An international confirmatory study of the prognostic value of early PET/CT in diffuse large B-cell lymphoma: comparison between Deauville criteria and ΔSUVmax

Quantitative Assessment of Interim PET/CT Could Have More Prognostic Relevance than Visual Assessment for Predicting Clinical Outcome of Extranodal Diffuse Large B Cell Lymphoma

BACKGROUND/AIM

The present study retrospectively investigated the predictive accuracy of interim positron emission tomography/computed tomography (iPET/CT) based on the Deauville 5-point scale (5-PS) and a quantitative SUV-based assessment in patients with extranodal (EN) diffuse large B cell lymphoma (DLBCL).

PATIENTS AND METHODS

The Deauville 5-PS and the SUVmax reduction (ΔSUVmax) assessment for interpreting the response to iPET/CT were used.

RESULTS

A total of 163 patients were enrolled in this study. With a median follow-up of 52.5 months, ΔSUVmax successfully predicted the survival outcomes of patients with one extranodal (EN) involvement in terms of overall survival (OS) (p=0.012) and progression-free survival (PFS) (p<0.001). Visual assessment using the Deauville 5-PS did not predict survival outcomes in patients with one or more EN involvements in terms of OS and PFS.

CONCLUSION

The quantitative SUV-based assessment with iPET/CT was a significant prognosticator for long-term survival outcomes, especially in patients with one EN involvement.

Prognostic value of interim FDG-PET in diffuse large cell lymphoma: results from the CALGB 50303 Clinical Trial

As part of a randomized, prospective clinical trial in large cell lymphoma, we conducted serial fluorodeoxyglucose positron emission tomography (FDG-PET) at baseline, after 2 cycles of chemotherapy (interim PET [i-PET]), and at end of treatment (EoT) to identify biomarkers of response that are predictive of remission and survival. Scans were interpreted in a core laboratory by 2 imaging experts, using the visual Deauville 5-point scale (5-PS), and by calculating percent change in FDG uptake (change in standardized uptake value [ΔSUV]). Visual scores of 1 through 3 and ΔSUV ≥66% were prospectively defined as negative. Of 524 patients enrolled in the parent trial, 169 agreed to enroll in the PET substudy and 158 were eligible for final analysis. In this selected population, all had FDG-avid disease at baseline; by 5-PS, 55 (35%) remained positive on i-PET and 28 (18%) on EoT PET. Median ΔSUV on i-PET was 86.2%. With a median follow-up of 5 years, ΔSUV, as continuous variable, was associated with progression-free survival (PFS) (hazard ratio [HR] = 0.99; 95% confidence interval [CI], 0.97-1.00; P = .02) and overall survival (OS) (HR, 0.98; 95% CI, 0.97-0.99; P = .03). ΔSUV ≥66% was predictive of OS (HR, 0.31; 95% CI, 0.11-0.85; P = .02) but not PFS (HR, 0.47; 95% CI, 0.19-1.13; P = .09). Visual 5-PS on i-PET did not predict outcome. ΔSUV, but not visual analysis, on i-PET predicted OS in DLBCL, although the low number of events limited the statistical analysis. These data may help guide future clinical trials using PET response-adapted therapy. This trial was registered at www.clinicaltrials.gov as #NCT00118209.

Interim PET Evaluation in Diffuse Large B-Cell Lymphoma Using Published Recommendations: Comparison of the Deauville 5-Point Scale and the ΔSUVmax Method

The value of interim ¹⁸F-FDG PET/CT (iPET)-guided treatment decisions in patients with diffuse large B-cell lymphoma (DLBCL) has been the subject of much debate. This investigation focuses on a comparison of the Deauville score and the change-in-SUV_max (ΔSUV_max) approach-2 methods to assess early metabolic response to standard chemotherapy in DLBCL. Methods: Of 609 DLBCL patients participating in the PET-Guided Therapy of Aggressive Non-Hodgkin Lymphomas trial, iPET scans of 596 patients originally evaluated using the ΔSUV_max method were available for post hoc assessment of the Deauville score. A commonly used definition of an unfavorable iPET result according to the Deauville score is an uptake greater than that of the liver, whereas an unfavorable iPET scan with regard to the ΔSUV_max approach is characterized as a relative reduction of the SUV_max between baseline and iPET staging of less than or equal to 66%. We investigated the 2 methods' correlation and concordance by Spearman rank correlation coefficient and the agreement in classification, respectively. We further used Kaplan-Meier curves and Cox regression to assess differences in survival between patient subgroups defined by the prespecified cutoffs. Time-dependent receiver-operating-characteristic curve analysis provided information on the methods' respective discrimination performance. Results: Deauville score and ΔSUV_max approach differed in their iPET-based prognosis. The ΔSUV_max approach outperformed the Deauville score in terms of discrimination performance-most likely because of a high number of false-positive decisions by the Deauville score. Cutoff-independent discrimination performance remained low for both methods, but cutoff-related analyses showed promising results. Both favored the ΔSUV_max approach, for example, for the segregation by iPET response, where the event-free survival hazard ratio was 3.14 (95% confidence interval, 2.22-4.46) for ΔSUV_max and 1.70 (95% confidence interval, 1.29-2.24) for the Deauville score. Conclusion: When considering treatment intensification, the currently used Deauville score cutoff of an uptake above that of the liver seems to be inappropriate and associated with potential harm for DLBCL patients. The ΔSUV_max criterion of a relative reduction in SUV_max of less than or equal to 66% should be considered as an alternative.

