Osteosarcoma

Origin and causes

Osteosarcoma is the most common primary bone malignancy in children and adolescents. It occurs more frequently during the 2nd decade, but can also affect older patients (around 65 years) and may present secondarily to an underlying benign lesion (such as Paget's disease) or following prior radiation therapy. Some patients with genetic syndromes such as Li-Fraumeni syndrome may be at risk of developing osteosarcoma. However, the vast majority of osteosarcoma patients have no identifiable risk.

 

Symptoms and signs

Osteosarcoma commonly affects the metaphysis of long bones (i.e. femur), but can present in any bone in the body. Early symptoms are often of progressive pain followed by swelling of the area affected by the sarcoma. Some patients may present with pulmonary or bone metastases at the time of diagnosis.

 

Diagnosis

When a sarcoma is suspected, the initial evaluation includes either a CT scan or MRI. The diagnosis is made by a biopsy of the suspected area. The biopsy can be performed in the operating room or by the radiology team under local anesthesia. The pathology team will then confirm the diagnosis after analyzing the samples. The evaluation can be complemented with a thorax CT scan and a PET scan.

 

Treatment

When osteosarcoma is localized, the treatment of choice is surgery with the goal of removing it all. Given that osteosarcoma is an aggressive cancer that can cause metastases, pre-operative and post-operative chemotherapy may be necessary. The most commonly used chemotherapy protocols are MAP or Cisplatin-Doxorubicin.

 

In case metastases are found, chemotherapy is offered with the goal of controlling symptoms and disease progression. The agents of choice are: Cisplatin-Doxorubicin, Ifosfamide-etoposide, gemcitabine-docetaxel, cabozantinib or regorafenib. Clinical trials may also be explored.

 

Follow-up

After surgery, osteosarcoma patients will be closely monitored due to the risk of recurrence (when the cancer returns). The follow-up will be every 3 months for the first two years, then every 6 months up to 5 years. After that, visits will be spaced out to every year until 10 years.