Correlation of ¹⁸F FDG PET SUVmax with the cell of origin classification of diffuse large B-cell lymphoma

Depending on the cell of origin DLBCL can be broadly classified into two groups, Germinal center B –Cell like subtype (GCB) and non GCB group or Activated B-cell (ABC) subtype. Non-GCB DLBCL is known to be associated with unfavorable prognosis. However, correlation between the COO classification and SUV parameters have rarely been investigated and the literature regarding it is pretty scarce. In this study, we aim to see if there is any correlation between SUVmax and COO subtypes of DLBCL as predicted by the Hans algorithm. Mann-Whitney U Test was used to assess the mean SUVmax between GCB and non GCB DLBCL. ROC analysis and Youden Index was used to find a SUVmax cut off. Chi square test was used to further validate the cut off. Using ROC analysis a SUVmax cutoff of 20 was found (sensitivity = 83%, specificity 43%, AUC = 0.670, p value = 0.014). Using this cut off 73% of the cases with SUVmax <20 were correctly identified as GCB subtype and 60% of the cases with SUVmax > 20 were correctly identified as non GCB subtype (p value 0.019). SUVmax in GCB subtype of DLBCL was found to be significantly higher than that of non GCB type DLBCL, however the effect size was moderate. Correlation of various IHC markers with other metabolic and PET radiomic parameters may provide more robust data