Ewing Sarcoma Causes and Risk Factors

Ewing sarcoma is a rare type of cancer that primarily affects bones or, less commonly, soft tissues. It typically occurs in children and young adults. The exact causes are not fully understood, but it develops due to a specific genetic change in cells that happens after birth and is not inherited. Risk factors include age and, in some cases, ethnicity.

What is Ewing Sarcoma?

Ewing sarcoma is a rare and aggressive type of cancer that most often starts in the bones, but can also begin in the soft tissues surrounding bones. It is part of a group of cancers called Ewing sarcoma family of tumors (ESFT). This cancer primarily affects children, adolescents, and young adults, making it the second most common bone cancer in these age groups.

This cancer can develop in any bone, but it is most commonly found in the long bones of the arms and legs, the pelvis, ribs, or spine. Less frequently, it can arise in soft tissues like muscle, fat, or fibrous tissue. The cells of Ewing sarcoma grow rapidly and can spread to other parts of the body, such as the lungs, bone marrow, or other bones. Ewing sarcoma is considered a "small, round, blue cell tumor" based on how its cells appear under a microscope. Its rarity means that many people may not have heard of it before receiving a diagnosis. Understanding its nature is the first step in managing the condition effectively. While it can be a serious disease, advancements in treatment have significantly improved outcomes for many patients. Early detection and a comprehensive treatment plan are crucial for managing Ewing sarcoma.

Symptoms

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 symptoms can be vague and are often mistaken for less serious conditions, making diagnosis challenging.

The most common symptom is persistent pain in the area of the tumor. This pain may worsen over time, especially at night or with activity. It might be a dull ache or a sharp, intense pain. Swelling or a noticeable lump may also develop in the affected area, which can feel warm to the touch. If the tumor is in a leg bone, it might cause a limp. If the tumor is located near a joint, it could limit movement in that joint. For tumors in the spine, symptoms might include back pain, weakness, numbness, or even paralysis if the tumor presses on nerves. These neurological symptoms require immediate medical attention. Beyond localized symptoms, some people with Ewing sarcoma may experience systemic (body-wide) symptoms. These can include a low-grade fever that doesn't go away, feeling very tired (fatigue), or losing weight without trying. Because these symptoms are common to many other conditions, it's important to see a doctor for a proper evaluation if they persist.

Causes & risk factors

Ewing sarcoma develops due to a specific genetic change within cells, usually involving a rearrangement between the EWSR1 gene and another gene, most often FLI1. This change is not inherited from parents but happens randomly after birth. The primary risk factors include being a child or young adult, and it is more common in certain ethnic groups.

The underlying cause of Ewing sarcoma is a chromosomal translocation, which is a type of genetic change where parts of two different chromosomes break off and swap places. In most cases of Ewing sarcoma, a piece of chromosome 11 swaps with a piece of chromosome 22. This creates a new, abnormal gene called a fusion gene, typically EWSR1-FLI1. This fusion gene then produces an abnormal protein that can lead to uncontrolled cell growth and the development of cancer. It is important to understand that this genetic change is not passed down through families (it is not a germline mutation). Instead, it occurs spontaneously in a cell during a person's lifetime. This means that having a family member with Ewing sarcoma does not significantly increase your risk of developing it. The main risk factor for Ewing sarcoma is age. It is most commonly diagnosed in children, teenagers, and young adults, typically between the ages of 10 and 20. It is rare in very young children and adults over 30. Another known risk factor is ethnicity; Ewing sarcoma is more common in people of Caucasian descent and less common in individuals of African American or Asian descent. Beyond these, no clear environmental or lifestyle risk factors have been identified.

How it's diagnosed

Diagnosing Ewing sarcoma typically involves a combination of imaging tests and a biopsy. Doctors use X-rays, MRI, and CT scans to locate the tumor and assess its size and spread. A biopsy, which involves taking a tissue sample for microscopic examination, is essential to confirm the diagnosis and identify the specific genetic changes characteristic of Ewing sarcoma.

The diagnostic process usually begins when a person reports persistent pain or swelling. A doctor will first perform a physical exam and ask about medical history. If Ewing sarcoma is suspected, imaging tests are the next step. An X-ray is often the first imaging test, which can show bone abnormalities. Magnetic resonance imaging (MRI) provides detailed images of the tumor and surrounding soft tissues, while computed tomography (CT) scans can help determine if the cancer has spread to other parts of the body, such as the lungs. To confirm the diagnosis, a biopsy is crucial. During a biopsy, a small sample of the tumor tissue is removed, either with a needle (needle biopsy) or through a surgical incision (open biopsy). This tissue sample is then examined by a pathologist under a microscope. The pathologist looks for the characteristic appearance of Ewing sarcoma cells and performs specialized tests, including genetic tests, to identify the specific EWSR1 fusion gene, which confirms the diagnosis. Further tests may include a bone scan to check for cancer in other bones, and a bone marrow biopsy to see if the cancer has spread to the bone marrow. Blood tests are also performed to assess overall health and organ function. All these tests help doctors determine the extent of the cancer (staging) and plan the most effective treatment.

Treatment options

Treatment for Ewing sarcoma is aggressive and typically involves a combination of chemotherapy, surgery, and radiation therapy. The specific approach depends on the tumor's location, size, and whether it has spread. The goal is to eliminate the cancer cells, remove the tumor, and prevent recurrence, often requiring a multidisciplinary team of specialists.

