Osteosarcoma

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Synonyms

Chondro-osteosarcoma, osteochondro-myxosarcoma, osteochondrosarcoma, osteofibrosarcoma, osteoid sarcoma, UICC, osteogenic sarcoma, ,

Overview

Osteosarcoma is a type of bone cancer where cancer cells form in bone tissue, specifically from osteoblasts (cells that make new bone). It’s the most common primary malignant bone tumor, though still relatively rare, accounting for a small percentage of all cancers. Osteosarcoma typically affects the long bones of the arms and legs, particularly near the knee. It’s most common in adolescents and young adults but can occur in older individuals as well. 

Symptoms

Osteosarcoma symptoms primarily involve bone pain and swelling, often accompanied by a noticeable lump, especially near the knee or arm. Pain may initially be intermittent, but it tends to worsen over time, especially at night, and may increase with activity. A broken bone (fracture) after a minor injury can also be a sign, especially if the bone was already weakened by the tumor. 

More detailed explanation of symptoms:
  • Bone pain:
    This is the most common symptom and can be the first indicator of osteosarcoma. The pain may be constant or come and go, and it’s often worse at night or with activity. 

  • Swelling and tenderness:
    Swelling around the affected bone is another common symptom, and it may be accompanied by tenderness to the touch. 

  • Lump or mass:
    A noticeable lump or mass may develop over the affected bone, although this may not be apparent until later in the disease progression. 

  • Fracture:
    Osteosarcoma can weaken bones, making them more susceptible to fractures from minor injuries. 

  • Limping:
    If the tumor is located in a leg or near a joint, it can cause limping due to pain and restricted movement. 

  • Reduced range of motion:
    Difficulty moving the affected joint may occur due to pain, swelling, and the tumor’s impact on the bone and surrounding tissues. 

  • Weight loss and fatigue:
    While not specific to osteosarcoma, these symptoms can sometimes accompany bone cancer. 

Important considerations:
  • Symptoms of osteosarcoma can be similar to those of other, more common conditions like sports injuries or growing pains, especially in children and adolescents.
  • Any persistent bone pain, swelling, or other concerning symptoms should be evaluated by a doctor to rule out osteosarcoma or other potential causes.
  • Early diagnosis and treatment are crucial for improving the chances of a positive outcome with osteosarcoma

Causes

The exact cause of osteosarcoma, a type of bone cancer, is unknown. However, researchers have identified several risk factors and potential contributing factors. These include prior radiation therapy, certain genetic conditions, and rapid bone growth.

Prevention

There are currently no methods to prevent osteosarcoma, as no lifestyle factor is known that increases the risk of osteosarcoma. However, quitting smoking, exercising, eating a healthy diet, and improving your lifestyle, can prevent several cancers.

Diagnosis

Osteosarcoma diagnosis typically involves a combination of imaging tests, biopsy, and potentially other blood tests to confirm the presence and extent of the tumor. A physician will start with a thorough medical history and physical exam, followed by imaging to visualize the tumor, and then a biopsy to confirm the cancerous nature of the cells. 

Steps in Osteosarcoma Diagnosis
  1. 1. Medical History and Physical Exam:
    The doctor will ask about symptoms, previous medical conditions (including radiation treatment), and family history of cancer. They will also examine the affected area for any visible or palpable masses. 

  • 2. Imaging Tests:
    • X-rays: Initial imaging to visualize the bone and identify potential tumors. 
  • MRI: Provides detailed images of soft tissues and bone marrow, helping to further characterize the tumor and assess its extent. 
  • CT scans: Can be used to evaluate the bone and surrounding tissues and assess for metastasis. 
  • Bone scans: Used to detect tumors in other bones. 
  • PET scans: Can be helpful in detecting metastasis. 
  • 3. Biopsy:
    A biopsy is essential for definitive diagnosis. Medical journals note that biopsies must be performed by or under the supervision of an orthopedic oncologist. There are different types of biopsies, including core needle biopsy, fine needle aspiration, and surgical biopsy. 

  • 4. Blood Tests:
    A complete blood count (CBC) may be performed to assess overall health. 

  • 5. Staging:
    After diagnosis, staging tests are performed to determine if the cancer has spread to other parts of the body. 

Key Points:
  • Osteosarcoma is often diagnosed in adolescents and young adults, but can also occur in older adults. 
  • Pain and swelling are common presenting symptoms. 
  • A biopsy is crucial for confirming the diagnosis and guiding treatment. 
  • Imaging tests are used to assess the tumor and its spread. 

Prognosis

Osteosarcoma prognosis depends on several factors, with overall survival rates generally improving with advancements in treatment. For localized osteosarcoma (no spread beyond the bone), the five-year survival rate is around 76%, while for tumors that have spread to nearby tissues or lymph nodes, it’s 64%. If the cancer has spread to distant parts of the body, the survival rate drops to 24%. A key factor influencing prognosis is the response to chemotherapy, with a good response (indicated by significant tumor cell death) leading to better survival rates.

Treatment

Osteosarcoma treatment typically involves a combination of chemotherapy and surgery, with radiation therapy sometimes used as well. The specific approach depends on the stage and location of the tumor, as well as the patient’s overall health. 

Treatment Options
  • Surgery:
    The primary goal is to remove the tumor. This may involve:

  • Amputation: Removing the entire limb, sometimes necessary for tumors in certain locations or when limb-sparing surgery is not feasible. 
  • Surgery for lung metastases: If the cancer has spread to the lungs, surgery may be an option to remove those tumors. 
  • Chemotherapy:
    Chemotherapy drugs are used to kill cancer cells throughout the body and are typically given before and after surgery. 

  • Commonly used drugs include methotrexate, doxorubicin, and cisplatin. 
  • Combinations like the MAP regimen (methotrexate, doxorubicin, and cisplatin) are often used, especially in children and young adults. 
  • Radiation Therapy:
    High-energy rays are used to kill cancer cells and can be used:
  • Before surgery to shrink the tumor. 

  • After surgery to kill any remaining cancer cells. 
  • When surgery is not an option. 
  • Other Treatments:

    Mifamurtide  (Mepact): A targeted therapy drug used in conjunction with chemotherapy after surgery for high-grade osteosarcoma in children, teens, and young adults. 

  • Targeted therapy: Drugs that target specific molecules involved in cancer cell growth. 
  • Bone-seeking radioactive drugs: Sometimes used to slow tumor growth and relieve pain in advanced cases. 
Important Considerations
  • Limb salvage vs. Amputation:
    While limb salvage is often possible, amputation may be necessary in some cases. 

  • Chemotherapy Timing:
    Chemotherapy is usually given before and after surgery to maximize its effectiveness. 

  • Clinical Trials:
    Clinical trials offer access to new and experimental treatments and may be an option for some patients. 

  • Supportive Care:
    Supportive care, including physical therapy, occupational therapy, and psychosocial support, is crucial for managing the side effects of treatment and improving quality of life.