The Role of FDG- PET/CT in Detecting Bone Marrow Involvement in Childhood Solid Tumors.

Purpose: To compare the results of 18F-Fluorodeoxy positron emission tomography/computed tomography (18 F-FDG-PET/CT) and bone marrow biopsy (BMB) procedures in the initial evaluation of bone marrow involvement (BMI) in pediatric solid tumors.

Methods: We conducted a retrospective analysis of newly diagnosed pediatric cases with lymphoma, neuroblastoma, Ewing sarcoma, rhabdomyosarcoma. Each case underwent both PET-CT imaging and BMB. Presence of tumor infiltration in BMB specimens and/or positive FDG-PET/CT findings indicate as BMI were regarded as true positive results.

Results: Sixty-four patients were included in the study. BMI was detected in 23/64 (36%) patients, FDG-PET/CT imaging and BMB results were concordant in 54/64 patients. In 9/64 patients the finding was FDG-PET/CT (+), BMB (-) indicating a false negative BMB result. In only 1/64 patients FDG- PET/CT (-), BMB (+), indicating a false negative FDG-PET/CT result. In the whole patient group, the sensitivity, specificity, positive predictive value and negative predictive value of PET/CT and BMB in detecting bone marrow involvement were 95.6%, 100%, 100% and 97.6% and 60.8 %, 100%, 100% and 82%, respectively.

Conclusion: PET/CT has a high sensitivity and specificity for the assessing marrow involvement in pediatric solid tumors. We believe that PET/CT imaging should be performed as the first step in diagnostic staging, and BMB may not be necessary in every patient, only in patients with suspicious PET/CT results for bone marrow involvement. Additionally, for a more precise determination of bone marrow involvement, it is reasonable to perform BMB from FDG-retaining areas, using PET/CT as a guide tool.