Phase I study of CC-90010, a reversible, oral BET inhibitor in patients with advanced solid tumors and relapsed/refractory non-Hodgkin's lymphoma

BACKGROUND

Bromodomain and extra-terminal (BET) proteins are epigenetic readers that regulate expression of genes involved in oncogenesis. CC-90010 is a novel, oral, reversible, small-molecule BET inhibitor.

PATIENTS AND METHODS

CC-90010-ST-001 (NCT03220347; 2015-004371-79) is a phase I dose-escalation and expansion study of CC-90010 in patients with advanced or unresectable solid tumors and relapsed/refractory (R/R) non-Hodgkin's lymphoma (NHL). We report results from the dose escalation phase, which explored 11 dose levels and four dosing schedules, two weekly (2 days on/5 days off; 3 days on/4 days off), one biweekly (3 days on/11 days off), and one monthly (4 days on/24 days off). The primary objectives were to determine the safety, maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) and schedule. Secondary objectives were to evaluate signals of early antitumor activity, pharmacokinetics, and pharmacodynamics.

RESULTS

This study enrolled 69 patients, 67 with solid tumors and two with diffuse large B-cell lymphoma (DLBCL). The median age was 57 years (range, 21-80) and the median number of prior regimens was four (range, 1-9). Treatment-related adverse events (TRAEs) were mostly mild and manageable; grade 3/4 TRAEs reported in more than two patients were thrombocytopenia (13%), anemia, and fatigue (4% each). Six patients had dose-limiting toxicities. MTDs were 15 mg (2 days on/5 days off), 30 mg (3 days on/11 days off), and 45 mg (4 days on/24 days off). The RP2D and schedule selected for expansion was 45 mg (4 days on/24 days off). As of 8 October 2019, one patient with grade 2 astrocytoma achieved a complete response, one patient with endometrial carcinoma had a partial response, and six patients had prolonged stable disease ≥11 months.

CONCLUSIONS

CC-90010 is well tolerated, with single-agent activity in patients with heavily pretreated, advanced solid tumors.

SAKK38/07 study: integration of baseline metabolic heterogeneity and metabolic tumor volume in DLBCL prognostic model

Several functional parameters from baseline (18)F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography have been proposed as promising biomarkers of treatment efficacy in diffuse large B-cell lymphoma (DLBCL). We tested their ability to predict outcome in 2 cohorts of DLBCL patients receiving conventional immunochemotherapy (rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone [R-CHOP] regimen), either every 14 (R-CHOP14) or 21 days (R-CHOP21). Baseline PET analysis was performed in 141 patients with DLBCL treated with R-CHOP14 in the prospective SAKK38/07 study (NCT00544219) of the Swiss Group for Clinical Cancer Research (testing set). Reproducibility was examined in a validation set of 113 patients treated with R-CHOP21. In the SAKK38/07 cohort, progression-free survival (PFS) at 5 years was 83% for patients with low metabolic tumor volume (MTV) and 59% for those with high MTV (hazard ratio [HR], 3.4; 95% confidence interval [CI], 1.6-7.0; P = .0005), whereas overall survival (OS) was 91% and 64%, respectively (HR, 4.4; 95% CI, 1.9-10; P = .0001). MTV was the most powerful predictor of outcome also in the validation set. Elevated metabolic heterogeneity (MH) significantly predicted poorer outcomes in the subgroups of patients with elevated MTV. A model integrating MTV and MH identified high-risk patients with shorter PFS (testing set: HR, 5.6; 95% CI, 1.8-17; P < .0001; validation set: HR, 5.6; 95% CI, 1.7-18; P = .0002) and shorter OS (testing set: HR, 9.5; 95% CI, 1.7-52; P < .0001; validation set: HR, 7.6; 95% CI, 2.0-28; P = .0003). This finding was confirmed by an unsupervised regression tree analysis indicating that prognostic models based on MTV and MH may allow early identification of refractory patients who might benefit from treatment intensification. This trial was registered at www.clinicaltrials.gov as #NCT00544219.

Prognostic Value of Baseline Total Metabolic Tumor Volume Measured on FDG PET in Patients With Richter Syndrome

PURPOSE

We evaluated the prognostic value of baseline total metabolic tumor volume (TMTV) measured using pretreatment FDG PET for patients with transformation of chronic lymphocytic leukemia (CLL) into diffuse large B-cell lymphoma (DLBCL).

METHODS

A total of 28 patients with transformation of CLL into DLBCL who had undergone FDG PET before treatment were retrospectively reviewed. Univariate and multivariate analysis of conventional clinicopathologic variables (sex, age, World Health Organization performance status score, International Prognostic Index score, Binet stage, lactate dehydrogenase serum level [LDH], platelet count, presence or not of prior therapies for CLL, the time from CLL to Richter syndrome, Ann Arbor stage, Bulky or not) and metabolic parameters (SUVmax, SUVmean, TMTV, and total lesion glycolysis) at the time of the transformation of CLL into DLBCL were tested for overall survival (OS).

RESULTS

Of the 28 patients, 14 patients (50%) died during the follow-up period. Low platelet count, World Health Organization performance status score >1, high LDH, and high TMTV were found to be significant prognostic factors for OS on univariate analysis. The 5-year estimates of OS were 63% in the low metabolic burden group (TMTV ≤1200 cm) and 0% in the high metabolic burden group (TMTV >1200 cm). Multivariate analysis revealed that only high LDH was a significant predictor after adjustment for other variables of OS.

CONCLUSIONS

TMTV extracted from FDG PET at the time of the transformation of CLL into DLBCL is a predictor of OS.

