How Ewing Sarcoma Is Diagnosed

Ewing sarcoma is a rare type of cancer that often begins in bones or soft tissue. Diagnosing Ewing sarcoma involves a series of tests, including imaging scans and biopsies, to identify the tumor and determine its characteristics. Early and accurate diagnosis is crucial for planning effective treatment and improving outcomes for individuals affected by this condition.

What is Ewing Sarcoma and why is its diagnosis important?

Ewing sarcoma is a rare and aggressive cancer that typically affects bones, but can also occur in soft tissues. Its diagnosis is a complex process involving multiple tests to confirm the presence of cancer, identify its type, and determine how far it has spread. An accurate and timely diagnosis is vital for starting the most appropriate treatment plan and improving the chances of a successful outcome.

Ewing sarcoma is part of a group of cancers known as Ewing family of tumors. It most commonly develops in the long bones of the arms and legs, the pelvis, or the chest wall. However, it can appear in any bone or, less often, in the soft tissues surrounding bones. This cancer is more frequently seen in children and young adults. Because Ewing sarcoma is rare, its symptoms can sometimes be mistaken for more common conditions, such as sports injuries or infections. This can sometimes lead to delays in diagnosis. The diagnostic process aims to distinguish Ewing sarcoma from other conditions and to gather detailed information about the tumor. A precise diagnosis is essential for several reasons. It guides doctors in choosing the most effective treatment strategy, which often involves a combination of therapies. It also helps predict the likely course of the disease (prognosis) and allows healthcare teams to monitor the patient's response to treatment.

Symptoms of Ewing Sarcoma

The symptoms of Ewing sarcoma can vary depending on where the tumor is located, but they often include pain and swelling in the affected area. Other general symptoms like fever, fatigue, and unexplained weight loss may also occur. These signs are often non-specific, meaning they can be caused by many different conditions, making diagnosis challenging.

The most common symptom of Ewing sarcoma is persistent pain in the area where the tumor is growing. This pain might worsen at night or with activity. Over time, a noticeable swelling or a lump may develop in the affected bone or soft tissue. This lump might feel warm to the touch. If the tumor is in a bone in the leg, it might cause a limp. If it's in the spine, it could lead to weakness, numbness, or even paralysis in parts of the body. Tumors in the ribs or chest wall can cause breathing difficulties. Beyond localized pain and swelling, some individuals may experience more general symptoms. These can include a fever that doesn't go away, feeling very tired (fatigue), and losing weight without trying. These systemic symptoms are less common but can indicate a more advanced stage of the disease.

Causes and Risk Factors for Ewing Sarcoma

The exact cause of Ewing sarcoma is not fully understood, and it is not considered to be an inherited condition. It develops from changes in the DNA of cells, but what triggers these changes is unknown. The primary risk factor is age, as it most commonly affects children, adolescents, and young adults, with cases rarely occurring in older adults.

Ewing sarcoma is believed to start when specific genetic changes occur in certain cells, leading them to grow out of control and form a tumor. Scientists have identified a particular genetic rearrangement, often involving chromosomes 11 and 22, that is present in most Ewing sarcoma cells. This change creates a fusion gene called EWSR1-FLI1. However, why these genetic changes happen in the first place is not known. Unlike some other cancers, Ewing sarcoma is not linked to lifestyle factors like diet or smoking, nor is it typically passed down through families (hereditary). This means that having a family member with Ewing sarcoma does not significantly increase your risk of developing it. The main risk factor identified is age. Ewing sarcoma is most common in children and teenagers, with the majority of diagnoses occurring between the ages of 10 and 20. It is rare in very young children and adults over 30. While anyone can develop Ewing sarcoma, it is slightly more common in males than females.

How Ewing Sarcoma Is Diagnosed

Diagnosing Ewing sarcoma involves a comprehensive approach, starting with a physical exam and medical history. Doctors then use various imaging tests to locate the tumor and assess its size and spread. A definitive diagnosis requires a biopsy, where a tissue sample is taken from the tumor and examined under a microscope, often with specialized genetic tests.

