The aim of this study was to explore the positive predictive value and negative predictive value of FDG PET/CT. The prognostic impact of tumor burden of bone marrow infiltrates was diagnosed by FDG PET/CT at initial presentation.
This retrospective study enrolled 140 pediatric patients with pathologically proven lymphoma (113 Hodgkin disease and 27 Non-Hodgkin lymphoma). All patients had pretherapy FDG PET/CT. Bone marrow biopsy (BMB), clinical, radiological, and follow-up data were also collected. The skeleton was divided into 8 segments, and a 5-point scoring system was used for assessment of BM infiltration burden.
Among the 140 lymphoma patients, FDG PET/CT revealed positive BM involvement in 41 patients; 2 of them were false-positive with negative BMB and regional MRI results. Positive predictive value was 95.1% for PET/CT compared with 100% with BMB. All patients diagnosed with positive BMI by BMB were detected by FDG PET/CT. On the contrary, BMB missed 25 patients (17.9%) with statistically significant difference. Negative predictive value was 100% for PET/CT compared with 80.2% for BMB (P < 0.05). FDG PET/CT upstaged 17.9% of the enrolled patients. Bone marrow involvement based on the 5-point scoring system was assessed. No significant difference was demonstrated in therapy outcome between patient with focal BMI (score 2) and extensive BMI (score 5; P = 0.06).
FDG PET/CT has optimum negative predictive value compared with BMB in detection of bone marrow infiltrations in pediatric lymphoma with upstaging cases missed with BMB. Prognostic impact of BMI based on the 5-point scoring system reveals that the main influence is presence or absence of BMI rather than its tumor burden.
From the *Nuclear Medicine Unit, National Cancer Institute, Cairo University;
†Children's Cancer Hospital; and
‡Nuclear Medicine Unit, Kasr Al-Ainy (NEMROCK Center), Cairo University, Cairo, Egypt.
Received for publication June 22, 2018; revision accepted September 5, 2018.
Conflicts of interest and sources of funding: none declared.
Authors' contributions: S.B. and M.A.E. conceived of the presented idea and wrote the manuscript with support from M.K.; M.K. helped in data interpretation and manuscript evaluation; H.M. participated in analysis and interpretation of data and supervised the findings of this work. All authors revised and gave final approval of the version to be submitted.
Availability of data and materials: Further data are available upon request. Please contact the corresponding author.
Correspondence to: Mai Amr Elahmadawy, MD, PhD, Nuclear Medicine Unit, National Cancer Institute, Cairo University, 1, Foam El-Khalig, El-Kasr Elaini St, Cairo 11796, Egypt. E-mail: Mai_4a@yahoo.com.