FDG-PET Imaging for Hodgkin and Diffuse Large B-Cell Lymphoma-An Updated Overview

Since the mid-1990s, ¹⁸F-fluorodeoxglucose (FDG)-positron emission tomography (PET) in combination with computed tomography has come to play a prominent role in the management of malignant lymphomas. One of the first PET applications in oncology was the detection of lymphoma manifestations at staging, where it has shown high sensitivity. Nowadays, this imaging modality is also used during treatment to evaluate the individual chemosensitivity and adapt further therapy accordingly. If the end-of-treatment PET is negative, irradiation in advanced-stage Hodgkin lymphoma patients can be safely omitted after highly effective chemotherapy. Thus far, lymphoma response assessment has mainly been performed using visual criteria, such as the Deauville five-point scale, which became the international standard in 2014. However, novel measures such as metabolic tumor volume or total lesion glycolysis have recently been recognized by several working groups and may further increase the diagnostic and prognostic value of FDG-PET in the future.

Prognostic impact of interim positron emission tomography in mantle cell lymphoma patients treated with frontline R-CHOP

Although ¹⁸F‐fluorodeoxyglucose positron emission tomography (¹⁸F‐FDG PET) is commonly used for initial staging and therapeutic response evaluation in aggressive lymphomas, its prognostic utility for mantle cell lymphoma (MCL) is controversial. Therefore, we retrospectively evaluated the correlations of interim PET (iPET) and end‐of‐treatment PET (ePET) response with survival outcomes in 89 consecutive advanced MCL patients treated with frontline R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone). iPET positivity was strongly associated with inferior five‐year overall survival (OS) [hazard ratio (HR) 7·84, P < 0·0001] and poor five‐year progression‐free survival (PFS) (HR 3·34, P < 0·0001). OS and PFS were more favourable in the order early metabolic responder (iPET^neg → ePET^neg), delayed responder (iPET^pos → ePET^neg), loss‐metabolic responder (iPET^neg → ePET^pos), and never‐metabolic responder (iPET^pos → ePET^pos). In the autologous haematopoietic stem cell transplantation (auto‐HSCT)‐fit subgroup, OS was more favourable in the order early metabolic responders, delayed metabolic responders, and non‐metabolic responders, with a marginal trend toward statistical significance (HR 3·41, P = 0·051), and PFS was significantly superior in early metabolic responders (HR 4·43, P = 0·002). In a group that was ineligible for auto‐HSCT, OS and PFS were significantly superior in early metabolic responders. Our results suggested that iPET is of prognostic value and an independent predictor of survival in MCL patients receiving frontline R‐CHOP. Therefore, prospective clinical trials of iPET‐guided treatment strategies for these patients are warranted.

Risk Stratification Of Diffuse Large B-Cell Lymphoma With Interim PET/CT By Combining Deauville Scores And International Prognostic Index

Purpose

Prognostic evaluation using interim positron emission tomography/computed tomography (interim PET/CT; I-PET) remains controversial. For any predictor, the prognosis of patients around its cutoff value is most uncertain. If the patients around the cutoff value could be subdivided by another factor, like the international prognostic index (IPI), it may improve the predictive power of I-PET. The combination of I-PET and IPI for risk stratification of patients was explored in this study.

Patients and methods

One hundred and eleven diffuse large B-cell lymphoma (DLBCL) patients treated with R-CHOP therapy were included retrospectively, 59 of whom underwent PET/CT after three or four cycles of treatment (I-PET). Fifty-two patients underwent PET/CT after five or six cycles of treatment (end of treatment; E-PET).

Results

When Deauville 5-point scale (5-DS) scores of 4–5 were classified as a positive scan (denoted by DS [score 4]), there was no significant difference in progression-free survival (PFS) between I-PET positive and negative patients (P=0.151). Further, patients with 5-DS score 3 and high IPI were stratified into I-PET positive-, whereas those with 5-DS score 3 and low IPI were classified into I-PET negative scan groups. Under this stratification, there was a significant difference in PFS between I-PET positive and negative patients (P=0.001). The sensitivity, positive predictive value, and negative predictive value for 2-year PFS for the combination score were higher than DS (score 4) alone (66.7% vs 33.3%, 50.0%vs 37.5%, 93.6% vs 88.2%) whereas specificity was almost the same (90.0% vs 88.0%).

Conclusion

Subdivision of patients with 5-DS score 3 by IPI improved prognostic prediction accuracy. The IPI adds strength to 5-DS in I-PET to detect patients with good or poor prognosis. Compared with other combinations of I-PET and IPI, dividing the patients around the cutoff value of 5-DS by IPI was easily accepted by clinicians and allowed them to decide on further treatment practically.

Predictive value of interim FDG-PET/CT findings in patients with diffuse large B-cell lymphoma treated with R-CHOP

Objectives: To examine the prognostic value of interim 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) findings after 2–4 cycles of rituximab, plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in patients with diffuse large B-cell lymphoma (DLBCL) receiving standardized treatment.

Results: After a median 3.36 years (range 0.33 to 9.14 years), 24 of the 80 patients had documented relapse. In Interim-PET findings, 2-year PFS was significantly shorter for PET-positive as compared with PET-negative patients (50.0% vs. 86.4%; p = 0.0012). In End-PET findings, 2-year PFS was significantly shorter for PET-positive as compared with PET-negative patients (25.0% vs. 84.7%; p < 0.0001). The positive predictive value (PPV) and negative predictive value (NPV) of Interim-PET for predicting relapse or disease progression were 57.1% and 75.8%, respectively, while those for End-PET were 75.0% and 75.0%, respectively.

Methods: Eighty DLBCL patients treated with first-line 6–8 R-CHOP courses regardless of interim imaging findings were enrolled. Each underwent FDG-PET/CT scanning at staging, and again during (Interim-PET) and at the end of (End-PET) therapy. PET positivity or negativity at Interim-PET and End-PET as related to progression-free survival (PFS) was examined using Kaplan–Meier analysis.

