Bone Tumors

A tumor is an abnormal tissue mass that forms when the cells in our body start dividing uncontrollably or do not die when they are supposed to. Tumors may be benign or malignant.

A benign tumor is a non-cancerous growth that does not intrude nearby tissues or spread to other parts of the body. A malignant tumor is cancerous destroying nearby tissues and can spread to other parts of the body.

The most common benign bone tumors are endochondroma, osteochondroma, nonossifying fibroma, chondroblastoma, osteoid osteoma, osteoblastoma, periosteal chondroma, giant cell tumor, and chondromyxoid fibroma.

Benign bone tumors occur most commonly among people below 30 years. They can develop in any bone but most commonly the femur, tibia, humerus and pelvis bone are involved. A lump or swelling that can be felt by touch is usually the first sign of a benign tumor. There will be increasing pain in the region of the tumor which persists over some time. In some cases, the tumor remains undiscovered until there is a fracture in the bone that has become weak from a growing tumor.

Bone sarcomas are cancerous tumors that develop in bones. Bone sarcomas may grow, compressing and destroying the healthy bone tissue.

Bone sarcomas are rare but the most common types include:

• Osteosarcomas
• Chondrosarcomas
• Ewing’s sarcoma

Osteosarcomas

Osteosarcoma is a common type of bone cancer that usually starts in the long bones of the arms and legs. It occurs in teenagers during the period of rapid growth and is more common in boys than girls. Osteosarcoma normally develops within the cells that form the bone tissue (osteoblasts).

Children with retinoblastoma (cancer of the eye) are at greater risk of developing osteosarcoma. Teenagers who are taller than average are predisposed to developing osteosarcoma. Children exposed to prior radiation treatment for cancer are also more likely to develop osteosarcoma. Adults may be at a higher risk if they have Paget’s disease or previous exposure to high doses of radiation therapy.

Chondrosarcomas

Chondrosarcoma is a malignant tumor that develops in the cartilage or the connective tissue covering the ends of the bones. Chondrosarcomas can occur both on and within a bone and most frequently affect the pelvic bones, shoulder bones, and the upper parts of the arms and legs. Most of these tumors are slow growing and can occur at any age. The incidence is found to be higher in males than females.

The cause of chondrosarcoma is unknown, but hereditary conditions such as Ollier disease, Maffucci syndrome, and hereditary multiple exostoses (HME) can enhance the risk of chondrosarcoma occurrence. People who have had chondroma (benign bone tumor) or an osteochondroma run the risk of developing chondrosarcoma.

Ewing’s Sarcoma

Ewing’s sarcoma is a malignant tumor that normally starts in the bone. It commonly affects teenagers and young adults who are transitioning through puberty. Ewing’s sarcoma starts in the bone, but it can also affect the soft tissues. This is known as extraosseous Ewing’s sarcoma. It can develop in any bone, but is most commonly found in the pelvis, thigh bone (femur) and shin bone (tibia).

The exact cause of this type of bone cancer is not known. However, changes in the cell’s chromosomes are thought to be the reason for Ewing sarcoma formation. These changes occur after birth and are not inherited.

Symptoms

Symptoms of bone cancer include persistent pain, swelling, or tenderness in the affected area. Bone pain may become worse during exercise or at night. Bones may become weak and can fracture. Tumors affecting the legs may cause a limp.

Diagnosis

Your doctor will ask about your family and medical history, perform a physical examination and may order certain procedures and tests to diagnose sarcoma. These may include:

• X-rays: X-rays of the affected area may be taken to find out the location, size and shape of the tumor
• Computerized tomography (CT) Scans: This is a procedure that uses cross-sectional images to evaluate whether the tumor has spread
• Magnetic resonance imaging (MRI): This test uses a magnetic field to create detailed images of the body
• Positron emission tomography (PET): A PET scan can show whether cancer has spread to other parts of the body
• Biopsy: A sample of tissue is removed from the tumor for laboratory testing to examine whether the tissue is cancerous

Treatment

Treatment of bone cancer is decided based upon the type, nature, extent of its spread, and the patient’s general health. Treatment options include surgery, radiation therapy, and chemotherapy.

Chemotherapy uses drugs or medications to destroy the cancer cells. It is administered prior to surgery to kill the tumor cells and shrink the tumor. It is also prescribed after surgery to kill any remaining cancer cells and prevent recurrence.

Surgical treatment involves removing the cancerous tissue and consists of techniques such as limb-salvage, or limb sparing surgery or in rare cases, amputation.

Limb-salvage surgery removes the cancerous bone and the affected muscle. The gap is filled with a bone graft or a specially designed metal prosthesis.

Amputation, the removal of a part or whole of the affected limb, may also be required if the cancer has spread from the bone to the surrounding blood vessels.

In certain cases radiation therapy that harnesses high energy radiation is indicated as treatment to destroy the cancer cells.