Abstract
Purpose: To identify the risk of metastases at the time of diagnosis in patients with soft tissue sarcomas and to estimate the cost effectiveness of identifying these.
Methods: A retrospective database review was used to identify all new soft tissue sarcoma patients referred to our unit and to find those identified to have metastases at diagnosis. Data of tumour size, depth, grade, age, type of tumours, Chest x-ray (CXR)/CT chest results were available in all patients. We estimated the efficacy of CXR in identifying metastases and the costs of various staging strategies.
Patients: 1170 with newly diagnosed STS in 7.5 years (1996–2004) were included.
Results: The incidence of metastases at diagnosis was 10% (116 patients), 8.25% (96 patients) had lung metastases and 20 had metastases elsewhere. The risk of having lung metastases at diagnosis was 11.8% in high grade tumours, 6.95% in intermediate grade and 1.2% in low grade tumours. The risk increased almost linearly with size at presentation and was higher in deep tumours and older patients. CXR alone detected 2/3 of all lung metastases. The positive predictive value of the CXR was 93.7%, the negative predictive value was 96.7%, the sensitivity 62.5% and the specificity 99.6%.
The accuracy was 96.9%. CT overestimated metastases in 4%.
Discussion: We recommend that all patients with a newly diagnosed STS should have a CXR and only those with an abnormality or who have large, deep high grade tumours should have a CT chest. This strategy will save £7500 per 100 new patients with STS and will detect 93% of all chest metastases, missing 1 patient with metastases per 166 patients.
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