Conclusion: Mid-treatment FDG-PET/CT findings may be useful for determining disease status in patients with DLBCL undergoing induction R-CHOP chemotherapy, though are not recommended for treatment decisions as part of routine clinical practice.

Prognostic Value of Pre-Autologous Stem Cell Transplantation PET/CT in Diffuse Large B-Cell Lymphoma: The Deauville Score Is Prognostically Superior to ΔSUVmax

OBJECTIVE

The predictive value of pre-autologous stem cell transplantation (pre-ASCT) positron emission tomography/computed tomography (PET/CT) scans according to different criteria remains elusive in patients with diffuse large B-cell lymphoma (DLBCL).

METHODS

A total of 46 DLBCL patients treated with pre-ASCT were enrolled in the present study, and two methods, Deauville score and maximal standardized uptake value reduction (ΔSUVmax), were used to evaluate the PET/CT scans before transplantation.

RESULTS

In patients with Deauville 1-3 and ≥4, the 2-year progression-free survival (PFS) rates were 82.8 and 11.8% (p < 0.001), respectively, while the 2-year overall survival (OS) rates were 89.7 and 41.2%, respectively (p < 0.001). When using the ΔSUVmax cut-off of 66% criterion, in patients with a ΔSUVmax of >66 and ≤66%, the 2-year PFS rates were 78.1 and 7.1%, respectively (p < 0.001), while the 2-year OS rates were 87.5 and 35.7%, respectively (p < 0.001). In the univariate analysis, the ΔSUVmax, Deauville score, NCCN-IPI and serum lactate dehydrogenase levels were significantly correlated with the 2-year PFS/OS. Furthermore, the multivariate analysis revealed that the Deauville score was an independent prognostic factor for 2-year PFS.

CONCLUSION

The present results indicate that PET/CT scans at pre-ASCT can predict the survival of DLBCL patients, and the Deauville score is better than ΔSUVmax in prognostic prediction.

Interim PET/CT based on visual and semiquantitative analysis predicts survival in patients with diffuse large B-cell lymphoma

Purpose

The role of interim ¹⁸F‐FDG PET/CT (iPET/CT) in diffuse large B‐cell lymphoma (DLBCL) remains controversial. The purpose of this study was to assess the prognostic value of iPET/CT in patients with newly diagnosed DLBCL according to visual and semiquantitative interpretation methods.

Methods

A total of 129 newly diagnosed DLBCL patients with baseline PET/CT data were retrospectively screened. The iPET/CT findings were evaluated by the Deauville 5‐point scale (DS) and ΔSUVmax. Furthermore, the reduction in SUVmax incorporated with tumor size (ΔSUVmax*ΔSLD) was calculated. The optimal cutoff values of ΔSUVmax and ΔSUVmax*ΔSLD were determined by receiver operating characteristic (ROC) analysis. Kaplan‐Meier analysis was applied to test for the influence of prognostic values. Univariate and multivariate analyses were conducted to examine the potential independent impacts of iPET/CT.

Results

Seventy‐seven patients with PET/CT images acquired both at baseline and after four cycles of chemotherapy were finally enrolled. The optimal cutoff values for ΔSUVmax and ΔSUVmax*ΔSLD were 74% and 30%, respectively. After a median follow‐up of 23 months, iPET/CT findings were significant predictors of PFS and OS whenever iPET/CT was interpreted by DS, ΔSUVmax, or ΔSUVmax*ΔSLD methods. ΔSUVmax‐based methods were more accurate than those based on DS. The IPI, DS, ΔSUVmax, and ΔSUVmax*ΔSLD were predictive in univariate analyses. However, in the multivariate analysis, only IPI and ΔSUVmax remained independent predictors of PFS and OS.

Conclusions

Interim PET/CT may help to identify DLBCL patients with different prognoses. ΔSUVmax analysis shows the best accuracy and the strongest predictive value among these three methods. ΔSUVmax*ΔSLD may be a promising parameter to interpret iPET/CT images, reflecting both the changes in tumor size and metabolic activity.

Predictive Value of Interim and End-of-Therapy 18F-FDG PET/CT in Patients with Follicular Lymphoma

Purpose

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is the standard imaging modality for response evaluation in FDG-avid lymphoma, but the prognostic value is not established in follicular lymphoma (FL). This study investigated the prognostic value of Deauville 5-point scale (D5PS) from paired interim PET/CT (PET_Interim) and end-of-induction therapy PET/CT (PET_EOI) in patients with FL.

Methods

FL staging and response assessment PET/CT images from 2013 to 2015 were retrospectively reviewed. PET_Interim was performed 3 or 4 cycles after chemotherapy and PET_EOI after 6 or 8 cycles. D5PS scores of 1, 2, and 3 were considered as negative (-), and scores 4 and 5 were considered as positive (+). Statistical analysis was done using Cox regression analysis, Kaplan-Meier survival analysis, and the log-rank test.

Results

Thirty-three patients with set of baseline, interim, and end-of-induction therapy PET/CT studies were included. Ten patients (30.3%) had progression. The median progression-free survival (PFS) was 38.8 months (range 3.5-72.7 months). On PET_Interim, 23 patients were negative and 10 were positive. On PET_EOI scans, 29 patients were negative, and 4 were positive. On multivariate analysis, PET_EOI(-) was associated with longer PFS. PET_Interim(+) and PET_EOI(+) patients had a significantly shorter PFS than PET_Interim(-) patients (39.9 months, 95% confidence interval [CI] 23.0-56.9, versus 55.5 months, 95% CI 49.7-61.2, p = 0.005) and PET_EOI(-) patients (14.2 months, 95% CI 8.5-19.8, versus 60.5 months, 95% CI 52.1-69.0, p < 0.001).

