Predictive value of F-FDG PET/CT in adults with T-cell lymphoblastic lymphoma: post hoc analysis of results from the GRAALL-LYSA LLO3 trial.

PURPOSE

We examined whether FDG PET can be used to predict outcome in patients with lymphoblastic lymphoma (LL).

METHODS

This was a retrospective post hoc analysis of data from the GRAAL-LYSA LL03 trial, in which the treatment of LL using an adapted paediatric-like acute lymphoblastic leukaemia protocol was evaluated. PET data acquired at baseline and after induction were analysed. Maximum standardized uptake values (SUV), total metabolic tumour volume and total lesion glycolysis were measured at baseline. The relative changes in SUV from baseline (ΔSUV) and the Deauville score were determined after induction.

RESULTS

The population analysed comprised 36 patients with T-type LL. SUV using a cut-off value of ≤8.76 vs. >8.76 was predictive of 3-year event-free survival (31.6% vs. 80.4%; p = 0.013) and overall survival (35.0% vs. 83.7%; p = 0.028). ΔSUV using a cut-off value of ≤80% vs. >80% tended also to be predictive of 3-year event-free survival (40.0% vs. 76.0%; p = 0.054) and overall survival (49.2% vs. 85.6%; p = 0.085). Total metabolic tumour volume, baseline total lesion glycolysis and response according to the Deauville score were not predictive of outcome.

CONCLUSIONS

A low initial SUV was predictive of worse outcomes in our series of patients with T-type LL. Although relatively few patients were included, the study also suggested that ΔSUV may be useful for predicting therapeutic efficacy.