Chemotherapy is usually the first step in treatment. It involves using powerful drugs to kill cancer cells throughout the body. Chemotherapy is given before surgery or radiation (neoadjuvant chemotherapy) to shrink the tumor, making it easier to remove, and after surgery or radiation (adjuvant chemotherapy) to kill any remaining cancer cells and reduce the risk of the cancer returning. It is typically given in cycles over several months. Surgery is often performed to remove the tumor. The type of surgery depends on the tumor's location. For tumors in the limbs, limb-sparing surgery is often possible, where the tumor is removed while preserving the limb. In some cases, if the tumor is large or has damaged the bone extensively, amputation may be necessary. For tumors in the pelvis or spine, surgery can be more complex and may involve reconstruction. Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or keep them from growing. It may be used after surgery to destroy any cancer cells that could not be removed, or as the primary treatment if surgery is not possible due due to the tumor's location or size. Proton therapy, a type of radiation, may also be used to deliver radiation more precisely to the tumor while sparing surrounding healthy tissues. The treatment plan is highly individualized and developed by a team of oncologists, surgeons, radiation oncologists, and other specialists.

Recovery & outlook

The recovery and outlook for individuals with Ewing sarcoma have significantly improved due to advances in treatment. The prognosis depends on several factors, including the tumor's size and location, whether it has spread, and how well it responds to treatment. Long-term follow-up care is essential to monitor for recurrence and manage any late effects of treatment.

Recovery from Ewing sarcoma treatment can be a long and challenging process. Patients often experience side effects from chemotherapy and radiation, such as fatigue, nausea, hair loss, and a weakened immune system. Physical therapy and rehabilitation are often necessary after surgery to regain strength and mobility, especially after limb-sparing procedures. Emotional and psychological support is also crucial for patients and their families throughout this journey. The outlook for Ewing sarcoma varies greatly. For localized disease (cancer that has not spread beyond the original site), the survival rates are generally higher. If the cancer has spread (metastasized) to other parts of the body, particularly the lungs or bone marrow, the prognosis can be more challenging. However, even with metastatic disease, intensive treatment can lead to long-term survival for some individuals. After completing initial treatment, regular follow-up appointments are vital. These typically include physical exams, imaging scans (like X-rays, MRI, CT), and blood tests to check for any signs of cancer recurrence. Long-term monitoring also helps to identify and manage any late effects of treatment, such as heart problems, kidney issues, or secondary cancers, which can sometimes develop years after therapy. Ongoing research continues to improve treatment strategies and outcomes for Ewing sarcoma patients.

When to see a doctor

You should see a doctor if you or your child experience persistent or worsening bone pain, especially if it's worse at night or with activity, or if there's unexplained swelling or a lump. Other concerning symptoms include an unexplained fever, fatigue, or weight loss. While these symptoms can be caused by many conditions, it's important to get them checked to rule out serious issues like Ewing sarcoma.

Do not delay seeking medical attention if you notice any of the key symptoms. Persistent pain that does not improve with rest or over-the-counter pain relievers is a red flag. This is especially true if the pain is localized to a specific bone or joint and is accompanied by swelling or a palpable mass. Any new lump or swelling that appears without a clear injury should also be evaluated promptly. If the pain is severe enough to interfere with daily activities or sleep, or if it is accompanied by systemic symptoms such as unexplained fever, night sweats, significant fatigue, or unintentional weight loss, it warrants an urgent visit to a healthcare provider. These general symptoms, when combined with localized pain, can sometimes indicate a more serious underlying condition. While it's important to remember that most bone pain or lumps are not cancer, early diagnosis of Ewing sarcoma significantly improves treatment outcomes. Your doctor can perform an examination and order appropriate tests, such as X-rays or blood work, to determine the cause of your symptoms and provide an accurate diagnosis.

Frequently asked questions

Is Ewing sarcoma hereditary?

No, Ewing sarcoma is generally not considered hereditary. It is caused by a genetic change (a chromosomal translocation) that occurs randomly in a cell after birth, rather than being inherited from a parent. This means having a family member with Ewing sarcoma does not increase your risk.

What age group is most affected by Ewing sarcoma?

Ewing sarcoma primarily affects children, adolescents, and young adults. It is most commonly diagnosed between the ages of 10 and 20. It is rare in very young children and in adults over the age of 30.

Are there any known environmental causes for Ewing sarcoma?

Currently, there are no known environmental or lifestyle factors that have been definitively linked to causing Ewing sarcoma. The cancer arises from a specific genetic change within cells that occurs spontaneously, not due to external exposures.

Can Ewing sarcoma be prevented?

Because the exact causes of the genetic changes leading to Ewing sarcoma are not fully understood and are not linked to preventable environmental or lifestyle factors, there are no known ways to prevent this type of cancer.

What are the first signs of Ewing sarcoma?

The first signs of Ewing sarcoma often include persistent or worsening pain in a bone or soft tissue, sometimes accompanied by swelling or a noticeable lump in the affected area. Other early signs can include unexplained fever, fatigue, or weight loss.

Is Ewing sarcoma a common cancer?

No, Ewing sarcoma is a rare type of cancer. It accounts for a very small percentage of all cancers, though it is the second most common primary bone cancer in children and young adults.

Sources

• MedlinePlus — Ewing Sarcoma Causes and Risk Factors
• Mayo Clinic — Ewing Sarcoma Causes and Risk Factors
• Cochrane Library — Ewing Sarcoma Causes and Risk Factors