Conclusion

For patients with FL, PET_Interim and PET_EOI response is predictive of PFS, and PET_EOI(+) is an independent prognostic factor for progression of FL.

End-of-Treatment PET/Computed Tomography Response in Diffuse Large B-Cell Lymphoma

"PET imaging with fluorodeoxyglucose (FDG), integrated with PET/computed tomography (FDG-PET/CT), is an effective management tool of diffuse large B-cell lymphoma (DLBCL). The results of end-of-treatment (EOT) FDG-PET/CT are more accurate for detection of active disease with residual masses on CT. Complete response defined by EOT FDG-PET/CT (PET-CR) correlates with long-term outcome of patients. Treatment efficacy is determined using EOT PET/CT rather than progression-free survival (PFS) for clinical trials assessing novel drugs. If the correlation of EOT PET/CT with PFS is further proven in large studies and meta-analyses, EOT PET-CR could serve as an expedited novel endpoint replacing PFS."

Time to Prepare for Risk Adaptation in Lymphoma by Standardizing Measurement of Metabolic Tumor Burden

Increased tumor burden is associated with inferior outcomes in many lymphoma subtypes. Surrogates of tumor burden that are easy to measure, such as the maximum tumor dimension of the bulkiest lesion on CT, have been used as prognostic indices for many years. Recently, total metabolic tumor volume (MTV) and tumor lesion glycolysis have emerged as promising and robust biomarkers of outcome in various lymphomas. The median MTV and the optimal cutoffs to separate patients into risk groups in a study population are, however, highly dependent on the population characteristics and the delineation method used to outline tumor on the PET image. This issue has precluded the use of MTV for risk stratification in trials and clinical practice. Standardization of the methodology is timely to allow the potential for risk adaptation to be explored in addition to response adaptation using PET. Meetings between representatives from research groups active in the field were held under the auspices of the PET International Lymphoma and Myeloma Workshop. A summary of those discussions, which included a review of the literature and a practical assessment of methods used for outlining, including various software options, is presented. Finally, a proposal is made to perform a technical validation of MTV measurement enabling benchmark reference ranges to be derived for published delineation approaches used for outlining with various software. This process would require collation of representative imaging data sets of the most common lymphoma subtypes; agreement on pragmatic criteria for the selection of lesions; generation of a range of MTVs, with consensus to be reached on final contours in a training set; and development of automated software solutions with a set of minimum functionalities to reduce measurement variability. Methods developed in the above training exercise could then be applied to another data set, with a final set of contours and values generated. This final data set would provide a benchmark against which end-users could test their ability to measure MTVs that are consistent with expected values. The data set and automated software solutions could be shared with manufacturers with the aim of including these in standard workflows to allow standardization of MTV measurement across the world.

[Prognostic significance of (18)F-fluorodeoxyglucose positron emission tomography in patients with diffuse large B cell lymphoma undergoing autologous stem cell transplantation]

Objective: To evaluate the prognostic value of (18)F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) in patients with diffuse large B cell lymphoma (DLBCL) undergoing autologous hematopoietic stem cell transplantation (auto-HSCT). Methods: Forty-eight patients with DLBCL treated at Peking University Cancer Hospital between November 2010 and December 2014 were assessed. All patients underwent PET/CT scanning prior to or after auto-HSCT. Correlation analysis was done based upon patients characteristics, PET/CT scan results and survival. Results: ①Among 48 patients, 27 was male, 21 female, median age was 43 (17-59) years old. ② Patients with negative pre-auto-HSCT PET/CT assessment demonstrated significantly better 3-year progression free survival (PFS) (87.1% vs 53.3%, χ(2)=7.02, P=0.019) and overall survival (OS) (90.3% vs 60.0%, χ(2)=6.51,P=0.022) than patients with positive pre-auto-HSCT PET/CT assessment. Three-year PFS (94.1% vs 30.0%, χ(2)=22.75, P=0.001) and OS (97.1% vs 40.0%, χ(2)=21.09, P=0.002) were also significantly different between patients with negative and positive post-auto-HSCT PET/CT assessment. ③ Multivariate analysis indicated a significant association of PFS (HR=13.176, P=0.005) and OS (HR=20.221, P=0.007) with post-auto-HSCT PET/CT assessment. Number of prior treatment regimens was associated with PFS (HR=10.039, P=0.040). ④ Harrell's C index revealed that the value of combined use of number of prior treatment regimens and post-auto-HSCT PET/CT assessment was superior to either one used alone in PFS (Harrell's C values were 0.976, 0.869 and 0.927 in combined use, number of prior treatment regimens and post-auto-HSCT PET/CT assessment, respectively), and the combined use of ECOG performance status and post-auto-HSCT PET/CT assessment significantly increased the Harrell's C index in OS (Harrell's C values were 0.973, 0.711 and 0.919 in combined use, ECOG performance status and post-auto-HSCT PET/CT assessment, respectively). Conclusions: Post-auto-HSCT PET/CT assessment is the main predictor of outcomes in DLBCL patients receiving auto-HSCT. Combined use of post-auto-HSCT PET/CT assessment and number of prior treatment regimens and ECOG performance status is a better prognostic tool in patients with DLBCL undergoing transplantation.

Comparison of therapeutic evaluation criteria in FDG-PET/CT in patients with diffuse large-cell B-cell lymphoma: Prognostic impact of tumor/liver ratio

PURPOSE

The study objective was to compare the prognostic value of interim and end-of-treatment FDG PET/CT using five therapeutic evaluation criteria in patients with diffuse large B cell lymphoma (DLBCL).

