Over the past few years, many papers have been published by groups investigating the utility of 18F-fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) for screening and therapy response assessment in various lymphoma subtypes. Several of these studies have reported the value of total metabolic tumor volume (TMTV) as a negative or positive prognostic indicator, based on a TMTV above or below a predetermined threshold at baseline, or as an indicator of response according to a change in TMTV over a course of treatment. Different approaches have been investigated for segmenting lesions for volume measurement, including the setting of image thresholds at fixed percentages of lesion maximum standard uptake values (SUVmax), e.g. the 41% of SUVmax suggested by the European Association of Nuclear Medicine (EANM); absolute SUV, e.g. SUV≥2.5; or a multiple of a reference value such as 2.5 times the Liver SUVmean. Although more than one group have concluded that the selection
of the most sensitive baseline TMTV cutoff for the purpose of prognostic determination appears to be disease specific, there is consensus that most, if not all, of the approaches to threshold setting have similar prognostic or response results when the selected method is applied consistently. In addition, at least one group of researchers have reported that FDG-PET-based TMTV evaluations are superior to approaches such as measurements of anatomical size or bulk or qualitative PET assessments such as
numerical scoring systems in terms of predicting outcomes or demonstrating response to treatment.
FDG-PET-based TMTV measurement brings useful, independent and correlative information to the clinical drug evaluation process. Bioclinica can customize the segmentation threshold settings to meet any special requirements based on disease type or sponsor request or can provide measurements based on multiple approaches to segmentation for sponsor downstream evaluation if desired. Additional data, such as Total Lesion Glycolysis (TLG) based on the TMTV(s) can also be provided for prognostic/response evaluation and can be included in the data provided to the sponsor for a comprehensive demonstration of drug efficacy.
1. Cottereau A.-S., Hapdey S., Chartier L., Modzelewski R., Casasnovas O., Itti E., Tilly H., Vera P., Meignan M., Becker S. Baseline Total Metabolic Tumor Volume Measured with Fixed or Different Adaptive Thresholding Methods Equally Predicts Outcome in Peripheral T Cell Lymphoma. J. Nucl. Med. 2016;58:276–281
2. A. S. Cottereau, S. Becker, F. Broussais et al., “Prognostic value of baseline total metabolic tumor volume (TMTV0) measured on FDG-PET/CT in patients with peripheral T-cell lymphoma (PTCL),” Annals of Oncology, vol. 27, no. 4, pp. 719–724, 2016
3. Burggraaff CN, Rahman F, Kaßner I, Pieplenbosch S, Barrington SF, Jauw YWS, et al. Optimizing workflows for fast and reliable metabolic tumor volume measurements in diffuse large B cell lymphoma. Mol Imaging Biol. 2020;22:1102–10