Investigations
1st investigations to order
CT scan of primary tumour
MRI of primary tumour
Test
MRI, with and without intravenous contrast, is the preferred imaging modality for the evaluation of primary soft-tissue tumours of the extremities, pelvis, and trunk.[11][38][39] Contrast improves differentiation of benign from malignant soft-tissue masses. If available, diffusion-weighted MR imaging, dynamic contrast-enhanced perfusion imaging, and MR spectroscopy may also aid differentiation of benign from malignant masses.[38]
Result
heterogeneous mass, with central necrosis; patchy contrast enhancement; usually dark on T1, bright on T2
CT scan chest
Test
Given the risk of haematogenous spread from high-grade sarcoma to the lungs, chest CT without contrast is essential for accurate staging.[11]
If any primary lesion appears to be malignant according to imaging criteria, a chest CT scan should be mandatory for all patients.[41][42][43]
Result
pulmonary metastases
biopsy for histology
Test
In order to establish the histological subtype and grade of a sarcoma, a core needle biopsy, fine needle biopsy, or fine needle aspiration should be done in all patients after diagnostic imaging.[11][39][44]
Pathology should be reviewed by an expert pathologist who has experience in reviewing sarcoma pathology. Pathologist might rely on immunohistochemistry, cytogenetics, and molecular genetic testing.[51]
Result
histological grade and type of sarcoma
Investigations to consider
abdominal/pelvic computed tomography
Test
Should be considered for patients with angiosarcoma, leiomyosarcoma, myxoid liposarcoma or epithelioid sarcoma, as well as soft-tissue sarcoma without definitive pathology.[11]
Result
metastases
magnetic Resonance Imaging (MRI) of total spine
Test
Should be considered for patients with myxoid cell liposarcoma due to a higher risk of metastasis to the spine compared with other soft-tissue sarcomas.[11]
Result
metastases
fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT)
endoscopy
Test
Those presenting with gastrointestinal bleeding should be referred for endoscopy as part of the work-up.
Result
tumour
full blood count (FBC)
Test
An FBC should be performed for all patients prior to chemotherapy.
Patients presenting with gastrointestinal bleeding should have an FBC and coagulation profile performed to determine if there is any anaemia or clotting abnormality requiring correction.
Result
normal; may show anaemia in gastrointestinal bleeding associated with gastrointestinal stromal tumours
coagulation studies
Test
Patients presenting with gastrointestinal bleeding should have a full blood count and coagulation profile performed to determine if there is any anaemia or clotting abnormality requiring correction.
Result
normal; may show abnormality in patients with gastrointestinal bleeding
urea
Test
Renal function should be tested in all patients prior to chemotherapy.
Result
normal
creatinine
Test
Renal function should be tested in all patients prior to chemotherapy.
Result
normal
liver function tests (LFTs)
Test
Liver function should be tested in all patients prior to chemotherapy.
Result
normal prior to chemotherapy; may be elevated if hepatic involvement or spread
echocardiogram or multi-gated acquisition (MUGA) scan
Test
In some cases, where treatment may involve cumulative doses of doxorubicin, formal evaluation of cardiac function (e.g., by gated blood pool scan or echocardiogram) may be indicated.[46][47][48]
This may particularly apply to patients receiving curative treatments for the paediatric sarcomas (rhabdomyosarcoma and Ewing's sarcoma).[49][50]
Result
uneven distribution of technetium in the heart and/or decreased ejection fraction during a MUGA scan is indicative of heart disease; an echocardiogram can evaluate multiple cardiac parameters, including ejection fraction, which may be diminished in patients with heart disease
ancillary techniques
Test
Diagnosis of soft-tissue sarcoma with microscopic examination of histology sections is the gold standard, however several ancillary techniques may be useful in supporting the diagnosis including immunohistochemistry, classical cytogenetics, electron microscopy and molecular genetics:[11]
Molecular testing uses multiple techniques, including next-generation sequencing (NGS) - based methods (including DNA and RNA sequencing) which can determine patient eligibility for clinical trials, identify actionable mutations that may not have been targeted previously, and select patients who may benefit from immunotherapy.[11]
If the physician or pathologist is suspicious of a translocation-associated sarcoma, then appropriate gene rearrangement testing should be carried out to accurately diagnose the sarcoma subtype.[45]
Result
specific genetic syndromes
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