METHODS

181 patients were retrospectively analysed. All patients underwent FDG-PET at baseline and after four cycles (iPET4) of first-line chemotherapy and 165 at the end-of-treatment (PET-eot). Ratio Deauville score (rDS) (SUVmax-target residual lesion/SUVmax-liver) was measured in iPET4 and PET-eot, and its optimal threshold was determined using receiver operating characteristic (ROC) curve analysis. Deauville score (DS) (iPET4 and PET-eot), ΔSUVmax, ΔSUVmax determined according to Menton 2011 criteria (ΔSUVmax+DS) and ΔSUVmax+rDS were also evaluated (iPET4 only). Median follow-up was 44 months.

RESULTS

ROC analysis revealed the optimal cut-off value was 1.4-fold of SUVmax-liver on iPET4 and PET-eot. On iPET4, positive predictive value (PPV) of rDS was significantly better than DS: 81.58% vs. 67.79%. In univariate analysis, the five interpretation methods were statistically significant (p<0.0001 for progression-free survival [PFS] and overall survival [OS]). In multivariate analysis, only rDS was an independent prognostic factor (p = 0.0002 and p<0.0001 for PFS and OS, respectively). On PET-eot, similarly, the two therapeutic evaluation criteria analysed (rDS and DS) were statistically significant at the univariate level (p<0.0001). rDS was the only significant prognostic factor in multivariate analysis (p<0.0001). PPV and accuracy of rDS were also better than DS.

CONCLUSIONS

rDS with a tumor/liver ratio of 1.4 is a robust prognostic factor in patients with DLBCL on iPET4 and PET-eot.

Prognostic analysis of interim 18F-FDG PET/CT in patients with diffuse large B cell lymphoma after one cycle versus two cycles of chemotherapy

Objectives

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is routinely used in diffuse large B cell lymphoma (DLBCL) for staging, assessment of remission and recurrence, and estimation of therapeutic efficacy. In this study, we aimed to assess the role of an early interim PET/computed tomography (CT) in the evaluation of response in DLBCL.

Methods

Sixty primary DLBCL patients (31 females) were analyzed. Baseline and follow-up ¹⁸F-FDG PET/CT was performed in patients after one cycle (n = 30) and two cycles (n = 30) of chemotherapy. The ΔSUVmax% was calculated. Patients were additionally evaluated using the conventional Deauville five-point scale (D-5PS) system. Fluorescence in situ hybridization (FISH) was employed to characterize the MYC gene status. We determined the optimum cutoff value of ΔSUVmax% using receiver operating characteristic (ROC) analysis. Kaplan–Meier analysis was applied to test for the influence of prognostic values.

Results

The optimal cutoff for the prediction of treatment outcome was a ΔSUVmax% of 57% (after one cycle) and 63% (after two cycles); we could not detect a difference in accuracy with respect to a PET scan performed after one cycle and two cycles of chemotherapy (P  > 0.05). The ΔSUVmax% and the D-5PS (score 5) showed the highest prognostic value compared to a score of 3 and/or 4 (both after one cycle and two cycles). No significant difference in sensitivity, specificity, accuracy, or the area of under the curve (AUC) of ΔSUVmax% and D-5PS (score 5) was observed between PETs performed after one cycle or two cycles of therapy (P  > 0.05). ΔSUVmax%, D-5PS (score 5), and MYC gene rearrangement correlated significantly (P  < 0.001).

Conclusion

Interim ¹⁸F-FDG PET/CT after one cycle of chemotherapy is feasible and yields similar predictive results as compared to an interim ¹⁸F-FDG PET/CT after two cycles of chemotherapy in patients suffering from DLBCL. The combination of interim ¹⁸F-FDG PET/CT with the MYC gene diagnosis might provide increased prognostic value for DLBCL.

Automated quantification of reference levels in liver and mediastinal blood pool for the Deauville therapy response classification using FDG-PET/CT in Hodgkin and non-Hodgkin lymphomas

BACKGROUND

18F-FDG-PET/CT has become a standard for assessing treatment response in patients with lymphoma. A subjective interpretation of the scan based on the Deauville 5-point scale has been widely adopted. However, inter-observer variability due to the subjectivity of the interpretation is a limitation. Our main goal is to develop an objective and automated method for evaluating response. The first step is to develop and validate an artificial intelligence (AI)-based method, for the automated quantification of reference levels in the liver and mediastinal blood pool in patients with lymphoma.

METHODS

The AI-based method was trained to segment the liver and the mediastinal blood pool in CT images from 80 lymphoma patients, who had undergone 18F-FDG-PET/CT, and apply this to a validation group of six lymphoma patients. CT segmentations were transferred to the PET images to obtain automatic standardized uptake values (SUV). The AI-based analysis was compared to corresponding manual segmentations performed by two radiologists.

RESULTS

The mean difference for the comparison between the AI-based liver SUV quantifications and those of the two radiologists in the validation group was 0·02 and 0·02, respectively, and 0·02 and 0·02 for mediastinal blood pool respectively.

CONCLUSIONS

An AI-based method for the automated quantification of reference levels in the liver and mediastinal blood pool shows good agreement with results obtained by experienced radiologists who had manually segmented the CT images. This is a first, promising step towards objective treatment response evaluation in patients with lymphoma based on 18F-FDG-PET/CT.

Prognostic role of baseline 18F-FDG PET/CT metabolic parameters in Burkitt lymphoma

PURPOSE

Burkitt's lymphoma (BL) is an aggressive lymphoma subtype with high 18F-FDG avidity at 18F-FDG-PET/CT, but no validated criteria for PET/CT in treatment evaluation or prediction of outcome in BL are available. The aim of our study was to investigate whether the metabolic baseline PET/CT parameters can predict treatment response and prognosis in BL.

