207 Poster Session 2 - Connective Tissue Oncology Society

Scientific Posters – Poster Session 2Conclusion: This study demonstrated that the prognosisof chondrosarcoma of extremities and axial bones is relatedwith anatomical location, size of the tumor, pathologicgrade and surgical resection margin.Poster #136AVOIDING BIOPSY IN CHONDROID TUMORS:PROSPECTIVE PET-CT GRADING WITH EXCISIONSPECIMEN HISTOLOGICAL CORRELATIONPrakash R. Nayak, MD; Manish G. AgarwalOrthopedic Oncology, P.D. Hinduja Hospital, Mumbai, IndiaObjective: To prospectively evaluate role of PET CTgrading and staging of solitary chondroid tumors andHereditary Multiple Exostoses with the aim of avoidinga biopsy.Methods: Retrospective analysis of 45 chondroid lesions,4 patients with hereditary multiple exostoses(39 lesions)and 6 patients with unequivocal clinical and radiologicaldiagnosis of a solitary chondroid neoplasm from 2010 to2012 who underwent PET CT scan as a prospective stagingand grading modality was performed.A standardprotocol 10mCi dosage of FDG 18,followed 30 mins laterwith oral contrast agent trazogastro 10ml/500ml waterwas administered.An hour later PET CT images acquiredand reconstructed to obtain fused,trans-axial,coronal andsagital views of 3.7 mm thickness.SUV max based on ROI,after attentuation correction based on CT images were calculatedfor each lesion.Focal areas of asymmetric uptakewere noted.SUV max was correlated with final histologicalgrade on excision specimen and asymmetric ares werenoted for areas of de-differentiation.Results: All lesions grade 2 and 3 had an SUV averageof 7.5(3.4 to 11,n=4). De differentiated variant had anSUV of 38.4,with a sacral metastatic lesion having SUV10.1.Amongst 39 lesions in the Hereditary Multiple Exostosisgroup, only 3 grade 1 malignancies averaged SUV2.5.None of the lesions clinically silent had an SUVmax of>1.9(n=36).The lesions suspicious for chondrosarcomatouschange in the HME group averaged SUV 2.8(2.3 to 2.9,n=4).A cut off level 3 identified all 11 lesions with chondrosarcomatouschange grade 2 and above.Conclusion: PET CT is an important adjunct to conventionalimaging to stage and grade chondrosarcomas accurately.Thecurrent series although low in numbers tohave statistical significance has been 100 % accurate withan SUV cutoff of 3 for grade 2 and above chondrosarcoma.It has also been able to screen and have specificity in identifyingand grading chondrosarcomatous change in over39 lesions in 4 patients of HME,Although they behavedifferently than long and flat bone chondrosarcomas, theyhave been comparable with SUV pick up rates.They havecorrelated a 100 % with final post excision histology andhelped avoid a pre operative biopsy in all of the abovepatients.This in our knowledge is the first report with nopre surgical biopsy on chondroid lesions with success inthe entire cohort.casenumberagesexfinal histologicalgraderange ofSUVtotal number oflesionsSUV of excisedlesion(target lesion)1 61 male 0 1.3-1.5 13 1.52 30 male 1 2.7-3.4 9 3.43 6 male 0 0.9 to 1.8 8 1.94 16 male 1 1.3-2.8 9 2.85 44 female 2 11.1 1 11.16 52 male 4 10.1,38.4 2 38.47 38 male 2 4.01 1 4.018 34 female 1 7.3 1 7.39 56 male 2 4.4-5.1 2 5.110 38 female 1 2.7 1 2.7234