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Limb-salvage surgery carries amputation risk
Published on: Tuesday, May 07, 2019

Family physician and orthopedists rarely see a malignant bone tumour (most bone tumours are benign). The route to osteosarcoma diagnosis usually begins with an X-ray (pic), continues with a combination of scans (CT scan, PET scan, bone scan, MRI) and ends with a surgical biopsy.

A characteristic often seen in an X-ray is Codman’s triangle, which is basically a subperiosteal lesion, formed when the periosteum is raised due to the tumour.

Films are suggested but bone biopsy is the only method to determine whether a tumour is malignant or benign. Most times, the early signs of osteosarcoma are caught on X-rays taken during routine dental check-up. Osteosarcoma frequently develops in the mandible (lower jaw); accordingly.

Dentists are trained to look for signs that may suggest osteosarcoma. Even though radiographer findings for cancer vary greatly, one usually sees a symmetrical widening of the periodontal ligament space.

If the dentist has reason to suspect osteosarcoma or another underlying disorder, he or she would refer the patient to an Oral & Maxillofacial surgeon for biopsy.

A biopsy of suspected osteosarcoma outside of the facial region should be performed by an orthopaedic oncologist.

The American Society states: “Probably in no other cancer is it as important to perform this procedure properly. An improperly performed biopsy may make it difficult to save the affected limb from amputation”.

It may also metastasize to lungs, mainly appearing on the chest X-ray as solid or multiple round nodules most common at lower regions.

The various kinds of osteosarcoma include

 
  • conventional osteoblastic, chondoblastic, fibroblastic
  • Telagiectatic
  • Small cell
  • Lower grade central
  • Periosteal
  • Paraosteal
  • Secondary
  • High grade surface
  • Extra-skeletal


 

Treatment

A complete radical, en bloc resection of the cancer, is the treatment of choice in osteosarcoma. Although 90 per cent of the patients are able to have limb-salvage surgery, complications, particularly infection, prosthetic loosening and non-union, or local tumour recurrence may cause the need for further surgery or amputation.

Mifmurtide is used after a patient has had surgery to remove tumour and together with chemotherapy to kill remaining cancer cells to reduce the risk of cancer recurrence. Also, option to have rotationplasty after the tumour is taken out exists. Patients with osteosarcoma are best managed by a medical oncologist and an orthopaedic oncologist experienced in managing sarcomas.

Current standard treatment is to use neoadjuvant chemotherapy (chemotherapy given before surgery) followed by surgical resection. The percentage of tumour cell necrosis (cell death) seen in the tumour after surgery given an idea of the prognosis and also lets oncologist know if the chemotherapy regimen should be altered after surgery. Standard therapy is a combination of limb-salvage orthopaedic surgery when possible (or amputation in some cases) and a combination of high dose methotrexeate with lenocovrin resue, intra-arterial cisplatin, adriamycinh, ifosafamide with mesna.

BCD (bleomycin, cyclophosphamide, dactinomycin), etoposide, andmuramyl tripeptide. Rotationplasty may be used. Ifosfamide can be used as an adjuvant treatment if the necrosis rate is low. Despite the success of chemotherapy for osteosarcoma, it has one of the lowest survival rates of pediatric cancer. The best reported 10-year survival rate is 92 per cent, the protocol used is an aggressive intra-arterial regimen that individualises therapy based on arteriography response. 

Three years event free survival ranges from 50 -75 per cent and five year survival ranges from 60-85 per cent in some studies. Overall, 65-70 per cent patients treated five years ago will be alive. These survival rates are overall averages and vary greatly depending on the individual necrosis rates. Filgratism or pegfilgrastin hel with white blood cell counts and neutrophil counts. Blood transfusion and epoetin alfa help with anemia. Computational analysis on a panel of osteosarcoma cell lines identified new shared and specific therapeutic targets (proteomic and genetic) in osteosarcoma, while phenotypes showed an increased role of tumour microenvironments.

 

Disease outcome

Prognosis of osteosarcoma is divided into three groups:

Stage One: Osteosarcoma is rare and includes parosteal osteosarcoma or low grade osteosarcoma. It has an excellent prognosis (>90 per cent) with wide section.

Stage Two: Stage two prognosis depends on the site of the tumour (proximal tibia, femur, pelvis, etc), size of tumour mass and the degree of necrosis from neoadjuvant chemotherapy. Other pathological factors such as the degree of p-glycoprotein, whether the tumour is cxcr4-positive or Her2-positive are also important, as these are associated with distant metastases to the lung. The prognosis for patients with metastatic osteosarcoma improves with longer times to metastases (more than 12 months to 4 months), a smaller number or metastases, and their resectability. It is better to have fewer metastases than longer time metastases. Those with a longer length of time (more than 24 months) and fewer nodules (two or fewer) have the best prognosis, with two year survival after metastases of 50 per cent, five year of 40 per cent and 10 year of 20 per cent. If metastases are both local and regional, the prognosis is worse.

Stage Three: At initial stage of stage three osteosarcoma with lung metastases depends on the resectability of the primary tumour and lung nodules, degree of necrosis of the primary tumour and, maybe, the number of metastases. Overall survival prognosis is about 30 per cent.

Deaths due to malignant neoplasms of the bones and joints accounts for an unknown number of childhood cancer deaths. Mortality rates due to osteosarcoma have been declining at about 1.3 per cent per year. 

Long term survival probabilities for osteosarcoma have improved dramatically during the late 20th century and approximated 68 per cent in 2009.

This series on osteosarcoma concludes next week, with a look at tumours and the ailment’s impact on domestic pets.

 





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