Is GCT Cancerous?

Medically Reviewed on 1/25/2023

Woman with a tumor speaking to doctor
Giant cell tumors (GCTs) are benign or noncancerous. However, there is a small risk of GCTs transforming into cancerous tumors.

Giant cell tumors (GCTs) are benign (noncancerous) tumors that most commonly occur in the bones of the arms and legs. These tumors are also called osteoblastoma or giant cell reparative granuloma.

  • GCTs can occur in the spine, pelvis, and other bones. Giant cell tumors typically affect young and middle-aged adults and are more common in women than in men.
  • They can grow quite large and may cause pain, swelling, and deformity in the affected bone. Although giant cell tumors are benign, they can cause problems if they press on nearby structures or grow and weaken the bone to the point of fracture.
  • GCTs are not cancerous. They can cause problems if they grow or spread to other parts of the body. In some cases, GCTs may recur after treatment, and there is a small risk of GCTs transforming into cancerous tumors.
  • Treatment for GCTs usually involves surgically removing the tumor. In some cases, additional treatment with medications or radiation could be necessary to prevent the tumor from returning. People with GCTs need regular follow-up care to monitor for any recurrence or transformation of the tumor.

What are the signs and symptoms of GCT?

Giant cell tumors (GCTs) are a type of bone tumor. GCTs are characterized by large, multinucleated cells called giant cells. The signs and symptoms of GCTs may vary depending on the location and size of the tumor.

  • Pain: GCTs can cause pain, especially when the tumor is near a joint. The pain could be constant or intermittent and worsen with activity.
  • Swelling: The tumor may cause swelling in the affected area, which could be noticeable if the tumor is large or located near the surface of the skin. This could be due to the presence of fluid within the tumor.
  • Tenderness: The area around the tumor could be tender to the touch.
  • Fractures: GCTs can weaken the bone, leading to a higher risk of fractures. This is more common if the tumor is in a weight-bearing bone, such as the femur or tibia.
  • Numbness or weakness: If the tumor is pressing on a nerve, it may cause numbness or weakness in the affected area.
  • Limited movement: The tumor may cause stiffness or limited movement in the affected joint if it is located near a joint. GCTs can weaken the affected bone, leading to difficulty with weight bearing or mobility.
  • Mass or lump: In some cases, the tumor could be visible as a mass or lump under the skin.

These symptoms could be caused by other conditions. If you are experiencing any of these symptoms, see a doctor for a proper evaluation.


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What are the causes of giant cell tumors?

Giant cell tumors (GCTs) arise from cells called osteoclast precursors. These cells break down and resorb bone tissue during normal bone remodeling. The exact cause of GCTs is not fully understood, but they are thought to be related to abnormal proliferation and differentiation of osteoclast precursors.

Some studies suggest that genetic factors may play a role in the development of GCTs. Evidence suggests that certain environmental factors, such as radiation exposure and infection, may increase the risk of developing GCTs.

Possible causes and risk factors of giant cell tumors

  • Genetic factors: Some studies have suggested that genetic factors may play a role in developing GCTs. Some people may have a genetic predisposition to developing GCTs, meaning they have a higher risk of developing these tumors due to inherited genetic factors. Mutations in the C-FOS gene have been identified in some cases of GCTs.
  • Environmental factors: Exposure to certain environmental toxins.
  • Trauma: Previous injury to the bone may increase the risk of developing GCTs.
  • Hormonal imbalances: Some studies suggest that hormonal imbalances, such as high estrogen levels, could be associated with the development of GCTs.
  • Infection: Tuberculosis or fungal infections.
  • Inflammation: Chronic inflammation in the bone, such as that caused by osteomyelitis (an infection of the bone).
  • Underlying medical conditions: Paget's disease (causes abnormal bone growth), multiple myeloma (affects the bone marrow) or other bone disorders.
  • Age: GCTs most commonly occur in people aged between 20 and 40 years.
  • Gender: GCTs are more common in women than in men.
  • Family history: Some evidence suggests that a family history of GCTs may increase a person's risk of developing the condition.
  • Previous radiation therapy: People who have received radiation therapy for other types of cancer could be at an increased risk for developing GCTs.
  • Previous surgery: Some studies suggest an increased risk of GCT in people who have had surgery on the affected bone.
  • Previous bone infection: People who have had a bone infection could be at increased risk.
  • Osteoporosis: Weakens the bones.

The exact cause of GCTs is not fully understood; the majority of GCTs occur spontaneously and are not associated with any known risk factors. Further research is needed to fully understand the causes of GCTs and develop more effective treatments.

What are the treatment options for giant cell tumors?

Treatment options for giant cell tumors (GCT) depend on various factors, including the size and location of the tumor, the person’s age and overall health and whether the tumor has spread to other parts of the body.


  • The most common treatment for GCTs is usually the first line of treatment. The goal of surgery is to remove the entire tumor and a small margin of healthy tissue around it.
  • The type of surgery that is performed will depend on the location and size of the tumor. For small tumors that are easily accessible, a simple excision or curettage (scraping) could be sufficient.
  • For larger tumors or tumors that are in a difficult-to-reach area, a more extensive surgical procedure may be needed.

Types of surgery performed for GCT

  • Curettage and bone grafting: This involves removing the tumor with a spoon-shaped instrument called a curette and filling the resulting cavity with bone graft material. This procedure could be an option for small or superficial tumors.
  • Wide excision: Involves removing the tumor and a wider margin of surrounding tissue to ensure that all tumor cells have been removed. This could be used for larger or more deeply seated tumors.
  • Amputation: Used when the tumor is large or cannot be removed without causing significant damage to the surrounding bone or tissues.

After surgery, some patients may need additional treatment, such as radiation or chemotherapy, to reduce the risk of the tumor returning. Physical therapy could be recommended to help restore strength and function to the affected limb.


  • High-energy radiation destroys abnormal cells. It could be used in combination with surgery to reduce the risk of recurrence or as a standalone treatment for small, slow-growing GCTs that are not easily accessible through surgery.


  • Drugs kill abnormal cells. It is generally not used as a first-line treatment for GCTs but may be considered in certain cases, such as when the tumor is too large to be removed surgically or the person is not suitable for surgery.

Monoclonal antibodies

  • Blocks the action of a protein that promotes the formation of bone-damaging cells called osteoclasts. This could be used in combination with surgery or radiation therapy to help control the growth of GCTs.


  • The use of extreme cold to destroy abnormal cells. It is sometimes used to treat small GCTs that are not easily accessible through surgery.


  • In some cases, the “wait and see” approach is recommended if the GCT is small, slow growing, and not causing any symptoms. The tumor will be monitored with regular imaging tests.
  • Discuss all treatment options with a doctor and consider each option's potential risks and benefits. In some cases, a combination of different treatment approaches could be recommended.
  • GCTs can recur after treatment; long-term follow-up with a healthcare provider is usually recommended.

What is the outcome of patients with giant cell tumors?

  • The outcome of giant cell tumors (GCT) is generally good because these tumors are not aggressive and can often be treated successfully with surgery. In most cases, complete removal of the tumor is possible and leads to a good outcome.
  • The long-term survival rate for people with GCTs is generally very good, with most experiencing no tumor recurrence after successful surgery. In rare cases, GCTs may recur or progress to a more aggressive form called giant cell sarcoma, which can be more difficult to treat.
  • There is a high rate of successful treatment and long-term remission with GCTs. People with GCTs need to be monitored closely using regular imaging studies and physical exams for any recurrence or progression of the tumor.
Medically Reviewed on 1/25/2023
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