Ewing's Sarcoma

Definition

Ewing's sarcoma is a cancer that affects children, teens, and less often, young adults. It begins in developing bone cells. Ewing's sarcoma cells grow uncontrollably and form masses or lumps called tumors. They can start in any bone in the body but about half of all cases involve flat bones such as the pelvic bones and the long bones in the leg-the tibia, fibula, and femur.

Description

Ewing's sarcoma is the second most common bone tumor among children and teens. It accounts for about 1% of all childhood cancers. This cancer is named for James Ewing, the researcher who first described the tumor in 1921. There are some rare cases of Ewing's sarcoma that do not begin in bones. These tumors are thought to start in nerve or other soft tissues.

Demographics

Ewing's sarcoma occurs most frequently in children ages 11 to 15 years old. Slightly more males than females develop Ewing's sarcomas, and like osteosarcoma, the most common bone cancer found in children, it is more often diagnosed in taller teens. The disease is rarely diagnosed in children younger than 5 or adults older than 30. It affects primarily Caucasians, and rarely occurs in African Americans and native Chinese.

Causes and symptoms

The causes of Ewing's sarcoma are not known. It is possible that certain inherited conditions increase the risk of developing this cancer.

About two-thirds of patients with Ewing's sarcoma have a painful swelling or lump that can be felt in the affected bone. Along with tenderness, the area of swelling may be hot. The symptoms depend on the site of the tumor and whether it has spread. For example, a tumor on a rib may cause painful breathing. When Ewing's sarcoma has spread, patients may have other symptoms such as fatigue, weight loss, and fever.

Diagnosis

Most patients who have Ewing's sarcomas go to the doctor because they have discovered a lump or mass or swelling on or near a bone. Others have symptoms related to the part of the body that is affected by the tumor, such as pressure on the bladder from a tumor on a pelvic bone.

The patient's doctor will take a detailed medical history to find out about the symptoms. The history is followed by a complete physical examination with special attention to the suspicious symptom or body part.

Depending on the location of the tumor (mass or lump), the doctor will order imaging studies such as x ray, computed tomography (CT) scans and magnetic resonance imaging (MRI) to help determine the size, shape and exact location of the tumor. The doctor will also order a chest x ray to find out if the tumor has spread to the lungs, and bone scans to determine if the tumor has spread to bones. Blood tests will be done and an examination of the bone marrow will be performed to see if the marrow is involved.

A biopsy of the tumor is necessary to make a diagnosis of Ewing's sarcoma. During a biopsy, some tissue from the tumor is removed. The tissue sample is examined by a pathologist, a doctor who specializes in the study of diseased tissue.

Types of biopsy

The type of biopsy done depends on the location of the tumor. For some small tumors, such as those on the arm or leg, the doctor may perform an excisional biopsy, removing the entire tumor and a margin of surrounding normal tissue. Most often, the doctor will perform an incisional biopsy, a procedure that involves cutting out only a piece of the tumor. This biopsy provides a core of tissue from the tumor that is used to confirm the diagnosis of Ewing's sarcoma.

Treatment team

Like other cancer patients, teens and young adults with Ewing's sarcoma are usually cared for by a multidisciplinary team of health professionals. The patient's pediatrician, family physician, or primary care doctor may refer the patient to other physician specialists, such as surgeons and oncologists (doctors who specialize in cancer medicine). Radiologic technicians perform x ray, CT and MRI scans and nurses and laboratory technicians may obtain samples of blood, urine and other laboratory tests.

Before and after any surgical procedures, including biopsies, specially trained nurses will explain the procedures and help to prepare patients and families. Depending on the tumor location and treatment plan, patients may also benefit from rehabilitation therapy with physical therapists and nutritional counseling from dieticians.

Clinical staging, treatments, and prognosis

Staging

The purpose of staging a tumor is to determine how far it has advanced. This is important because treatment varies depending on the stage. Generally, stage is determined by the size of the tumor, whether the tumor has spread to nearby lymph nodes, whether the tumor has spread elsewhere in the body, and what the cells look like under the microscope.

There is no commonly accepted system for staging Ewing's sarcomas. As is the case with other cancers, patients with metastases (spread) tend to have worse outlooks than patients whose tumors have not spread.

Between one quarter to one third of patients with Ewing's sarcoma have metastases when they are first diagnosed. Patients with tumors closer to the trunk of the body or in the pelvic bones are more likely to have metastases than patients with tumors located on the lower leg or foot. The most common sites for spread of Ewing's sarcoma are to the lungs or bones.

Treatment

Treatment for Ewing's sarcoma varies depending on the location of the tumor, its size and grade, and the extent of its spread. For most patients, the goals of treatment are to remove or control the tumor and combat the spread of the cancer.

Generally, when removing the tumor will not sharply reduce function, Ewing's sarcoma tumors are surgically removed. The goal of removing as much tumor as possible is to reduce the amount of radiation needed after surgery. The part of the body where the tumor was removed is treated with radiation to destroy remaining tumor cells. Most patients also receive chemotherapy, powerful anti-cancer drugs to destroy remaining cancer cells.

When the disease has spread throughout the body, there may be no benefit from surgical removal of the tumor. These patients, who have widespread metastases, are treated with radiation and chemotherapy.

Side effects

The surgical treatment of Ewing's sarcoma carries risks related to the surgical site, such as loss of function resulting from loss of a long bone in the leg. There also are the medical risks associated with any surgical procedure, such as reactions to general anesthesia or infection after surgery.

