The importance of PET/CT in the evaluation of patients with Ewing tumors

Abstract

The effective evaluation for the treatment of patients with Ewing tumors depends on the accuracy in the determination of the primary tumor extent and the presence of metastatic disease. Currently, no universally accepted staging system is available to assess Ewing tumors. The present study aimed at discussing the use of PET/CT as a tool for staging, restaging and assessment of therapeutic response in patients with Ewing tumors. In spite of some limitations of PET/CT as compared with anatomical imaging methods, its relevance in the assessment of these patients is related to the capacity of the method to provide further physiological information, which often generates important clinical implications. Currently, the assessment of patients with Ewing tumor should comprise a study with PET/CT combined with other anatomical imaging modalities, such as radiography, computed tomography and magnetic resonance imaging.

Ewing’s Sarcoma: imaging findings of a patient with primary tumor in the femur and mandibular metastasis

“…Therefore, an accurate assessment of patients with ES must be made to detect the extent of the primary tumor and a possible metastasis, to ensure an effective treatment. The association of the conventional imaging methods such as radiography, CT, MRI, combined with scintigraphy or Positron Emission Tomography/ Computed tomography PET /CT) that assess the metabolic activity of cancer cells, is essential for correct diagnosis of ES [24]. In the present case, MRI demonstrated the extension of the primary lesion and its relationship with the other anatomic structures such as the muscles.…”

“…However, these methods only are limited for this evaluation. In this case, the association of other imaging methods such as scintigraphy or PET/CT should have been performed initially to detect metastasis and to evaluate the therapeutic response [24]. Scintigraphy detects metastasis indirectly by bone remodeling and PET/CT identifies lesions based on metabolic activity.…”

Prognostic value of FDG-PET indices for the assessment of histological response to neoadjuvant chemotherapy and outcome in pediatric patients with Ewing sarcoma and osteosarcoma

“…A number of clinical and pathologic features with prognostic significance have been reported including age, gender, tumor site, size, stage, histologic subtype and histologic response to pre-operative CHT[ 6 , 7 ]but often with contradictory results due to the lack of uniformity in patient analyses and methods. In particular, despite a potential impact of age on the prognosis of bone sarcoma patients, some of these studies mixed adult and pediatric populations[ 10 , 16 , 24 ]. In this context, the purpose of this retrospective work was thus to evaluate the prognostic value of FDG-PET in a pediatric bone sarcoma population including homogeneous subgroups of EWS and OST both for staging and response assessment.…”

Current update on the diagnosis and management of head and neck hard tissue sarcomas

“…One study identified that it is useful in stratifying patients with high‐grade EWS who would benefit from risk‐adapted induction chemotherapy . However, it has been advised that it should be used in combination with other imaging modalities …”