Sarcoma Facts

The term, sarcoma, comes from a Greek word meaning "fleshy growth." While sarcomas can develop in any part of the body, half of them develop in the arms or legs. The rest develop in the trunk, head and neck area, internal organs, or the retroperitoneum (the back of the abdominal cavity).

There are close to 10,000 new cases of sarcoma diagnosed in the United States each year, representing just one percent of all cancer cases. The majority of the cases (close to 8,000) are soft-tissue sarcomas; the other 2,000 or so are bone cancers. Patients with a soft-tissue sarcoma typically present with a painless, firm, soft-tissue mass, while patients with osseous sarcomas present with pain.

The typical diagnostic delay varies from three to 12 months, depending on the anatomic location of the tumor and the care received.

A sarcoma is a tumor that arises out of connective tissues, not glandular tissues. Sarcomas, therefore, are found in bone (osseous), cartilage, skeletal muscle, tendons, veins/arteries, nerves, skin, and fatty tissues.

Risk Factors

Risk factors include high-grade tumors, tumors larger than 10 cm in size, tumors with metastatic disease, and certain sarcoma subtypes. Subtypes include histologic and molecular markers that are sometimes linked to tumor types that prove to be more aggressive and resistant to chemotherapy.

Symptoms

Symptoms occur in and around the joints, often causing swelling and tenderness. Bone tumors can weaken the bones, thus causing fractures. Other symptoms include weight loss, fatigue, anemia, or pain without any clear source of injury. Symptoms usually do not show up until the disease is advanced, but a doctor should be contacted regarding the following symptoms: a new or growing lump appears, increasing abdominal pain, and/or blood in stools or in vomit.

Diagnosis

Soft-tissue sarcomas are diagnosed through a surgical biopsy. The grade of the tumor is determined by how abnormal the cancer cells appear when examined under a microscope. Low-grade sarcomas, although cancerous, are unlikely to metastasize. High-grade sarcomas are more likely to spread to other parts of the body. For bone cancers, the doctor may suggest a blood test to determine the level of an enzyme called alkaline phosphatase; a high level can be found when there is a disease or tumor. High levels of this enzyme can also be found in children and adolescents with growing bones, so the test is not a reliable determination of bone cancer. Bone cancers are also diagnosed by X-rays and imaging tests, such as a bone scan, an MRI, or an angiogram. Regardless of how bone cancer is initially diagnosed, a biopsy is still needed to confirm whether or not cancer is present.

Adult patients over the age of 40 years who present with a bony abnormality or bone tumor should be further evaluated for an unknown primary tumor of lungs, kidneys, breast, or prostate.

Types of Sarcomas

Sarcomas are divided into two main categories:

• Bone tumors
• Soft-tissue sarcomas

Sarcomas are further subclassified based on the specific type of cell that makes up the cancer. This is known as the sarcoma, or histologic, subtype. There are more than 50 different types of soft-tissue sarcomas, more than half of which are malignant. The natural history or behavior of any particular sarcoma will be determined by the histologic or molecular subtype, and histologic grade.

The most common type of bone cancer is osteosarcoma. Because it occurs in growing bones, it is most often found in teenagers. Osteogenic sarcoma is one of the few cancers that begins in the bone and spreads elsewhere. Other bone sarcomas that begin in bone include Ewing's sarcoma.

Subtypes of Sarcomas

The most common subtypes of sarcoma include:

• Angiosarcoma Malignant tumor that resembles blood or lymphatic vessels
• Chondrosarcoma Tumor of cells that form cartilage
• Ewing's Sarcoma Class of disease that arises from very primitive cells in the body
• Fibrosarcoma Cancer of the fibroblast-type cells in the body; fibroblast-type cells form scars, and do other important connective functions
• Gastrointestinal Stromal Tumor Increasingly recognized diagnosis of connective tissue cancerous cells that support the gastrointestinal tract
• Kaposi's Sarcoma Tumor of cells found in the tissues under the skin or mucous membranes that line the mouth, nose, and anus. Kaposi's sarcoma causes red or purple patches on the skin and/or mucous membranes, and spreads to other organs in the body. Approximately 95 percent of all of cases of Kaposi's sarcoma in the United States have been diagnosed in homosexual or bisexual men.
• Liposarcoma Malignant tumor that develops from fat tissue; most often in the retroperitoneum (tissue at the back of the abdominal cavity), but can also be found in the soft tissues of the limbs.
• Leiomyosarcoma Malignant tumor that develops from smooth muscle tissue found in abdominal and pelvic organs and blood vessels. (Unlike skeletal muscle, which you can contract voluntarily, your brain doesn't have conscious control over smooth muscle.)
• Malignant Peripheral Nerve Sheath Tumor Arises out of nerves or nerve tissue outside of the brain and spine.
• Osteosarcoma Tumor of cells that form bone
• Rhabdomyosarcoma Malignant tumor that resembles developing skeletal muscle. Most commonly grows in the arms and legs, but can also develop in the head or neck area, as well as the urinary and reproductive organs. Rhabdomyosarcoma accounts for more than half of all the soft-tissue sarcomas diagnosed in children. Most children are diagnosed at less than nine years of age, but rhabdomyosarcoma can occur at any age.
• Synovial Sarcoma Malignant tumor made up of cells that resemble the cells found in joints (synovial cells line the joints). Synovial sarcoma can arise in any location in the body, and often appears in young adults.

Sarcobase

Created by University of Washington medical oncologist, Dr. Ernest Conrad, Sarcobase helps in researching this rare form of cancer.

Sarcobase is a unique tumor registry for sarcoma patients who have been treated at Seattle Cancer Care Alliance (SCCA) or its parent organizations, Children's Hospital and Regional Medical Center and UW Medical Center.

Dr. Ernest Conrad, medical oncologist at UW Medical Center and director of the Sarcoma Service, started Sarcobase in 2000, and more than 450 patients are now listed in the registry.

Sarcoma patients who enroll in Sarcobase can be tracked for follow-up and also for clinical research. "It's the only reliable way we have to track people," says Dr. Conrad. Patients' data and their privacy are protected as required by national regulations of the Health Insurance Portability and Accountability Act (HIPAA).

The data collected in Sarcobase will benefit future sarcoma patients, making it a valuable tool for patient education. Researchers are using this information to learn more about sarcomas, which are rare cancers of the bone and connective tissues.

Sarcobase addresses the need for more research on this rare group of diseases by providing important information on a large number of sarcoma patients, making it a valuable resource for understanding the disease.