Osteosarcoma

What is Osteosarcoma?

Osteosarcoma, also known as osteogenic sarcoma, is a type of bone cancer that begins in the cells that form bones. Osteosarcoma is usually found in the long bones, particularly the legs, although it can also occur in the arms. It is the most common type of primary bone tumor seen in children.

Types of Osteosarcoma

• High-grade osteosarcoma: This is the fastest-growing type, with unusual cells. This type of osteosarcoma is seen in children and teens. The most common kinds are:
  • Osteoblastic (The tumor has a bony matrix)
  • Chondroblastic (The tumor has a cartilaginous matrix)
  • Fibroblastic (The tumor has a fibrous or connective tissue matrix)
• Low-grade osteosarcoma: This subtype develops slowly, and the cells resemble normal bone cells.
• Intermediate-grade osteosarcoma: This is a rare type of osteosarcoma that is in between high and low-grade tumors. The most common type is periosteal or juxtacortical, which develops on the bone surface.

Causes of Osteosarcoma

Although the exact cause is unclear, osteosarcoma forms in the bone cells as a result of changes in the DNA or genetic code. These cells can invade and kill healthy body tissue and spread throughout the body. Some risk factors of osteosarcoma include:

• Previous treatment with radiation therapy
• Paget's disease of bone
• Fibrous dysplasia
• Rapid bone growth
• Bone infarction
• Certain genetic conditions, including hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, and Werner syndrome

Symptoms of Osteosarcoma

Signs and symptoms of osteosarcoma include:

• Swelling and tenderness in the bone
• Bone or joint pain
• Bone injury or break for no apparent reason
• Limping
• Pain after exercise
• Increased pain with lifting 
• Persistent fever
• Presence of a warm lump on the bone

Diagnosis of Osteosarcoma

Your doctor will review your medical history and symptoms and conduct a physical examination. The following diagnostic tests may be ordered:

• MRI Scan: This study uses a large magnetic field and radio waves to produce images that help in detecting damage to tissues such as bone, muscles, tendons, and ligaments. 
• CT Scan: This scan uses multiple X-rays to produce detailed cross-sectional images of the body.
• X-rays: This study uses electromagnetic beams to produce images of the bones and can detect fractures or bony abnormalities.
• Ultrasound: This study uses high-frequency sound waves to produce images of hard and soft tissue.
• Bone scan: This study uses a tiny amount of a radioactive substance to visualize the damage to the bones.
• Bone Biopsy: This is an image-guided procedure in which a small sample of bone tissue is taken and observed under a microscope. Types of biopsy procedures used to diagnose osteosarcoma include:
  • Needle biopsy: A tiny needle is inserted through the skin and guided into the tumor by the doctor. The needle is used to remove small pieces of tissue from the tumor to examine under a microscope.
  • Surgical biopsy: The doctor makes an incision through the skin and removes all or part of the tumor for examination in a lab.

Treatment for Osteosarcoma

Common treatment options for osteosarcoma include:

• Surgery: The extent of surgery for osteosarcoma depends on several factors, such as the size of the tumor and its location. The various procedures used to treat osteosarcoma include:
  • Surgery to remove cancer only (Limb-sparing surgery): Most osteosarcoma operations can be performed in such a way that all tumors are removed while the limb is spared, and function is maintained. The surgeon will repair the bone if a part of it is removed. Metal prostheses or bone grafts are two choices for reconstruction, depending on your specific situation.
  • Surgery to remove the affected limb (amputation): The surgeon may need to remove all or part of a limb. You may choose to get fitted for an artificial or prosthetic limb after recovery.
  • Rotationplasty: This is a procedure in which the surgeon performs an excision above the knee joint. The lower part of the leg is then reattached with the foot and ankle turned so that the ankle acts as the new knee joint. The lower leg and foot are supported by a prosthesis.
• Radiation therapy: Radiation therapy uses high-powered energy beams such as X-rays or protons to kill cancer cells.
• Chemotherapy is a drug treatment that involves one or more anti-cancer drugs to kill cancer cells. Chemotherapy drugs can be given in pill form, administered through a vein, or both. For osteosarcoma treatment, chemotherapy is usually done before the surgery as this helps the tumor to shrink in size.