The diagnostic process usually begins when a person reports symptoms like persistent pain or swelling to their doctor. The doctor will perform a physical examination, checking for lumps, tenderness, and any limitations in movement. They will also ask about the patient's medical history and the duration and nature of their symptoms. **Imaging Tests:** Several imaging tests are crucial for identifying the tumor and determining its characteristics: * **X-ray:** Often the first test, an X-ray can show changes in bone structure, such as bone destruction or new bone formation, which might suggest a tumor. * **Magnetic Resonance Imaging (MRI):** An MRI provides detailed images of soft tissues and bones. It helps doctors see the exact size and location of the tumor, its relationship to nearby structures like nerves and blood vessels, and whether it has spread within the bone or to surrounding soft tissues. * **Computed Tomography (CT) scan:** A CT scan uses X-rays from different angles to create cross-sectional images. It's often used to check if the cancer has spread to the lungs, which is a common site for Ewing sarcoma to spread (metastasis). * **Positron Emission Tomography (PET) scan:** A PET scan involves injecting a small amount of radioactive sugar into the body. Cancer cells tend to absorb more sugar than normal cells, making them show up brightly on the scan. This test helps identify areas where the cancer may have spread throughout the body. * **Bone scan:** This test uses a small amount of radioactive material injected into a vein. It travels to bones and highlights areas of abnormal bone activity, which can indicate cancer spread to other bones. **Biopsy:** A biopsy is the only way to confirm a diagnosis of Ewing sarcoma. During a biopsy, a small piece of tissue is removed from the suspicious area. This sample is then sent to a pathologist, a doctor who specializes in examining tissues and cells, to be studied under a microscope. * **Needle biopsy:** This is often performed by inserting a thin needle through the skin into the tumor to extract tissue. It can be guided by imaging techniques like CT or ultrasound. * **Surgical biopsy (open biopsy):** In some cases, a surgeon may need to make an incision to remove a larger piece of the tumor. The pathologist will look for characteristic features of Ewing sarcoma cells. Specialized tests, such as immunohistochemistry and genetic testing (looking for the EWSR1-FLI1 fusion gene), are also performed on the biopsy sample to confirm the diagnosis and distinguish Ewing sarcoma from other types of cancer or non-cancerous conditions. **Bone Marrow Aspiration and Biopsy:** Because Ewing sarcoma can spread to the bone marrow, doctors often perform a bone marrow aspiration and biopsy. This involves taking a small sample of liquid bone marrow and a tiny piece of bone from inside a bone, usually the hip bone, to check for cancer cells.

Treatment Options for Ewing Sarcoma

Once Ewing sarcoma is diagnosed, treatment typically involves a combination of therapies tailored to the individual and the stage of the cancer. Common approaches include chemotherapy, which uses drugs to kill cancer cells, and local treatments like surgery to remove the tumor or radiation therapy to destroy cancer cells in a specific area.

Treatment for Ewing sarcoma is usually aggressive and multidisciplinary, meaning it involves a team of specialists including oncologists, surgeons, radiation oncologists, and pathologists. The goal is to eliminate the cancer and prevent its recurrence. **Chemotherapy:** This is almost always the first treatment given for Ewing sarcoma. Chemotherapy drugs are administered, usually intravenously, to kill cancer cells throughout the body. It is often given before surgery (neoadjuvant chemotherapy) to shrink the tumor, and after surgery (adjuvant chemotherapy) to kill any remaining cancer cells. **Surgery:** If possible, surgery is performed to completely remove the tumor. The extent of surgery depends on the tumor's location and size. Surgeons aim to remove the entire tumor with a margin of healthy tissue around it. In some cases, limb-sparing surgery can be performed to remove the cancerous bone while preserving the limb, often replacing the bone with a prosthesis or bone graft. **Radiation Therapy:** Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or stop them from growing. It may be used if the tumor cannot be completely removed by surgery, or to treat areas where the cancer has spread. It can also be used to shrink tumors before surgery or to relieve pain.

