

Classification

Bone tumours are classified by the World Health Organisation (WHO) into categories such as cartilage tumours, osteogenic tumours, fibrogenic tumours, vascular tumours of bone, osteoclastic giant cell-rich tumours, notochordal tumours, other mesenchymal tumours of bone, and hematopoietic neoplasms of bone. They can also be divided into primary tumours, which originate in the bone, and secondary tumours, which metastasize to the bone from other sites. Primary bone tumours can be benign, such as osteoma and osteoid osteoma, or malignant, such as osteosarcoma and Ewing sarcoma.

Signs and Symptoms

Clinical features of bone tumours vary depending on the type and location of the tumour. Common symptoms include:

• Lump with or without pain.
• Pain that worsens with tumour growth, at night, and at rest.
• Pathological fractures with minimal or no trauma.
• Additional symptoms: fatigue, fever, weight loss, anaemia, nausea.
• Neurological signs if a nerve is compressed.

Diagnosis

The diagnostic process often begins with a physical examination and a plain X-ray. Further investigations may include blood tests (complete blood count, inflammatory markers, serum electrophoresis, PSA, kidney and liver function tests, urine for Bence Jones protein), CT scans, MRI, PET scans, and bone scintigraphy. A biopsy, either needle or open, is usually required for histological evaluation.

Staging

Treatment

Treatment varies depending on the type of tumour. Specialist centres with a multidisciplinary team approach are often involved. Noncancerous tumours may be monitored and surgically treated if symptomatic. Malignant tumours may require surgical resection, chemotherapy, and radiotherapy.

Chemotherapy and Radiotherapy

Chemotherapy and radiotherapy are effective for some tumours like Ewing's sarcoma but less effective for others like chondrosarcoma. Various chemotherapy protocols exist, with intra-arterial protocols showing promising results.

Medication

Bone density and bone loss are major concerns. Non-hormonal bisphosphonates can increase bone strength, and Strontium-89 chloride can help manage pain.

Surgical Treatment

Surgical options include limb amputation or limb-sparing surgery, which might involve bone grafts or artificial bone implants. Other techniques include allograft, tumour-devitalized autograft, and custom-made implants. Joint preservation surgical options also exist, although they may yield lower functional scores compared to intra-articular resection.

Thermal Ablation Techniques

CT-guided radiofrequency ablation (RFA) has emerged as an effective treatment for benign bone tumours and palliative treatment for metastatic bone disease. Cryoablation, monitored by CT, offers another alternative, especially for tumours near very important structures.

Prognosis

Prognosis depends on the type of tumour. Benign tumours generally have a good outcome, while malignant tumours' outcomes vary based on type, location, and size. The average five-year survival rate in the US for bone and joint cancer is 67%.

Epidemiology

Primary bone tumours are rare, constituting about 0.2% of all tumours.

History

The earliest known bone tumour, an osteosarcoma, was found in a foot bone from Swartkrans Cave, South Africa, dating back 1.6-1.8 million years.

Other Animals

Bone tumours are also common in cats and dogs.

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Self-assessment MCQs (single best answer)

Which of the following is a common initial symptom of bone tumours?

What type of imaging is commonly used first in the diagnosis of bone tumours?

Which classification of bone tumours includes osteosarcoma?

Which of the following is a benign bone tumour?

What does the presence of pathological fractures with minimal trauma suggest about a bone tumour?

What is the five-year survival rate for bone and joint cancer in the US?

Which treatment technique involves CT-guided radiofrequency ablation?

Which of the following is a type of secondary bone tumour?

Which symptom is NOT typically associated with bone tumours?

Which of the following bone tumours is more responsive to chemotherapy?