The side effects of radiation therapy depend on the site being radiated. Radiation therapy can produce side effects such as fatigue, skin rashes, nausea and diarrhea. Most of the side effects lessen or disappear completely after the radiation therapy has been completed.

The side effects of chemotherapy vary depending on the medication, or combination of anticancer drugs, used. Chemotherapy drugs often given to combat Ewing's sarcoma are cyclophosphamide, doxorubicin, vincristine, and dactinomycin.

For patients with widespread disease, chemotherapy may be given along with bone marrow transplant and radiation to the entire body. Nausea and vomiting, anemia, lower resistance to infection, and hair loss (alopecia) are common side effects of chemotherapy. Medication may be given to reduce the unpleasant side effects of chemotherapy.

Alternative and complementary therapies

Many patients find that alternative and complementary therapies help to reduce the stress associated with illness, improve immune function and feel better. While there is no evidence that these therapies specifically combat disease, activities such as biofeedback, relaxation, therapeutic touch, massage therapy and guided imagery have been reported to enhance well-being.

Prognosis

The outlook for patients with Ewing's sarcoma varies, depending on the size and volume of the tumor, its stage, and the extent of its spread. Patients with large tumors do not fare as well as those with smaller tumors. Patients with tumors in certain sites, such as the bones of the pelvis and spinal column also seem to have poor outlooks because by the time these tumors are discovered they have already spread.

Ewing's sarcoma may spread locally to areas near the tumor and it can spread to nearby lymph glands. To spread to distant parts of the body, the cancer cells travel in the blood, bone marrow or through the lymph glands. In general, tumors that have spread widely throughout the body are not associated with favorable survival rates.

Nearly three quarters of patients diagnosed before the cancer has spread are disease free for five years after treatment. Patients with tumors that do not respond to treatment and those who suffer recurrences have poor outlooks for long-term survival.

Coping with cancer treatment

Teens undergoing cancer treatment have special needs. The diagnosis of a life-threatening illness, surgery and radiation or chemotherapy may cause fear, anxiety, depression and loss of self-esteem. Disruption of normal routines and discomfort from diagnostic tests and treatment may also cause anxiety. There are additional social problems including making up missed school work, explaining the illness and treatment to friends, and coping with physical limitations or disability.

Teens with serious illnesses and disabilities face emotional conflicts and psychological challenges. One conflict is between the teen's growing desire for independence and the reality of dependence on others for the activities of daily living. It is important for teens to be fully informed about their disease and treatment plan and involved in treatment decision making. Many teens benefit from continuing contact with friends, classmates, teachers, and family during hospital stays and recovery at home.

Depression, emotional distress, and anxiety associated with the disease and its treatment may respond to counseling from a mental health professional. Individual and group therapy often help teens and young adults to reveal and express their feelings about illness and treatment. Many cancer patients and their families find participation in mutual aid and group support programs help to relieve feelings of isolation and loneliness. By sharing problems with others who have lived through similar difficulties patients and families can exchange ideas and coping strategies.

Clinical trials

More than 25 clinical studies were underway during 2001. For example, at John Hopkins Oncology Center and other cancer centers across the United States, patients with recurring or widespread Ewing's sarcoma were being given chemotherapy to stop tumor cells from dividing as well as stem cells (bone marrow transplantation) to replace immune cells killed by chemotherapy.

Other clinical trials compare different combinations of drugs used for chemotherapy or combinations of chemotherapy and radiation to find out which combination is more effective. For example, in one study, patients with Ewing's sarcoma were randomly assigned to two different treatment groups. One group received chemotherapy followed by surgery and radiation therapy. The other group received radiation therapy during chemotherapy.

Other types of clinical research study individuals and families at high risk of cancer to help identify cancer genes. To learn more about clinical trials visit the National Cancer Institute (NCI) web site at http://cancertrials.nci.nih.gov or the Pediatric Oncology Branch of the National Cancer Institute web site at http://www-dcs.nci.nih.gov/pedonc/

Prevention

Since the causes of Ewing's sarcoma are not known, there are no recommendations about how to prevent its development. Among families with an inherited tendency to develop soft tissue sarcomas, careful monitoring may help to ensure early diagnosis and treatment of the disease.

Special concerns

Ewing's sarcoma, like other cancer diagnoses, may produce a range of emotional reactions in patients and families. Education, counseling and participation in group support programs can help to reduce feelings of guilt, fear, anxiety and hopelessness. For many parents suffering from spiritual distress, visits with clergy members and participation in organized prayer may offer comfort.

KEY TERMS

Biopsy

The surgical removal and microscopic examination of living tissue for diagnostic purposes.

Chemotherapy

Treatment of cancer with synthetic drugs that destroy the tumor either by inhibiting the growth of cancerous cells or by killing them.

Metastasize

The spread of cancer cells from a primary site to distant parts of the body.

Oncologist

A doctor who specializes in cancer medicine.

Pathologist

A doctor who specializes in the diagnosis of disease by studying cells and tissues under a microscope.

Radiation therapy

Treatment using high energy radiation from x-ray machines, cobalt, radium, or other sources.

Stage

A term used to describe the size and extent of spread of cancer.

QUESTIONS TO ASK THE DOCTOR
• How big is the tumor?

• Has the Ewing's sarcoma spread?

• What are the recommended treatments?

• What are the side effects of the recommended treatments?

• Is treatment expected to cure the disease or only to prolong life?