Ewing Sarcoma

Ewing sarcoma is a rare type of cancer that usually starts in the bones but can also occur in soft tissues. It most commonly affects children and young adults, often appearing in the long bones of the arms and legs, the pelvis, or the ribs. Early diagnosis and treatment are important for a better outlook.

What is Ewing Sarcoma?

Ewing sarcoma is a rare type of cancer that primarily develops in the bones, though it can also form in the soft tissues surrounding bones. This condition most often affects children and young adults, typically appearing in the long bones of the arms and legs, the pelvis, or the ribs.

Ewing sarcoma is part of a group of cancers called sarcomas, which are cancers of the connective tissues. It is considered very rare, accounting for a small percentage of all childhood cancers. While it can occur at any age, it is most frequently diagnosed in teenagers and young adults. The cancer cells in Ewing sarcoma grow quickly and can spread to other parts of the body, such as the lungs, other bones, or bone marrow. This spread is called metastasis. The exact location where the cancer starts can vary, but common sites include the thigh bone (femur), shin bone (tibia), upper arm bone (humerus), and the flat bones of the pelvis and chest wall.

Symptoms

The most common symptoms of Ewing sarcoma include persistent pain, swelling, or tenderness in the area where the tumor is located. You might also notice a lump, experience a fever, feel unusually tired, or lose weight without trying.

Pain is often the first symptom people notice. This pain can be constant, may worsen at night, or become more severe with activity. It might be mistaken for growing pains or a sports injury at first. Swelling or tenderness around the affected bone or soft tissue is another common sign. Sometimes, a noticeable lump or mass can be felt, especially if the tumor is close to the skin's surface. Other general symptoms can include a fever that doesn't go away, feeling very tired (fatigue), or losing weight without a clear reason. In some cases, the weakened bone might break (fracture) from a minor injury, which can be the first sign of the sarcoma.

Causes & risk factors

The exact cause of Ewing sarcoma is not fully understood, but it is linked to a specific genetic change that happens after birth and is not inherited. The main risk factors include age, as it primarily affects children and young adults, and race, being more common in people of Caucasian descent.

Ewing sarcoma is not caused by anything you or your child did, and it is not passed down through families (inherited). Scientists have found that nearly all Ewing sarcomas have a specific change in the genes of the cancer cells. This change is called a translocation, where pieces of two different chromosomes, usually chromosome 11 and chromosome 22, switch places. This genetic change leads to the production of an abnormal protein that is believed to drive the cancer's growth. While this genetic change is a key feature, it's not clear why it happens in some people and not others. The primary risk factor is age; most diagnoses occur in individuals between 10 and 20 years old, though it can affect younger children and adults. Another risk factor is race; Ewing sarcoma is more common in Caucasians (people of European descent) and less common in people of African or Asian descent.

How it's diagnosed

Diagnosing Ewing sarcoma typically involves a physical exam, various imaging tests to locate the tumor, and a biopsy to confirm the presence of cancer cells. A biopsy, which involves taking a tissue sample, is essential for a definitive diagnosis.

Your doctor will start with a physical exam and ask about your symptoms and medical history. If Ewing sarcoma is suspected, several imaging tests will be used to get a clear picture of the tumor. These tests may include X-rays, magnetic resonance imaging (MRI), computed tomography (CT) scans, positron emission tomography (PET) scans, and bone scans. These images help determine the tumor's size, exact location, and whether it has spread. The only way to confirm a diagnosis of Ewing sarcoma is through a biopsy. During a biopsy, a small sample of the tumor tissue is removed. This can be done with a needle (needle biopsy) or through a small surgical procedure (surgical biopsy). A specialist then examines the tissue under a microscope to identify cancer cells and perform genetic tests to look for the specific gene changes characteristic of Ewing sarcoma.

Treatment options

Treatment for Ewing sarcoma usually involves a combination of approaches, most commonly starting with chemotherapy to shrink the tumor and kill cancer cells throughout the body. This is often followed by surgery to remove the tumor and radiation therapy to destroy any remaining cancer cells.

