Osteosarcoma is a type of cancer that forms in the bone. It affects people of all ages, but the risk is highest during youth. Symptoms may include bone pain and swelling, and treatment is with a combination of surgery and chemotherapy. When the disease is caught before it spreads, and when the tumor can be surgically removed, the cure rate may be as high as 75 percent.
Significance
Bone cancer overall is rare, but osteosarcomas account for more than one-third of all bone cancer case, according to the Mayo Clinic. The disease is most common between the ages of 10 and 30, but it can occur at any age. According to the National Institutes of Health, osteosarcoma is the most common malignant bone tumor in children, and the average age of diagnosis is 15 years. Boys and girls are affected equally until adolescence, after which time boys are at an increased risk of developing the cancer. Only about 900 new cases are diagnosed each year in the United States, with 400 of these cases occurring in children. Only about 10 percent of osteosarcomas form in those over the age of 60 years, according to the American Cancer Society.
Features
Osteosarcoma cells produce bone matrix just like osteoblasts of healthy bone, but the bone tissue is not as strong as that produced by normal bones. Osteosarcoma usually develops near the ends of the long bones, but may form anywhere and can spread into nearby tissues. Approximately 80 percent of osteosarcomes form in the distal femur, which is the part of the thigh bone nearest the knee, or in the proximal tibia, which is the portion of the lower leg bone near the knee. Osteosarcomas are classified as low-grade, intermediate-grade or high-grade tumors, depending on the quantity of dividing cells inside the tumor itself.
Causes
Osteosarcoma sometimes runs in families, and one gene in particular has been linked to higher risk of developing the bone cancer, according to the National Institutes of Health. This gene, called the retinoblastoma (Rb) tumor suppressor gene, is also associated with familial retinoblastoma, a childhood eye cancer. However, the American Cancer Society states that most cases of osteosarcoma do not result from a DNA mutation.
Symptoms
Tenderness, swelling and redness may develop at the site of tumor. Depending on the location of the tumor, the patient may experience a limited range of motion in the affected limb, may walk with a limp or feel pain when lifting. The pain is generally worse at night or during exercise. A bone fracture may occur following routine movement. The National Cancer Institute states that any pain or swelling in a bone should be evaluated with blood tests and X-rays. If these tests do not detect an alternative cause for the pain or swelling, doctors should suspect osteosarcoma and make a referral to an orthopedic oncologist for a biopsy.
Treatment
A surgical biopsy is necessary to confirm a diagnosis of osteosarcoma. Treatment generally involves a combination of surgery to remove the primary tumor and chemotherapy to kill any cancer cells that have spread throughout the body. Common chemotherapy medications used in the treatment of osteosarcoma include doxorubicin, methotrexate and cisplatin. The medications are usually given in high doses, sometimes in conjunction with ifosfamide, to increase effectiveness. Surgery may involve removal of the tumor or amputation of the affected limb. The American states that limb-salvage surgery is possible in as many as 80 percent of cases, but rehabilitation may take a year or longer. Radiation is not a common treatment for osteosarcoma.
Prognosis
According to the National Cancer Institute, the chance of recovery following a diagnosis of osteosarcoma depends on multiple factors, including the size and location of the tumor, the stage of the disease, the patient's age, the specific type of osteosarcoma cells present and the results of certain blood tests. St. Jude Children's Research Hospital states that the current overall five-year survival rate of osteosarcoma patients is 65 percent. Localized osteosarcoma is curable approximately 75 percent of the time, but the cure rate drops to 30 percents for those with metastatic osteosarcoma. When a tumor occurs in a location where it cannot be removed, such as on the spine, a cure is not likely.
Tags: states that, American Cancer, American Cancer Society, Cancer Society, pain swelling, According National