Prognostic Value of 18F-FDG PET/CT—Metabolic Parameters at Baseline and Interim Assessment in Pediatric Anaplastic Large Cell Lymphoma

Abstract

Introduction The event-free survival in pediatric anaplastic large cell lymphoma (ALCL) remains at 70% irrespective of the diverse chemotherapy regimens used. There is lack of valid prognostic factors identifying high-risk patients. We investigated the prognostic value of baseline metabolic parameters and interim response on 18F-FDG PET/CT in pediatric ALCL patients. Methods We retrospectively reviewed 40 pediatric ALCL patients with paired 18F-FDG PET/CT and treated uniformly on vinblastine-based institution protocol. The SUVmax, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis of the lymphomatous lesion were measured. Continuous PET parameters were stratified by their median values. Deauville scoring system was used to assess response to chemotherapy in the interim scan. Prognostic factors for overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method, log-rank test, and Cox proportional hazards model. Results At median follow-up of 52 months, 13 patients died and 13 had recurrence. On univariate analysis, higher whole-body MTV (WBMTV) and partial response on interim scan were statistically associated with OS. High-risk features, WBMTV, and partial response were statistically associated with DFS. On multivariate analysis combining baseline characteristics and interim response, interim response (hazard ratio, 3.56; P = 0.034) was statistically significant for OS. Multivariate analysis for DFS using only baseline characteristics revealed WBMTV as statistically significant (hazard ratio, 4.08; P = 0.035), but none of the parameters was statistically significant when baseline characteristics and interim response were evaluated together. Conclusions Whole-body tumor burden assessment with MTV and interim response may help to identify high-risk patients who might get benefitted from intensive therapy.

The Utility of Metabolic Parameters on Baseline F-18 FDG PET/CT in Predicting Treatment Response and Survival in Paediatric and Adolescent Hodgkin Lymphoma

“…However, tMTV was not found to be an independent prognostic factor for PFS [2]. This contrasts with the findings of Yang et al and Mathew et al, who recently demonstrated the utility of baseline tMTV as a prognostic marker in paediatric lymphoblastic lymphoma and paediatric anaplastic large cell lymphoma, respectively [6,8]. On the other hand, Chen et al found that baseline tMTV as well as TLG are both strong independent prognostic factors for paediatric NHL, outperforming other clinical-pathological risk factors (including serum LDH and bone marrow involvement on biopsy) in predicting survival [10].…”

“…In contrast, none of the metabolic parameters in question (SUV max , MTV, and TLG) featured as predictors for either PFS or OS, and only MTV was predictive of treatment response. Although the prognostic value of SUV max has been demonstrated in multiple studies, its reliability may be compromised by a host of factors, including but not limited to blood glucose levels, body weight, administered FDG dose (including the effects of extravasation), residual activity left in the syringe, decay of injected dose, uptake time, the presence of partial volume effects, and reconstruction parameters [2,[6][7][8][9]. In addition, SUV max is only measured by the highest image pixel in the tumor region and therefore does not show the metabolic activity of the entire tumor [17].…”

“…On the other hand, failure to demonstrate the prognostic value of MTV and TLG was somewhat unexpected, given that these metabolic parameters allow for measurement of the whole-body tumor burden [10][11][12]. MTV is the sum of voxels with an increased SUV inside the tumor lesion and represents the volume of viable tumor cells (the tumor volume with increased metabolism) [6,17]. TLG is the product of the MTV and SUV mean of the lesion and therefore reflects tumor metabolic activity and volume [8].…”

“…However, there is a paucity of data regarding the value of various metabolic parameters (namely whole-body metabolic tumor volume, [WB-MTV or tMTV] and total lesion glycolysis [TLG]) on baseline F-18 FDG PET/CT for riskstratification and prediction of OS and PFS. The most well-studied metabolic parameter, the maximum standard uptake value (SUV max ), is not always reproducible as its measurement is influenced by a number of different factors, and it is therefore not always reliable for prognostication [2,[6][7][8][9]. Metabolic volumetric parameters, on the other hand, give an indication of the whole-body tumor burden, and have recently been proposed as a valuable tool for prognostication.…”

Evolution of 18F-FDG Uptake as a Pitfall of Image Diagnosis for Systemic Anaplastic Large Cell Lymphoma

“…In particular, the PET scan is useful in identifying additional sites of disease in peripheral T cell lymphomas, including sALCL [5]. In addition, interim and post-treatment PET scans are useful in predicting treatment outcome [6].…”