Osteosarcoma In Children: Types, Causes, Symptoms, And Treatment

Although rare, osteosarcoma (bone cancer) in children accounts for around two percent of cancer cases and is the most common malignant tumor in bone tissue (bone cancer). According to the American Cancer Society, it affects around 1000 people every year, while half of the cases are seen in children and adolescents (1).

Osteosarcoma can gradually spread from the bones to surrounding lymph nodes, tissues, and other body parts. The cancer cells are similar to osteoblasts (cells that form bone cells from bone tissues) and can form the bones, its matrix (osteoid), or both. But, bone tissues formed in osteosarcoma are weaker than in normal bones (2).

Read on to know about the cause, risk factors, symptoms, complications, diagnosis, and treatment for osteosarcoma in children.

Risk Factors And Causes Of Osteosarcoma In Children

The exact cause of osteosarcoma and other bone cancers in children is unknown. Mutations in the DNA could be a reason, as in many other types of cancers. However, most children do not inherit these gene mutations from their parents, and they often occur by chance.

The following conditions or factors may increase the risk of developing osteosarcoma in some children (3) (4).

• Rare genetic cancer syndromes such as hereditary retinoblastoma (eye cancer originating from the retina) with RB1 gene mutation and Li-Fraumeni syndrome (hereditary cancer predisposition syndrome) with TP53 gene mutation.

• Rothmund-Thomson syndrome, which is caused by REQL4 gene mutations and results in skin and skeletal problems and short stature.

• Rare inherited conditions such as Bloom syndrome (BS), which causes sun sensitivity, red rash on the nose and cheeks, and short stature; Werner syndrome (progeria), which causes premature aging; and Diamond-Blackfan anemia, which is a bone marrow dysfunction that affects the production of red blood cells.

• Radiation therapy

• Chemotherapy

• Male gender and tall stature

• Certain bone diseases such as fibrous dysplasia and Paget’s disease of bone

• Race/ethnicity: African-Americans and Hispanics are slightly more prone to it than whites.

Although the exact cause of osteosarcoma is unknown, these risk factors are believed to cause genetic changes that stimulate the genes for cell growth (oncogenes) and suppress the genes controlling cell growth (tumor suppressor genes), which could be a reason for developing cancers. Further, children with inherited conditions may have certain mutant genes in their cells that increase the risk of developing several types of cancers.

Signs And Symptoms Of Osteosarcoma In Children

The symptoms and signs of bone cancer may vary in each child depending on their age, health status, and tumor size and location. The bones in the limbs (arms and legs) are commonly affected.

These are the bones around the knee, such as the lower part of the femur (thigh bone) or upper part of the tibia (shinbone), and upper arm bone near the shoulder (humerus). However, osteosarcoma can affect any bone, including the pelvis (hips), jaw, or shoulder (2).

The common symptoms of osteosarcoma may include (5) (6)

• Tenderness or stiffness at the site of the tumor.
• Joint pain that worsens over time and interferes with sleep.
• A mass, lump, or swelling seen around the affected bone.
• Fractures without any injury causing it.
• Bone pain at the tumor site that progressively worsens and radiates outward.
• Decline in motor skills.
• Back pain and bladder or bowel incontinence if the tumor is in the pelvis or near the spine.
• Anemia
• Weight loss
• Fatigue

If these symptoms are not present, doctors may look for other medical conditions. Some children may have uncommon symptoms such as pain radiating to other parts, such as a tumor near the spine causing pain in the arms.

Diagnosis Of Osteosarcoma

Doctors may order imaging tests and other tests, such as a biopsy, if the clinical features and physical examination findings suggest the presence of osteosarcoma or other bone diseases. These tests help rule out other conditions and confirm the size, location, and type of bone cancer, if present. A biopsy alone can confirm the type of cancer, so it is ordered after identifying cancerous tissue on the imaging tests.

In addition to the initial blood tests and lab tests, the doctor may also order (7)

• X-rays of the suspected area where the lump, pain, or swelling is present around the bone, which may reveal certain features of osteosarcoma. However, other imaging tests are required to confirm the diagnosis.

