The management of pulmonary nodules at diagnosis in patients with Ewing sarcoma (ES).

Abstract

9527 Background: Cure rates for metastatic ES are poor and justify the stratification of treatment protocols by the presence of metastases at diagnosis. Lung metastases (mets) are the most common form of disseminated disease. Our goal was to assess the diagnostic performance of CT imaging of nodules at diagnosis to discriminate benign from malignant lesions. Methods: We reviewed the CT scan of all patients (pts) treated at four French centres, prospectively enrolled on the EuroEwing 99 trial between January 1999 and December 2009. Results: 342 patients were identified, 141 of whom had lung nodules at diagnosis, 18 with extra-pulmonary mets. Among the 123 other pts, 54 were considered as having lung mets without needing a biopsy (bx), 32 non-metastatic without needing a bx and 37 with doubtful lung lesions had a bx as part of the disease staging process. Of those 37 pts, three had lesions identified on plain chest x-ray and 35 had nodules only detected by CT. 16 pts had unilateral nodule(s). Bx showed lung mets in 21 and benign lesions in 16. The median number of nodules detected for the bx positive group was 4 (range 1-22) and 2 for the bx negative group (range 1-12). The median size of the largest nodule was 6 mm (range 3-15) for the bx positive group and 3mm for the bx negative group (range 1.5-8). Both ROC curves showed the poor diagnostic performance of the number of nodules and the size of the largest considered separately and advocate for combining the 2 criteria. According to the practice guidelines of the protocol 47 pts had nodule characteristics that placed them in the “treat as lung metastases without bx.” Among those, 11 had a bx, of which 9 were positive. All 7 pts with more than 2 nodules and largest nodule greater than 6 mm were metastatic, but 2 of 4 patients with more than 2 nodules the largest being 6 mm were not metastatic. 20 of 42 pts classified as requiring a bx had a bx, 11 of which were positive. Of the 22 pts for whom “bx was to be discussed on a case by case basis” five had a bx, which were all negative. Conclusions: Combining nodule imaging characteristics is appropriate. All patients with at least one nodule measuring between 3 and 10mm should have a lung biopsy. Nodules greater than 10mm in diameter can be considered metastatic.