MATERIALS AND METHODS

We retrospectively enrolled 65 patients who underwent baseline 18F-FDG-PET/CT, interim and end of treatment PET/CT. The PET images were analyzed visually and semi-quantitatively by measuring the maximum standardized uptake value body weight (SUVbw), the maximum standardized uptake value lean body mass (SUVlbm), the maximum standardized uptake value body surface area (SUVbsa), lesion to liver SUVmax ratio (L-L SUV R), lesion to blood-pool SUVmax ratio (L-BP SUV R), total metabolic tumor volume (tMTV) and total lesion glycolysis (TLG). Survival curves were plotted according to the Kaplan-Meier method.

RESULTS

At a median follow-up of 40 months, the median PFS and OS were 34 and 39 months. MTV and TLG were significantly higher in patients with partial response compared to complete response group at end of treatment, while no significant differences were found at interim. Other metabolic PET/CT parameters were not related to treatment response. MTV and TLG were demonstrated to be independent prognostic factors for both PFS and OS; instead SUVbw, SUVlbm, SUVbsa, L-L SUV R and L-BP SUV R were not related to outcome survival.

CONCLUSIONS

Metabolic tumour features (MTV and TLG) were significantly correlated with response to treatment and long-term outcome.

Predictive value of interim positron emission tomography in diffuse large B-cell lymphoma: a systematic review and meta-analysis

Purpose

Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of non-Hodgkin lymphoma. Most relapses occur in the first 2 years after diagnosis. Early response assessment with ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography (PET) may facilitate early change of treatment, thereby preventing ineffective treatment and unnecessary side effects. We aimed to assess the predictive value of visually-assessed interim ¹⁸F-FDG PET on progression-free survival (PFS) or event-free survival (EFS) in DLBCL patients treated with first-line immuno-chemotherapy regimens.

Methods

For this systematic review and meta-analysis Pubmed, Embase, and the Cochrane Library were searched until July 11, 2017. Prospective and retrospective studies investigating qualitative interim PET response assessment without treatment adaptation based on the interim PET result were eligible. The primary outcome was two-year PFS or EFS. Prognostic and diagnostic measures were extracted and analysed with pooled hazard ratios and Hierarchical Summary Receiver Operator Characteristic Curves, respectively. Meta-regression was used to study covariate effects.

Results

The pooled hazard ratio for 18 studies comprising 2,255 patients was 3.13 (95%CI 2.52–3.89) with a 95% prediction interval of 1.68–5.83. In 19 studies with 2,366 patients, the negative predictive value for progression generally exceeded 80% (64–95), but sensitivity (33–87), specificity (49–94), and positive predictive values (20–74) ranged widely.

Conclusions

These findings showed that interim ¹⁸F-FDG PET has predictive value in DLBCL patients. However, (subgroup) analyses were limited by lack of information and small sample sizes. Some diagnostic test characteristics were not satisfactory, especially the positive predictive value should be improved, before a successful risk stratified treatment approach can be implemented in clinical practice.

Electronic supplementary material

The online version of this article (10.1007/s00259-018-4103-3) contains supplementary material, which is available to authorized users.

Optimizing initial therapy in DLBCL

Diffuse large B-cell lymphoma (DLBCL) is a group of lymphomas comprising heterogeneous molecular and biological subtypes, reflected in a broad range of clinical outcomes. With the standard R-CHOP regimen of cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab administered every 21 days, the treatment failure rate remains unacceptably high in certain DLBCL subsets. Here we review possible avenues for optimizing initial therapy. The role of functional imaging and biological features, such as double-hit lymphomas, defined by the dual translocation of MYC and BCL2, and dual protein-expresser lymphomas, defined by the overexpression of MYC and BCL2, activated B-cell (ABC)-like DLBCL, to better define these high-risk patient subsets, and their use to guide and personalize treatment decisions are discussed. Secondly, the implications of varying dose-intensification of the various agents administered, and the link to imaging are reviewed. Thirdly, the results of the addition of novel drugs to standard R-CHOP will be analyzed, when added at induction or in maintenance. Finally, with CNS relapse in DLBCL representing a major and devastating unmet medical need, an overview and future directions for CNS prophylaxis is presented.

Interim PET Analysis in First-Line Therapy of Multiple Myeloma: Prognostic Value of ΔSUVmax in the FDG-Avid Patients of the IMAJEM Study

Purpose: To assess the prognostic value of interim ¹⁸F-fluorodeoxyglucose (FDG)-PET analysis using decrease in maximum standardized uptake value (SUVmax) versus visual analysis in patients with multiple myeloma.Patients and Methods: We evaluated the prognostic value of FDG-PET after three cycles of lenalidomide, bortezomib, and dexamethasone (RVD) in patients with FDG-avid multiple myeloma included in the French prospective multicenter IMAJEM study. All images were centrally reviewed and interpreted using visual criteria and maximal standardized uptake value reduction (ΔSUVmax). Known prognostic factors, such as the revised International Staging System and biochemical response after three cycles of chemotherapy, were also evaluated.Results: In the multivariate analysis, only ΔSUVmax [P < 0.001, HR = 5.56; 95% confidence interval (CI), 1.96-15.81] and biochemical response after three cycles of RVD (P = 0.025, HR = 0.29; 95% CI, 0.1-0.85) appeared as independent prognostic factors, with a more discriminative HR for ΔSUVmax. ΔSUVmax analysis (>-25% vs. ≤-25%) identified patients with improved median progression-free survival (22.6 months and not reached, respectively).Conclusions: ΔSUVmax appears to be a powerful tool for the prediction of long-term outcome in patients with FDG-avid multiple myeloma. Other prospective studies are needed to further validate this prognostic biomarker. Clin Cancer Res; 24(21); 5219-24. ©2018 AACR.

