Utility of whole-body (head-to-toe) PET/CT in the evaluation of melanoma and sarcoma patients.

Abstract

The aim of this study was to assess the added benefit of whole-body (head-to-toes) PET/CT versus routine 'eyes-to-thighs' PET/CT of melanoma and sarcoma patients. We performed a retrospective review of consecutive whole-body PET/CT scans from January 2006 through December 2010 in patients with melanoma or sarcoma. PET abnormalities in the brain, distal thighs, and legs were recorded and clinical significance was assessed on the basis of pathology, imaging studies, and clinical follow-up. Patients with known primary lesions distal to the proximal femora were excluded as these patients would routinely undergo 'head-to-toe' PET/CT. We reviewed reports from 352 PET/CT examinations in 194 patients with melanoma and 75 PET/CT examinations in 44 patients with sarcoma. Melanoma: 13 patients had brain metastases on PET. In five of these patients, lesions were unknown, but all were in the setting of other metastatic disease. Twenty-seven patients had lower extremity metastases, all in the setting of other metastatic disease. No lower extremity metastases were found in the remaining 167 patients. Sarcoma: one patient had an isolated, unexpected brain metastasis. Six patients had leg metastases, but none were isolated. No lower extremity metastases were found in the remaining 38 patients. In patients with melanoma and sarcoma, inclusion of entire lower extremities adds little additional clinical value as detection of isolated, unexpected metastasis is rare. Brain imaging may add value as the presence of brain metastases alters clinical management. Overall, in patients with melanoma or sarcoma, whole-brain PET/CT imaging may be of value, but routine inclusion of the entire lower extremities adds little additional value.