Chondrosarcoma

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Chondrosarcoma

Definition

Chondrosarcoma is a malignant tumor that produces a special type of connective tissue called cartilage. Malignant tumors have cells that have the ability to invade and are characterized by uncontrolled growth.

Description

Cartilage is a type of connective tissue that acts as a resistant surface. Cells called chondrocytes produce cartilage. Chondrosarcoma is a malignant growth arising in chondrocytes. There are two types of chondrosarcomas, either primary or secondary. Primary chondrosarcomas arise in areas of previously normal bone that are derived from cartilage. Secondary chondrosarcomas are lesions produced from pre-existing cartilage lesions. The chondrosarcoma tumors either produce enlargement or erosion of the area involved. The lesion is classified further as to where the lesion occurs and the grade of the lesion. It is graded from 1 (low-grade) to 3 (high-grade). This classification states that the higher the grade of the tumor, the higher the increased atypia, or abnormal cell growth.

Two non-cancerous diseases, Maffuci disease and Ollier disease, are similar to chondrosarcoma. Ollier disease, also known as enchondromatosis or dyschondroplasia, is a disorder affecting the growth plates of bone where new bone is deposited. The cartilage laid down is not reabsorbed and masses form near the ends of the long bones such as the thigh bone (femur) and upper arm bone (humerus). Maffucci disease has the same abnormalities as Ollier disease as well as soft tissue destruction including the skin. Patients with Maffucci or Ollier disease should have bone scans every three to five years to monitor potential malignant transformations.

Genetic profile

Anomalies of chromosomes 5, 7, 8, and 18 and structural alterations of chromosomes 1, 12, and 15 are commonly found in patients diagnosed with chondrosarcoma. Interestingly, the gene for the area of normal cartilage production, type II collagen, has been found in the same regions as chondrosarcoma. Studies on the tumor suppressor gene, EXT1, have shown that changes (mutations) of this gene may also be important in the growth of chondrosarcoma.

Demographics

In 2001, an estimated 2,900 new cases of bone and joint cancer were diagnosed. Primary cancer of bones accounts for less than 0.2% of all cancers. Chondrosarcoma is the second most common primary malignant bone tumor, meaning it did not originate at another site in the body. Osteosarcoma is the first most common.

There are conflicting reports as to how much more frequently men are diagnosed with chondrosarcoma than females. Findings range from twice as many males to only slightly more males than females. Chondrosarcoma occurs in people from the age of 30-70 years old, but it most commonly affects people over the age of 40. No ethnic group is affected more frequently than another.

Signs and symptoms

The signs and symptoms vary due to the type of tumor, but pain is typically the first symptom. If it is a fast growing, high grade form of chondrosarcoma, then the individual may have very severe pain. A low grade, slow growing, tumor usually has pain and swelling in the area of the tumor. If the tumor is located in the pelvis or hip area, the individual may have difficulty with urination or urinary urgency. The patient may also have the sensation of a groin pull if the tumor is in the pelvic area.

Diagnosis

Usually, chondrosarcoma is diagnosed with x ray radiography. X rays can show soft tissue calcification, where the muscles appear to be forming bone. The appearance of a soft tissue mass that has not yet calcified may also be visible. If the chondrosarcoma is secondary to another type of tumor, the chondrosarcoma may start to erode the edges of the other tumor. This is common where an enchondroma, a type of tumor within the bone shaft, is present. In this case, the chondrosarcoma produces areas of lysis, or destruction of the surrounding tissue.

Biopsy is used to determine the grade of the tumor. Grade 1 chondrosarcomas, or low-grade slow growing lesions, have a mild increase of new cell growth. Grade 3 chondrosarcomas are the opposite; they are high-grade, fast growing and have a dramatic increase in cellular growth. The more radiolucent or transparent to x rays the tumor appears, the greater the chance it is a higher grade.

Other imaging tests may also be used. Computed tomography scanning, CT, is an advanced form of x ray that can also produce bone pictures and help determine how much calcification the tumor is producing. Magnetic resonance imaging, MRI, will aid diagnosis since it can differentiate soft tissues such as muscle and fat. MRI will help determine the amount of malignant degeneration of the chondrosarcoma.

Treatment and management

The main course of therapy for chondrosarcoma is surgical removal of the tumor. The amount of surgery depends on the location and the stage of the tumor. Very low-grade tumors may be surgically removed. High-grade chondrosarcomas necessitate more radical operations where normal tissue is also removed due to the possibility of spread. If the tumor is located in an extremity such as an arm or leg, then amputation, or surgical removal of the extremity, may be necessary in order to prevent metastasis, or spread of the cancer. Chemotherapy and radiotherapy may also be used depending on the type of tumor and the area of the body affected, but are usually not effective.

Prognosis

The higher the grade of a chondrosarcoma, the more likely the tumor will spread and thus worsen the prognosis. One study found the five year survival rate of patients with grades 1, 2, and 3 to be 90%, 83%, and 43% respectively. This means that five years after the diagnosis of the tumor, 90 out of 100 people with grade 1 were still alive. On the opposite spectrum, 43 out of 100 patients with grade 3 chondrosarcoma survived five years. Therefore the survival rate is very much dependent on the stage of the tumor and also on its location. Size of the tumor is also an important factor. Tumors greater than 4 in (10 cm) are more likely to become aggressive and spread. When they do spread, or metasta-size, they often migrate to the lungs and skeleton.

Resources

BOOKS

Bridge, Julia A., et. al. "Sarcomas of Bone." In Clinical Oncology, 2nd ed. Edited by Martin D. Abeloff et. al. Philadelphia: Churchill Livingstone, 2000.

Levesque, Jerome, et al. A Clinical Guide to Primary Bone Tumors. Baltimore: Williams & Wilkins, 1998.

Rosenberg, Andrew E. "Skeletal System and Soft Tissue Tumors." In Robbins Pathologic Basis of Disease, 5th ed. Edited by Ramzi S. Cotran, Vinay Kumar, Stanley Robbins, and Frederick J. Schoen. Philadelphia: W. B. Saunders Company, 1994.

ORGANIZATIONS

American Cancer Society. Bone Cancer Resource Center. 1599 Clifton Road, NE, Atlanta, GA 30329. (800) 227-2345 or (404) 320-3333. <http://www.cancer.org/>.

Cancernet. National Cancer Institute, National Institutes of Health. NCI Public Inquiries Office, Building 31, Room 10A03, 31 Center Dr., MSC 2580, Bethesda, MD 20892-2580 USA.