• CT scans (computed tomography scan), which present images of the body in various angles using X-rays. The tumor’s location and size can be defined from a CT scan, and often, special dyes are injected to enhance visibility. Metastatic tumors can also be identified through CT scans of other parts of the body.

• MRI scans (magnetic resonance imaging scans) that use magnetic fields to create images of body tissues. They may help to identify the tumor, its size, and the site where it started as well as the tumor margins and how much it spread, which is useful for treatment. Clearer images can be obtained using special dyes.

• PET scans (positron emission tomography scan) or PET-CT scans, which include CT scans and injectable radioactive tracers. Radioactive sugar is injected into the body, which is absorbed by the tumor cells since they tend to use more energy, causing the tumors to become visible on the scanner. This is a useful method to find distant metastatic tumors.

• Bone scans, which use a radioactive tracer that is injected into the veins and mostly collects in the areas of the bone with injury or cancer than healthy bone tissue. This may help identify the spread of osteosarcoma in the bone where it started and in other

• Biopsies, which are ordered to identify the type of cancer, which is necessary for planning treatments, by analyzing its histologic features after confirming cancer through imaging tests. Orthopedic oncologists (specialists in bone tumors) perform the core needle biopsy to collect samples.

After the diagnostic tests are completed, pediatric oncologists explain the cancer’s location, type, size, and stage, as well as the treatment strategies and possible prognosis, including the survival rates, to the parents or guardians of the child. 

Types Of Osteosarcoma

Osteosarcoma can be classified into two types: primary osteosarcomas and secondary osteosarcomas. Primary osteosarcomas originate in the bone cells and are not linked to any other diseases or cancers.

According to the classification by the World Health Organization, the subtypes of primary osteosarcoma are (8)

• Surface osteosarcoma, which develops on the bone
• Intramedullary/central osteosarcoma, which originates in the medullary cavity of the bone.

Secondary osteosarcoma is a malignancy that develops at least two months after primary cancer treatment and is linked to conditions acquired during primary cancer treatment and genetic factors (9).

Osteosarcomas are graded as follows depending on the growth rate.

• High-grade: It refers to a fast-growing cancer with various subtypes and is the most common type of osteosarcoma in children.

• Low-grade: It is a slow-growing cancer.

After the diagnosis, doctors further classify osteosarcoma into two groups, localized and metastatic. Then, osteosarcoma is further categorized into stages using the Musculoskeletal Tumor Society (MSTS) system or Enneking system based on the grade, metastasis (spread to distant locations in the body), and extent of the primary tumor. The treatment plans and prognosis may vary for each stage.

Classification can also be done using the American Joint Commission on Cancer (AJCC) TNM system. The classification of tumors can be confusing, so you could ask your healthcare provider to explain the stage, grade, or type of osteosarcoma present (10). 

Treatment For Osteosarcoma

The following treatment strategies can be used based on the stage, expected prognosis, child’s health status, and age (11).

• Surgery: Limb-sparing surgery or limb-salvage surgery can be performed to save an arm or leg. Surgery may also be done where amputation of limbs is required or to remove tumor tissues from any part of the body.

• Chemotherapy: Strong medicines are given to destroy the cancer cells. This is often administered before surgery and sometimes after surgery, depending on the tumor and individual factors. Chemotherapeutic drugs are usually given in cycles with gaps.

• Targeted therapy: This is a form of chemotherapy where the drugs precisely target the cancer cells. This method may help limit normal cell (healthy cell) damage while killing the cancer cells. 

• Radiotherapy: High-energy X-rays or other kinds of radiation are delivered to the cancer tissues to destroy tumor cells or arrest their growth. Radiotherapy is often used when surgery cannot remove the tumor completely or to slow down the tumor’s growth.

Children who get immediate treatment have the best prognosis. Sometimes, doctors may suggest new treatments available on clinical trials with improved outcomes and fewer side effects. Most children require follow-up visits during and after treatments to assess their improvement and manage the side effects.

