Sarcoma bone

Sarcoma Bone

Overview of Human Bones

The human body has 206 bones, and the inside of bones contains a spongy material called bone marrow, which produces blood cells. There are three key types of bone cells:

• Osteoclasts: Remove old bone cells

• Osteoblasts: Create new bone cells

• Osteocytes: Deliver nutrients to the bone

What is Bone Sarcoma?

Bone sarcoma is a type of bone cancer where healthy bone cells grow uncontrollably to form a tumor.

• Benign tumors grow but do not spread.

• Malignant tumors (cancerous) can spread to other areas of the body.

Types of Bone Sarcoma

Different types of bone sarcoma include:

1. Chondrosarcoma: Affects the cartilage; more common in older adults.

2. Chordoma: Starts in the spine.

3. Ewing’s sarcoma: Common in children and young adults.

4. Osteosarcoma: Occurs mainly in children and adolescents.

Rare soft-tissue sarcomas that may originate in bones:

• Undifferentiated Pleomorphic Sarcoma (UPS)

• Fibrosarcoma

Statistics

• The exact incidence of bone sarcoma in India is not well documented.

• In the United States, approximately 3,970 cases are reported annually.

Risk Factors

Several factors can increase the likelihood of developing bone sarcoma:

• Genetic conditions: Syndromes like Retinoblastoma and Li-Fraumeni syndrome.

• Previous radiation therapy: Radiation exposure in the past can lead to sarcoma.

• Chemotherapy: Certain chemotherapy drugs increase the risk of osteosarcoma.

• Bone disorders: Conditions like Paget’s disease and fibrous dysplasia can elevate risk.

Symptoms of Bone Sarcoma

• Pain: The most common symptom. Initially intermittent, but later it becomes persistent.

• Swelling and stiffness: Tumors near joints cause swelling and restricted movement.

• Limping: May occur as the tumor grows.

Diagnosis

• Biopsy: A tissue sample is examined under a microscope to confirm cancer.

• X-ray

• Bone scan

• CT scan

• MRI

• PET-CT

• Blood tests: Includes alkaline phosphatase and lactate dehydrogenase (LDH) tests.

Staging and Grading of Bone Sarcoma

Stages of Bone Sarcoma:

1. Localized: Confined to one area and can be surgically removed.

2. Locally advanced: Has not spread to distant parts but is challenging to remove.

3. Metastatic: Has spread to other organs or tissues.

Grades:

• GX: Grade cannot be determined.

• G1: Well-differentiated tumor cells.

• G2: Moderately differentiated tumor cells.

• G3: Poorly differentiated tumor cells.

Stage Groups:

• Stage IA: Low-grade tumor ≤8 cm, no spread.

• Stage IB: Low-grade tumor >8 cm, no spread.

• Stage IIA: High-grade tumor ≤8 cm, no spread.

• Stage IIB: High-grade tumor >8 cm, no spread.

• Stage III: Multiple high-grade tumors in one area, no distant spread.

• Stage IVA: Spread to lungs.

• Stage IVB: Spread to bones or other organs beyond the lungs.

• Recurrent: Cancer that has returned after treatment.

Treatment Options

1. Surgery

Surgery involves removing the tumor along with some surrounding healthy tissue.

• Limb-sparing surgery: Removes the tumor without amputating the limb. This is possible for 90% of patients.

• Amputation: Performed if limb function cannot be preserved.

2. Chemotherapy

Chemotherapy uses drugs to stop the growth of cancer cells.

• Neoadjuvant chemotherapy: Administered before surgery to shrink the tumor.

• Adjuvant chemotherapy: Given after surgery to destroy any remaining cancer cells.

Side effects: Fatigue, infections, hair loss, nausea, vomiting, loss of appetite, and diarrhea. Most side effects diminish after treatment.

3. Targeted Therapy

For a small subset of sarcomas with NTRK gene mutations, drugs like:

• Larotrectinib (Vitrakvi)

• Entrectinib (Rozlytrek)

These therapies block the growth of specific cancer cells.

4. Immunotherapy

Research is ongoing to explore immunotherapy options for bone sarcoma treatment.

5. Radiation Therapy

Radiation is used if the tumor is inoperable or to reduce the size of the tumor before surgery. It is also used after surgery to eliminate remaining cancer cells.

Follow-Up Care

After treatment, regular follow-up care is essential to:

• Monitor for recurrence

• Manage side effects

• Perform physical exams, blood tests, and imaging tests

Bone sarcoma, though rare, can be effectively treated with surgery, chemotherapy, and radiation if diagnosed early. Long-term follow-up ensures better management and improved outcomes for patients.

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