To evaluate prognostic significance of metabolic-derived tumour volume at staging 18-flurodeoxyglucose PET-CT scan and to compare it with standardized uptake value-based response evaluation on interim 18-flurodeoxyglucose PET-CT scan in patients of non-Hodgkin's lymphoma (diffuse large B-cell lymphoma).

INTRODUCTION

To evaluate whether metabolic tumour volume (MTV) can be used as a prognostic indicator in patients with diffuse large B-cell lymphoma (DLBCL).

MATERIALS AND METHODS

Eighty-nine patients with DLBCL who underwent staging fluorodeoxyglucose PET-computed tomography (FDG PET-CT) scan were included in this study and followed up, up to a period of 5 years. Whole-body PET-CT was performed at staging and the total MTV of all FDG avid lesions was calculated for each patient at a threshold of 42% of SUVmax. Out of 89 patients studied, six patients had persistent disease after chemotherapy, 24 had recurrence during follow-up and 59 patients remained disease free. In this study, prognostic significance of the interim PET-CT scan was also analysed. Out of 89 patients, 81 underwent interim PET-CT scan. Receiver operator curve (ROC) analysis was done to determine MTV baseline cutoff along with sensitivity and specificity. For interim PET-CT scan prognostic evaluation, sensitivity and negative predictive value were calculated.

RESULTS

Among all 89 patients, the estimated area under the ROC curve was 0.851 and the MTV cutoff was 185.63 cm with sensitivity and specificity of 86.67% and 84.75%, respectively. In subset analysis of MTV cutoff, sensitivity and specificity were calculated for both the groups. For prognostic significance of the interim PET-CT scan, sensitivity and negative predictive value of staging MTV were much more than that of the interim PET-CT.

CONCLUSION

Baseline MTV can be used as a prognostic marker in DLBCL patients. Chemosensitive interim PET-CT scan is not a good prognostic marker compared with MTV.