Background The role of fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied. Objective This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma. Methods We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months. Results SUVmax <4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (P=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax <4.35, versus 58.4% for SUVmax ≥4.35 (P=.13). The overall survival of patients with a baseline DC score <3.0 was 100%, with a median overall survival of 106.67 months. Conclusions We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (<4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS.

Background: Indolent lymphomas (ind-LYM) are a subset of B-cell lymphomas, characterized by slow growth, protracted course without treatment and a tendency to reoccur after therapy. The management of ind-LYM is varied and evolving. To-date reliable tools for imaging based prognostication and treatment strategies are limited. We explored the utility of serial FDG PET scans (baseline (BL), interim/6 months (INT) end of therapy/1 year (EOT)), in managing ind-LYM). Methods: From an ongoing prospective study, examining the role of PET scan in ind-LYM at our institution, we performed an interim analysis of all patients hitherto enrolled in our study. Patients diagnosed as ind-LYM and having undergone serial PET scans from 2015 to date (N=40, males= 27, females =13) had median age of 59.68 ± 14.5 (28-82 at diagnosis. All PET scans were obtained per accepted protocols. SUVmax and Deauville scores (DS) were obtained from five target lesions. The average of composite SUV (cSUV) and composite Deauville scores (cDS) were computed for each patient. Statistical analyses (using t-test, mean delta change) were performed with the cSUV and cDS. Results: The types of ind-LYM were CLL/SLL (17), Follicular (15), mantle cell (3), marginal zone lymphoma (3), and 1 each of MALT and lymphoplasmacytic lymphoma. The data were analyzed for two arms of the study treatment chemotherapy arm (CHEMO-22/40) and Rituximab + observation arm (OBSR-18/40). At BL, patients on CHEMO had significantly higher cSUV and cDS compared to those who were on OBSR (SUV: 6.99 vs. 4.32 p-value 0.0124; cDS: 4.37 vs 3.71 p-value 0.0075 respectively). Although there was a delta change in the cSUV and cDS in both arms after INT and EOT, both treatment lines showed no significant difference in the SUV mean and DS (p-value: 0.754 and 0.5721, receptively). A 2-tailed T-test was used for delta change of cSUV. BL to INT cSUV was statistically significant (p-valve 0.05) and difference in cSUV was not significant for BL to EOT (p-valve 0.98). Difference in cDS was not significant between BL, INT and EOT. Conclusion: The higher cSUV/cDS at BL for the treatment arm may be due to disease profile at the time of presentation and/or selection bias. At EOT no difference in both estimates were noted. Both arms showed similar trends in delta change from BL-INT-EOT. Our findings suggest that SUV and DS at BL maybe an independent criterion for treatment selection in ind-LYM. Disclosures No relevant conflicts of interest to declare.

BACKGROUND The role of fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied. OBJECTIVE This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma. METHODS We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months. RESULTS SUVmax &lt;4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (<i>P</i>=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax &lt;4.35, versus 58.4% for SUVmax ≥4.35 (<i>P</i>=.13). The overall survival of patients with a baseline DC score &lt;3.0 was 100%, with a median overall survival of 106.67 months. CONCLUSIONS We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (&lt;4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS. CLINICALTRIAL

Introduction: Baseline (PETb) and end of therapy (PETe) FDG PET is standard of care in the management of hodgkin's lymphoma (HL) and diffuse large B cell lymphoma (DLBCL). The role of interim PET (PETi) in HL is well established while its role in DLBCL is not well defined. We evaluated the utility of triPET (PETb, PETi and PETe ) in management of these two lymphomas. Methods: Retrospective review of PET archives revealed a total of 37 pts (HL=22, DLBCL=15). TriPET were acquired per accepted protocol. SUVmax and Deauville scores (DSc) were obtained from five target lesions, the average i.e. composite SUVmax & DSc were computed for each pt. Statistical analyses were performed with the composite maxSUV (cSUV) and Deauville scores (cDSc) (using EXCEL). Following statistics were performed (separately and combined in HL and DLBCL); mean+SD, PPV and NPV for complete response (CR) Vs. progressive disease (PD) on PETi using the following variables 1. cSUV and 2. cDSc and 3. delta change (DELT). Median progression free survival (PFS) was the clinical endpoint for response. Results: The mean PFS in our group was 17 and 15 months in HL and DLBCL respectively. Using cut off thresholds for intP to predict CR at cSUV<=2.0, , cDSC<=2.0 and DELT >=80%,. In HL: for cSUV- PPV 67%, NPV 95%; for DELT of cSUV PPV 100%, NPV 95%; for cDSC-PPV 30%, NPV 100%. In DLBCL: for cSUV- PPV 25%, NPV 100%; for DELT of cSUV PPV 33%, NPV 100%; for cDSC- PPV 50%, NPV 100%. Conclusion: The results from our series suggest that PETi has a role not only in HL but in DLBCL as well. Our modest cohort suggests that a negative PETi in DLBCL had a NPV of 100% across cSUV, cDSc and DELT, with regards to CR. Our data also suggests that PETe is not needed if PETi is -ve. While in HL subset, our results concur with results from other groups, this needs to be validated in a larger series. Disclosures No relevant conflicts of interest to declare.