Possible Complications Of Osteosarcoma

Children may experience complications from osteosarcoma and side effects from the treatments, which may include (12)

• Growth and developmental issues.
• Bleeding or infection after surgery.
• Chemotherapy side effects such as hair loss, diarrhea, bruising, bleeding, infections, nausea, vomiting, tiredness, and mouth sores.
• Radiotherapy side effects such as nausea, diarrhea, hair loss, organ damage, poor bone growth, and secondary cancers (new cancers after radiation).
• Broken or loose grafts or rods after limb-sparing surgery.
• Heart and lung complications after chemo or radiotherapy.
• Physical and emotional issues due to the tumor and its treatments.
• Fertility issues in future.
• Recurrence (return of cancer) or secondary cancers later in life.

Although many cancer treatments have certain side effects, cancers can be life-threatening and can spread locally or metastasize if left untreated. Each child’s risk of side effects and prognosis may vary based on the stage and other individual factors. It is recommended to discuss with your pediatric oncologist to choose the best cancer care for your child.

When To Call A Doctor

Usually, healthcare providers will inform you about the problems to observe and when to seek medical care after returning home. Ensure you have the phone numbers of the doctor’s office and alternative contacts for holidays.

If you notice any of the following, inform your healthcare provider immediately (12).

• New symptoms and signs
• Worsening of symptoms or no change in symptoms such as vomiting even after taking the prescribed antiemetic medications
• Fever and chills
• Cough and shortness of breath or other breathing troubles
• Issues with eating and drinking
• Severe diarrhea

Prognosis Of Osteosarcoma In Children

The five-year survival rate for children up to 14 years with osteosarcoma is 68%. On the other hand, 15- to 19-year-olds have a five-year survival rate of 67%. If a child is treated before cancer spreads to other areas, the survival rate increases to 74%. However, it can reduce to 66% if cancer spreads to the organs and lymph nodes near the bones (13).

The five-year survival rate offers information about the percent of children who live at least five years after their cancer diagnosis. The survival rates may vary depending on the type, treatment, and spread of cancer.

It is important to understand that these statistics are estimates based on the annual data of children and teens with the same cancer in the US. These estimates do not involve the results of better diagnosis and treatments. Thus, it is recommended to discuss the best outcomes with your doctor to know the treatments rather than make decisions based on the survival rates.

Tips To Help Children With Osteosarcoma

Ongoing care and regular follow-up are required for a child with osteosarcoma. In addition to medical care, children require constant encouragement and support from parents to cope with the emotional and physical changes due to cancer.

The following tips can help a child cope with osteosarcoma.

• Never skip follow-up visits. The side effects of cancer treatment and signs of recurrence are evaluated and managed during the follow-ups. Several imaging tests and other tests are performed for this purpose.

• Consult a dietician. Children with eating or drinking problems due to cancer may need a dietician’s help. They may help establish a diet to prevent weight loss and nutrition deficiencies in your child.

• Get emotional support. Most children and families require the help of psychologists, therapists, and support groups to overcome the emotional issues caused by the disease. These groups can help the child stay positive during the treatment period.

• Encourage exercise and rest. Children may constantly feel tired due to treatments. To overcome this, parents could encourage them to try some simple exercises suggested by healthcare professionals.

• Inform the teachers and school administration about the condition. Teachers and peers who are aware of the situation can encourage the child to stay positive and help with academic lessons at home or after treatment.

• Consider physical and occupational therapies. These are required after surgery or other treatments to regain movement and muscle strength.

Usually, pediatric oncologists refer the child to specialists in pediatric cancer nutrition and occupational therapy after or during the cancer care based on the need. You may also ask your child’s doctor about financial aid programs that support cancer treatment and follow-ups for children.

References

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Reviewer

Dr. Arva M BhavnagarwalaMBBS, DNB

 

Dr. Arva Bhavnagarwala did her post-graduation from Masina Hospital in Mumbai and worked at Jaslok Hospital and Research Center as a Clinical Associate. With seven years of experience, she currently practices pediatrics at her private clinic in South Mumbai and is attached to Masina Hospital as a consultant pediatrician.

Read full bio of Dr. Arva M Bhavnagarwala