Osteosarcoma

Childhood Cancer Name:

Bone tumor – Osteosarcoma; Osteosarcoma (OS); Osteogenic sarcoma (OGS); Aggressive Malignant Neoplasm of Mesenchymal origin; Malignant Osteoid; Conventional Osteosarcoma.

Explanation:

Osteosarcoma is the most common type of cancer that arises in bones, and typically found at the end of long bones. Most people diagnosed with osteosarcoma are between the ages of 10 to 25.

Characteristics:

Osteosarcoma is most often seen in teenage boys. Teens diagnosed with osteosarcoma tend to be tall for their age, suggesting that rapid bone growth may lead to the disease. Osteosarcoma is a type of cancer that produces immature bones. It is the most common histological form of malignancy of the bone, called Conventional Osteosarcoma when it affects teenagers or young adults.

Biology:

In most cases, it is found in the bones around the knee.  Located in the growing ends of the bone (metaphysis).

Causes: Although not very well defined, the cause of osteosarcoma is considered a combination of genetic changes. Together, they cause immature bone cells to become tumor cells instead of healthy bone. A gene known as RB may be associated with osteosarcoma, which is also the gene responsible for the eye cancer called retinoblastoma.
Some groups of people are more likely to develop osteosarcoma like; teenagers having a growth spurt, osteosarcoma is 50% more common in boys, radiation treatment or its high dose can increase the risk of the disease whereas several research groups are investigating cancer stem cells and their potential to cause tumors.
Most Osteosarcomas are not caused by inherited DNA mutations. They are the result of gene changes acquired during the person’s lifetime and these changes are most often present only in the cancer cells and are not passed on to children.

Main types:

There are two types of osteosarcoma.

• Central tumor, also called a medullary tumor
• Surfacetumor, also called a peripheral tumor

Each type of osteosarcoma has different subtypes. The type and subtype of osteosarcoma is determined by looking at the tumor cells through a microscope.

Subtypes of medullary osteosarcoma include:

• Conventional central osteosarcoma, such as osteoblastic, chondroblastic, fibroblastic, and mixed types
• Telangiectatic osteosarcoma
• Intraosseous well-differentiated or low-grade central osteosarcoma
• Small cell osteosarcoma

 Subtypes of peripheral osteosarcoma include:

• Parosteal well-differentiated or low-grade osteosarcoma, also called juxtacortical osteosarcoma
• Periosteal osteosarcoma that is low grade to intermediate grade
• High-grade surface osteosarcoma

The most common subtype of osteosarcoma is conventional central osteosarcoma. The other subtypes are much less common. They each account for less than 5% of all osteosarcomas.

Grade is the most important factor in treatment decision-making. This is because low-grade tumors only recur in the same area, called locally. High-grade tumors metastasize, or spread, to other parts of the body and can recur anywhere in the body. Most osteosarcoma in children are high grade.

Childhood Cancer Localization:

Osteosarcoma occurs in large bones in the area of bone with the fastest growth rate, most commonly in the:

• Shin (near the Knee)
• Thigh (near the knee)
• Upper Arm (near the shoulder)
  They typically occur at the metadiaphysis of tubular bones in the appendicular skeleton;
• Long Bones: Femur 40%, Tibia 16%, Humerus 15%.
• Less Common Sites(29%): Fibula, innominate bone, mandible (lower jaw), maxilla (jaw bone), vertebrae

Childhood Cancer Noticeable Symptoms:

The first symptom is usually bone pain near a joint, the pain may get worse at night, may be intermittent and of varying intensity. Other symptoms may include a sudden fracture, limitation of motion, Limping, pain when lifting, tenderness, swelling or redness at the site of tumor. Back pain or a loss of bowel or bladder control is also a symptom that can occur if the tumor is in the pelvis or at the base of the spine.

Parents tips:

The pain often considered to be related to muscle soreness or “growing pains”, but it does not go away with rest. The symptoms can also be misdiagnosed as Sports Injury, but if you are concerned about any changes your child experiences, please consult a doctor immediately.

Childhood Cancer Diagnostic Method:

An X-ray is the first diagnostic test. An experienced radiologist would recognize if bone cancer is the likely diagnosis. This is followed by MRI, which helps to rule out the metastases stage or spread of the tumor, a CT scan and a PET scan to detect metastases to other organs, bones, or other parts of the body. A bone scan is being done to rule out distant spread of the disease. A biopsy of the tumor provides a definite diagnosis to determine whether the tumor is malignant or benign.