Chemotherapy is almost always the first treatment given for Ewing sarcoma. It uses powerful drugs to kill cancer cells and is administered through an IV (intravenous line). Chemotherapy is given before surgery or radiation (neoadjuvant chemotherapy) to shrink the tumor, making it easier to remove, and to treat any cancer cells that may have spread but are not yet detectable. It is also given after surgery or radiation (adjuvant chemotherapy) to kill any remaining cancer cells. Surgery is performed to remove the tumor and a margin of healthy tissue around it. The type of surgery depends on the tumor's location and size. In some cases, limb-sparing surgery can remove the tumor while preserving the affected limb. If the tumor is in a limb and cannot be removed without leaving cancer cells, amputation might be necessary, though this is less common today. Radiation therapy uses high-energy beams to kill cancer cells. It may be used after surgery to destroy any cancer cells that could not be removed, or as the main treatment if surgery is not possible. For advanced cases where the cancer has spread or returned, high-dose chemotherapy followed by a stem cell transplant may be considered. This intensive treatment helps the body recover from the high doses of chemotherapy.

Recovery & outlook

The recovery and outlook for Ewing sarcoma depend significantly on whether the cancer has spread (metastasized) at the time of diagnosis. Early detection and treatment, especially when the cancer is localized (has not spread), generally lead to a better prognosis.

When Ewing sarcoma is found early and has not spread beyond its original site, the chances of successful treatment are higher. However, if the cancer has spread to other parts of the body, such as the lungs or other bones, the treatment becomes more challenging, and the outlook is generally less favorable. Recovery involves ongoing medical care, including regular follow-up appointments and imaging tests to monitor for any recurrence of the cancer. Patients may also need physical therapy or rehabilitation, especially after surgery, to regain strength and function. The emotional and psychological impact of cancer is also significant, and support services are often recommended. Advances in treatment, including more effective chemotherapy regimens and improved surgical techniques, have significantly improved survival rates over the years. Your medical team will discuss the specific outlook based on your individual situation, including the tumor's location, size, and how well it responds to treatment.

When to see a doctor

You should see a doctor if you or your child experience persistent bone pain, especially if it worsens at night or with activity, or if there is unexplained swelling, tenderness, or a noticeable lump. Also seek medical attention for unexplained fever, fatigue, or weight loss that doesn't improve.

While many aches and pains are not serious, it's important to have any concerning symptoms checked by a healthcare professional. Do not delay seeking medical advice if you notice a lump or mass that is growing or causing pain. If bone pain is severe, constant, or keeps you awake at night, it warrants an evaluation. Similarly, if there's swelling or tenderness around a bone or joint that doesn't go away, or if a bone breaks without a significant injury, these are important signs to discuss with a doctor. Early diagnosis is crucial for effective treatment of Ewing sarcoma.

Frequently asked questions

Is Ewing sarcoma hereditary?

No, Ewing sarcoma is not considered hereditary. It is caused by a genetic change (translocation) that happens after birth in the cancer cells themselves and is not passed down from parents to children.

What age group is most affected by Ewing sarcoma?

Ewing sarcoma most commonly affects children and young adults, with the majority of diagnoses occurring in individuals between the ages of 10 and 20 years old.

Can Ewing sarcoma be cured?

Yes, Ewing sarcoma can be cured, especially when it is diagnosed early and has not spread to other parts of the body. Treatment outcomes have significantly improved with modern combination therapies.

What are the long-term effects of Ewing sarcoma treatment?

Long-term effects can vary depending on the specific treatments received. They might include issues related to bone growth, fertility problems, or an increased risk of other cancers later in life. Regular follow-up care helps manage these effects.

How rare is Ewing sarcoma?

Ewing sarcoma is a very rare cancer. It accounts for a small percentage of all childhood cancers.

Does Ewing sarcoma always start in the bones?

While Ewing sarcoma most commonly starts in the bones, it can also originate in the soft tissues surrounding bones, such as muscle, fat, or fibrous tissue.

Sources

• MedlinePlus — Ewing Sarcoma
• Mayo Clinic — Ewing Sarcoma
• Cochrane Library — Ewing Sarcoma