Recovery and Outlook for Ewing Sarcoma

The outlook for individuals with Ewing sarcoma has improved significantly due to advances in treatment. Recovery involves ongoing medical care, including regular follow-up appointments and imaging tests, to monitor for any recurrence of the cancer or long-term side effects of treatment. The prognosis depends on factors like the tumor's size, location, and whether it has spread at the time of diagnosis.

Recovery from Ewing sarcoma treatment is a long process that requires close medical supervision. After initial treatment, patients enter a phase of surveillance, with regular check-ups, blood tests, and imaging scans (like X-rays, MRI, or CT scans) to detect any signs of the cancer returning (recurrence) as early as possible. The outlook for Ewing sarcoma varies greatly among individuals. Factors that generally influence the prognosis include whether the cancer has spread (metastasized) to other parts of the body at the time of diagnosis, the size of the tumor, and its location. Cancers that are localized (have not spread) generally have a better prognosis. Long-term follow-up care is essential not only to monitor for recurrence but also to manage potential late effects of treatment. Chemotherapy and radiation therapy can sometimes cause side effects that appear months or years after treatment, such as heart problems, kidney issues, or the development of secondary cancers. A healthcare team will help manage these potential issues.

When to See a Doctor for Suspected Ewing Sarcoma

You should see a doctor if you or your child experience persistent or worsening bone pain, especially if it doesn't improve with rest or over-the-counter pain relievers. Any unexplained swelling or a noticeable lump on a bone or in soft tissue, particularly if accompanied by fever, fatigue, or unexplained weight loss, warrants prompt medical evaluation.

It is important to remember that most bone pain and lumps are not caused by cancer. However, because early diagnosis of Ewing sarcoma is so important for effective treatment, it is crucial to have any concerning symptoms checked by a healthcare professional. Pay attention to symptoms that are unusual, persistent, or getting worse. For example, if bone pain wakes you up at night, or if a lump grows quickly, these are reasons to seek medical advice. Do not delay seeing a doctor if you have these signs. Your doctor can evaluate your symptoms, perform an initial physical exam, and decide if further tests, such as X-rays or blood tests, are needed. They can then refer you to a specialist, such as an orthopedic oncologist, if Ewing sarcoma or another serious condition is suspected.

Frequently asked questions

Is Ewing sarcoma hereditary?

No, Ewing sarcoma is generally not considered an inherited condition. It arises from genetic changes that occur spontaneously in cells during a person's lifetime, rather than being passed down through families.

What is the first test typically done to diagnose Ewing sarcoma?

The first test often performed when Ewing sarcoma is suspected is an X-ray of the affected area. This imaging test can reveal abnormalities in the bone structure that might suggest the presence of a tumor.

How long does it take to get a diagnosis of Ewing sarcoma?

The time it takes to get a definitive diagnosis can vary. It involves multiple steps, including initial doctor visits, imaging tests, and a biopsy with specialized lab analysis. While doctors aim for efficiency, the complexity means it can take several days to a few weeks.

Can Ewing sarcoma be misdiagnosed?

Yes, Ewing sarcoma can sometimes be misdiagnosed initially because its symptoms, such as pain and swelling, are common to many less serious conditions like sports injuries or infections. A definitive diagnosis requires a biopsy and specialized testing.

What specialists are involved in diagnosing Ewing sarcoma?

Diagnosing Ewing sarcoma typically involves a team of specialists. This may include a primary care doctor, an orthopedic oncologist (bone cancer specialist), a radiologist (interprets imaging scans), and a pathologist (examines tissue samples).

Is Ewing sarcoma curable?

Ewing sarcoma is potentially curable, especially when diagnosed early and treated aggressively. Advances in chemotherapy, surgery, and radiation therapy have significantly improved survival rates, particularly for localized disease. However, the outlook depends on individual factors.

Sources

• MedlinePlus — How Ewing Sarcoma Is Diagnosed
• Mayo Clinic — How Ewing Sarcoma Is Diagnosed
• Cochrane Library — How Ewing Sarcoma Is Diagnosed