Childhood Cancer Treatment:

• Chemotherapy – Neo-adjuvant therapy
• Surgery – to remove the tumor.
• Surgery is also required in cases where an amputation or a rotationplasty is performed (limb-sparing surgery). This is followed by an implant surgery or an allograft for replacement of the tissue.
• Radiation Therapy

Late effects of the treatments and follow-up:

Care for children diagnosed with cancer does not end when active treatment has finished. Your child’s health care team will continue to check that the cancer has not come back, manage any side effects, and monitor your child’s overall health. This is called follow-up care. All children and teens treated for cancer, including osteosarcoma, should have life-long follow-up care.

Your child’s follow-up care may include regular physical examinations and medical tests. Doctors want to keep track of your child’s recovery in the months and years ahead.

The main considerations for the long-term health of children and teens who have had osteosarcoma are:

• Recurrence of osteosarcoma (Recurrence of osteosarcoma more than 5 years later is rare. The drugs used to treat osteosarcoma have a small chance, about 1.5%, of causing a blood cancer called leukemia. This is called secondary leukemia).
• Appearance of a new type of cancer (called a secondary cancer)
• Orthopedic complications and other late effects of the cancer treatment.

Cancer rehabilitation may be recommended, and this could mean any of a wide range of services such as physical therapy, family or individual counseling, nutritional planning, and/or educational assistance. The goal of rehabilitation is to help survivors and their families regain control over many aspects of their lives and remain as independent and productive as possible.

References:

• http://www.cancer.net/cancer-types/osteosarcoma-childhood/overview
• https://www.cancer.org/cancer/osteosarcoma.html
• https://radiopaedia.org/articles/osteosarcoma
• http://ozradonc.wikidot.com/pathology:osteosarcoma
• https://medlineplus.gov/ency/article/001650.htm
• http://sarcomahelp.org/osteosarcoma.html#tpm1_1
• https://www.mayoclinic.org/diseases-conditions/osteosarcoma/symptoms-causes/syc-20351052

Specialist Consultation Insights:

Osteosarcoma – recurrent disease with lung metastases after multiple resections.

Last updated February 2026

Snapshot

Age range: young adult (late teens/early 20s)

Cancer type: osteosarcoma

Primary location: lower leg bone (fibula region), with prior limb-sparing surgery

Current situation: multiple relapses over time, including recurrent lung nodules that were surgically removed when feasible

Clinical question: after repeated resections and frequent recurrences, what systemic strategy is most reasonable to reduce recurrence risk and control disease?

How specialists think about this situation

In osteosarcoma, it is important to consider not only where the cancer recurs, but how often and how quickly it returns. When recurrences are frequent and the interval between them is shrinking, observation only is not recommended because microscopic disease may persist even with normal imaging after surgery. Another key factor is whether there is measurable disease on scans. Some treatments and clinical trials are only available when visible tumors are present, while others are designed for patients who have had all known disease surgically removed. This distinction strongly shapes treatment planning.

Treatment paths discussed

Because there is no single standard approach for relapsed osteosarcoma, several options were discussed:

1. Targeted therapy – tyrosine kinase inhibitors (TKIs)
   These treatments aim to slow tumor growth by interfering with cancer signaling pathways. They are typically taken orally and may be continued as long as they are effective and tolerated.
2. Oral and combination chemotherapy
   In some situations, chemotherapy may be combined with other agents designed to make cancer cells more sensitive to treatment. These approaches are often considered on a case-by-case basis.
3. Immune-based or personalized approaches
   Immune therapies, vaccines, or other experimental strategies may be discussed, particularly through clinical trials, where newer approaches are being evaluated.
4. Clinical trials
   Clinical trials are frequently part of the discussion in relapsed osteosarcoma, since they can provide access to experimental treatments not otherwise available.

Why one path may be favoured over another?

Given the pattern of frequent recurrence, the specialist felt that observation alone after surgery would likely carry a high risk of further relapse. As a result, strategies that could provide ongoing disease control or serve as a bridge to a clinical trial were emphasized.

The final decision depends on a holistic consideration of expected benefit, potential side effects, length of treatment, and how each option fits into the patient’s daily life and long-term goals.

Useful questions for parents to ask their child’s care team

• Has all visible disease been removed, or is there measurable disease right now?
• Given the recurrence pattern, is observation alone reasonable?
• What is the main goal of the next treatment: prevention, control, or preparation for a trial?
• Which options are standard treatments and which are experimental?
• How might treatment affect daily activities, school, or work?

About this consultation summary
This summary was created by MyChild’sCancer based on a review of anonymized specialist consultations provided to families seeking additional expert input. The content reflects general medical reasoning discussed by specialists in this case and is intended for educational purposes only. It does not replace medical advice from a child’s treating care team. MyChild’sCancer is a nonprofit organization dedicated to supporting families affected by childhood cancer by providing access to information, expert consultations, and community resources.