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Abstract: 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) is a valuable prognostic tool in modern lymphoma care. In this study, we explored the use of quantitative FDG-PET parameters in predicting the histology of suspected relapsed or refractory (R/R) lymphoma. We retrospectively analyzed 290 FDG-PET scans performed for suspected R/R lymphoma. FDG-PET parameters measured were maximum and mean standardized uptake value (SUVMax and SUVMean), total metabolic tumor volume, and total lesion glycolysis (TLG). Receiver operating characteristic curve analysis was used to obtain the optimal thresholds that best discriminate (1) benign vs R/R lymphoma, (2) indolent vs aggressive non-Hodgkin lymphoma (NHL), and (3) aggressive transformation of indolent NHL. We found that although all 4 FDG-PET parameters discriminated R/R lymphoma from benign histology, TLG was the best performing parameter (optimal cut-off ≥245, sensitivity 63%, specificity 86%, positive predictive value [PPV] 97%, negative predictive value [NPV] 30%, area under the curve [AUC] 0.798, and P < .001). SUVMax discriminated aggressive from indolent NHL with modest accuracy (optimal threshold ≥15, sensitivity 46%, specificity 79%, PPV 82%, NPV 38%, AUC 0.638, and P < .001). In patients with a prior diagnosis of indolent NHL, SUVMax was a modest predictor of transformation (optimal cut-off ≥12, sensitivity 71%, specificity 61%, PPV 50%, NPV 78%, AUC 0.676, and P .006). Additionally, SUVMax ≥25 and an increase in SUVMax (ΔSUVMax) from baseline ≥150% were highly specific (96% and 94%, respectively). These FDG-PET thresholds can aid in identification of suspected R/R lymphoma cases with higher likelihood of R/R disease and aggressive transformation of indolent NHL, guiding the necessity and urgency of biopsy., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Interim FDG‐PET (iPET) in diffuse large B‐cell lymphoma (DLBCL) is increasingly practised and used in clinical trials to adapt further therapy. However, the optimum timing and methodology of iPET remains controversial. We retrospectively analysed the iPET results and outcomes of 200 DLBCL patients where FDG‐PET was routinely performed at baseline, after 2 cycles (iPET2) and at completion of chemoimmunotherapy. iPET was also performed after 4 cycles (iPET4) where at iPET2, Deauville score (DS) was ≥4. Scans were assessed by blinded expert lymphoma PET physicians for DS, maximum standard uptake value (SUVmax), total metabolic tumour volume (TMTV) and total lesion glycolysis (TLG). Treatment failure was defined as death, progression or refractory disease. 95.5% of patients received R‐CHOP. No baseline PET parameter was predicted for EFS or OS independent of the NCCN‐IPI. The multivariable analysis at iPET2 showed DS5 (19.5% of cases) predicted treatment failure (HR 6.29, 95% CI 3.01‐13.17, P <.001), but DS4 was equivalent to DS1‐3. At iPET4, ΔSUVmax < 66% predicted treatment failure (HR 5.49, 95% CI 3.03‐9.99, P <.001). By multivariable analysis of all time points, high NCCN‐IPI and DS5 at iPET2 were negative predictors of survival. These findings were independent of novel prognostic markers. [ABSTRACT FROM AUTHOR]

Summary: Elderly patients may be heterogeneous in their abilities to tolerate immunochemotherapy‐associated toxicities. We describe the morbidity of rituximab‐chemotherapy combinations among 205 newly‐diagnosed diffuse large B‐cell lymphoma (DLBCL) patients aged ≥60 years from 3 tertiary hospitals between 2009 and 2016, and explore the utility of retrospectively‐assigned baseline Comprehensive Geriatric Assessment (CGA) in predicting these toxicities. Seventy‐three percent (146/201) experienced grade ≥3 toxicities, 81% (163/201) needed admission, 52% (107/205) had ≥2 unplanned admissions, 82/201 (41%) required dose reductions (DR) subsequent to Cycle 1, 39/166 (23%) had chemotherapy delays and 26/198 (13%) ceased therapy early. CGA was associated with pre‐emptive baseline DR and perhaps because of this, did not predict grade ≥3 toxicities, ≥2 unplanned admissions or subsequent DR. Three‐year overall survival (OS) of CGA‐fit, CGA‐unfit and CGA‐frail patients was 82%, 60% and 53%, respectively. Three‐year progression‐free survival (PFS) of CGA‐fit, CGA‐unfit and CGA‐frail patients was 66%, 58% and 46%, respectively. OS of CGA‐fit patients was not statistically different from CGA‐unfit patients, but was superior to CGA‐frail patients (hazard ratio 2·892, 95% confidence interval 1·275–6·559, P = 0·011). PFS differences were not statistically significant. Baseline DR and early therapy cessation were associated with inferior OS and PFS independent of CGA. Prospective studies are needed to confirm if CGA‐adapted treatment strategies minimize morbidity and improves survival. [ABSTRACT FROM AUTHOR]