Osteosarcoma – An Evaluation of Current Diagnosis, Treatment and Chemotherapy
Table 1: Surgical Staging of Bone Sarcomas Enneking Staging System
Stage IA IB
IIA IIB III
IVA IVB IVB
Grade Low Low High High Any - - -
Site
Intracompartmental Extracompartmental Intracompartmental Extracompartmental Any - - -
Sources: Enneking et al., Clin Orthop Relat Res, 1980:106–20. 11
Metastasis No No No No
Regional or distant - - -
Size and Site Lymph Node ≤8 cm >8 cm ≤8 cm >8 cm Skip Any Any Any
No No No No No No
Yes Any
American Joint Committee on Cancer Staging System Metastasis No No No No No
Lung Any
Other
Grade Low Low High High Any Any Any Any
and Li-Fraumeni syndrome – suggests that gene mutations may play a role in its pathogenesis.3,6,19,20
Characteristics
Despite success with a combination of surgery and chemotherapy, local recurrence and metastases (usually at the lungs) develop in approximately 30–40% of all patients and appear to be the major cause of death.3,21,22
Bone metastases usually only become
Tumour nodules growing outside the reactive zone, but within the same bone or across the neighbouring joint, are termed ‘skip lesions’.23
established after pulmonary metastases have occurred. Following metasteses in the lungs, bone appears to be the second major site of metastases.17 uncommon.17
Diagnosis Symptoms and Signs Pain and swelling are the major symptoms of osteosarcoma.6 Pain
usually arises after exercise or a trauma and progresses over time. Swelling appears later, with a hard painful mass in the affected region. Osteosarcoma is also rarely associated with anorexia, weight loss, fever and fatigue.3,24
Laboratories
Laboratory findings may show an increase in alkaline phosphatase activity and in 30% of cases an increase in lactic dehydrogenase level in the serum. Mild anaemia may also be present at diagnosis. Furthermore, the erythrocyte sedimentation rate is often high and increases with relapse.25
In the absence of metastases, abnormal
alkaline phosphatase values are correlated with tumour volume and prognosis.3,26–28
Imaging
Direct communication between the radiologist and orthopaedic surgeon would therefore be helpful in determining the diagnosis. Once osteosarcoma is suspected, the patient should undergo an advanced imaging procedure for confirmation. Advanced imaging is performed to more precisely define the extent of the primary tumour and assess its location relative to the adjacent bones, muscles, joints, blood vessels and nerves.29
Imaging techniques play an important role in osteosarcoma diagnosis and treatment.29
Visualisation of the tumour on plain X-rays can help in diagnosis. Typically, patients with extremity osteosarcoma have poorly defined lytic and sclerotic lesions involving the metaphyseal part of the bone. Cortical destruction with lifting of the periosteum – ‘Codman’s
EUROPEAN MUSCULOSKELETAL REVIEW Other metastatic sites at diagnosis are very
triangle’ – is often present. Some cases display the ‘sunburst’ pattern, with suggestion of bone spicule formation within the tumour.1 Computed tomography (CT) and magnetic resonance imaging (MRI) have been used to investigate the extension of tumours and the involvement of surrounding structures, such as vessels, nerves and soft tissues.3,30
CT of the lung is part of the basic staging of osteosarcoma. High-resolution CT scans and spiral technique can be performed with 5mm or less collimation and is preferably imaged during a single breath-hold.29,31
In children with osteosarcoma, it is recommended that single photon emission CT be performed in conjunction with planar whole-body scintigraphy to characterise uptake at the primary tumour site.32
It is also recommended in suspected lung metastases.29
MRI has the ability to predict tumour necrosis before surgical resection and remains an exciting prospect for osteosarcoma.32
The
MRI should include long-axis imaging with T1 and/or short tau inversion recovery (STIR) sequences performed through the entire bone involved to assess the extent of the tumour and the presence of ‘skip’ metastases. Axial imaging with fast-spin echo T2 weighted sequences with fat saturation or STIR sequences through the tumour are best to determine the relationship of the tumour to the adjacent soft tissues and vascular structures. Gradient echo sequences can be added to confirm flow within the blood vessels. Post-gadolinium T1 weighted fat-saturated sequences are helpful in determining areas of tumour necrosis. Relatively small field of view imaging in two planes is recommended to assess joint involvement.29,32,33
An isotope scan
with technetium or thallium can show the intense hotspot of the tumour and any skip or distant bone metastases.3,23,30
Positron
emission tomography (PET) scans are not routinely performed in osteosarcoma patients yet. Despite this, there are limited studies that show PET scans may be useful in predicting response to chemotherapy and in differentiating post-operative changes from recurrent tumour.1,34,35
Biopsy
Incorrectly performed biopsies are a cause of misdiagnosis, amputation and local tumour recurrence.3,23 negative effect on survival.3,23
Biopsy is a main diagnostic method for osteosarcoma. The biopsy should be carefully planned, with a multidisciplinary approach involving musculoskeletal radiologist, pathologist and orthopaedic or surgical oncologist. This will be essential to ensure the feasibility of the procedure, the adequacy of the specimen and above all to maintain the viability of definitive surgery with a possibility of limb salvage.36
They may also have a
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