Bone marrow evaluation in initial staging of lymphoma: 18F-FDG PET/CT versus bone marrow biopsy

The evaluation of bone marrow infiltration (BMI) is of crucial importance in the staging of lymphoma. Although bone marrow biopsy (BMB) is the reference standard for the evaluation of BMI, it has limitations. PET/CT has become an excellent tool in staging of lymphoma, and bone marrow uptake is correlated with the involvement of lymphoma. The aim of this study was to assess the utility of PET/CT and its concordance with BMB in the detection of BMI in patients with diffuse large B-cell lymphoma (DLBCL) and Hodgkin lymphoma (HL).

One hundred forty-seven patients with DLBCL (84) and HL (63) were referred for a PET/CT and a BMB (unilateral) at the initial staging. The reference standard was BMB.

Bone marrow infiltration was detected by PET/CT in 39 (26%) and by BMB in 21 (14%) cases. There was concordance between PET/CT and BMB in 128 patients (87%) (74 DLBCL, 54 HL), 21 with positive PET/CT and BMB results and 107 with negative PET/CT and BMB results. Discordant results were observed in 19 patients (14%); 18 of them with positive PET/CT and negative standard BMB results (not performed in active sites). The sensitivity, specificity, accuracy, as well as positive and negative predictive values of FDG-PET/CT for the detection of BMI were 95%, 86%, 87%, 54%, and 99%, respectively.

PET/CT detects more bone marrow involvement in DLBCL and HL compared with BMB. Its good concordance with BMB makes it a complementary technique, as it helps select the biopsy site in cases with negative results.