Non-invasive monitoring of diffuse large B-cell lymphoma by cell-free DNA high-throughput targeted sequencing: analysis of a prospective cohort

From a liquid biopsy, cell-free DNA (cfDNA) can provide information regarding basal tumoral genetic patterns and changes upon treatment. In a prospective cohort of 30 diffuse large B-cell lymphomas (DLBCL), we determined the clinical relevance of cfDNA using targeted next-generation sequencing and its correlation with PET scan imaging at the time of diagnosis and during treatment. Using a dedicated DLBCL panel, mutations were identified at baseline for 19 cfDNAs and profiles were consistent with expected DLBCL patterns. Tumor burden-related clinical and PET scan features (LDH, IPI, and metabolic tumor volume) were significantly correlated with the quantity of tumoral cfDNA. Among the four patients presenting additional mutations in their cfDNAs, three had high metabolic tumor volumes, suggesting that cfDNA more accurately reflects tumor heterogeneity than tissues biopsy itself. Mid-treatment, four patients still had basal mutations in their cfDNAs, including three in partial response according to their Deauville scores. Our study highlights the major interests in liquid biopsy, in particular in the context of bulky tumors where cfDNA allows capturing the entire tumoral mutation profile. Therefore, cfDNA analysis in DLBCL represents a complementary approach to PET scan imaging.

The Association Between Liver and Tumor [18F]FDG Uptake in Patients with Diffuse Large B Cell Lymphoma During Chemotherapy

PURPOSE

The aim of this study was to explore the association between liver, mediastinum and tumor 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) uptake during chemotherapy in diffuse large B cell lymphoma (DLBCL).

PROCEDURES

Nineteen patients with proven DLBCL underwent positron emission tomography (PET)/X-ray computed tomography scan at baseline, 1 week and 2 cycles after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy, and again after chemotherapy completion. The mean and maximal standardized uptake value (SUVmean and SUVmax) of the liver and mediastinum were measured and correlated with the tumor SUVmax, SUVsum, whole-body metabolic tumor volume (MTVwb), and total lesion glycolysis (TLG).

RESULTS

At baseline, both the liver and mediastinum SUVmean and SUVmax correlated inversely with the tumor MTVwb or TLG (p < 0.01 or 0.001). The liver SUVmean and SUVmax increased significantly after 1 week of R-CHOP therapy and remained at the high level until chemotherapy completion. The mediastinum SUVmean and SUVmax remained stable during chemotherapy. The tumor SUVmax, SUVsum, MTVwb, and TLG decreased significantly after 1 week of R-CHOP therapy. The change of the liver SUVmean correlated inversely with the change of tumor MTVwb and TLG after 1 week of chemotherapy (p < 0.05, respectively). The intersubject variability of liver and mediastinum [¹⁸F]FDG uptake ranged from 11 to 26 %.

CONCLUSIONS

The liver [¹⁸F]FDG uptake increased significantly after R-CHOP therapy. One of the possible reasons is the distribution of a greater fraction of the tracer to healthy tissues rather than tumor after effective chemotherapy. The variability of the liver [¹⁸F]FDG uptake during chemotherapy might affect the visual analysis of the interim PET scan and this needs to be confirmed in future studies with a large patient cohort. In addition, the intersubject variability of the liver and mediastinum [¹⁸F]FDG uptake should be considered.

Prognostic value of interim fluorodeoxyglucose and fluorothymidine PET/CT in diffuse large B-cell lymphoma

OBJECTIVE:

To examine the prognostic value of fluorodeoxyglucose (FDG) and fluorothymidine (FLT) interim positron emission tomography/CT (PET/CT) for diffuse large B-cell lymphoma (DLBCL).

METHODS:

44 patients with newly diagnosed DLBCL underwent both fluorine 18 FDG (¹⁸F-FDG) and ¹⁸F-FLT PET/CT scans at baseline and after two cycles of a rituximab-containing chemotherapy regimen. Maximum standard uptake values (SUV_max) and changes in SUV (ΔSUV) were calculated for both tracers for the predominant lesion of each patient, for prediction of progression-free survival (PFS) and overall survival (OS).

RESULTS:

The median follow-up period was 71 months. Receiver operating characteristic (ROC) analysis indicated that the best ΔSUV cut-off values for FDG (ΔSUV_FDG) and FLT (ΔSUV_FLT) were 79 and 76%, respectively. A ΔSUV_FLT cut-off of 76% had the highest significance for prediction of PFS (p = 0.003) and OS (p = 0009), with sensitivity, specificity, and accuracy of 80.0, 85.7, and 81.8% respectively in response assessment.

CONCLUSION:

Interim FLT PET/CT had higher specificity and accuracy than standard FDG PET/CT-based interpretation.

ADVANCES IN KNOWLEDGE:

This study demonstrated that interim FLT PET/CT had higher accuracy than standardized FDG-based interpretation for therapeutic response assessment in DLBCL. FLT had the advantage of potentially reducing false positive of interim FDG PET/CT.

Interim PET/CT Result Is Not Predictive of Survival in Patients With MYC-rearranged Non-Burkitt Aggressive B-cell Lymphoma

BACKGROUND

Patients with a diagnosis of MYC-rearranged non-Burkitt aggressive B-cell lymphoma (MYC-R), including those with double hit lymphoma, are at high risk of developing relapsed/refractory disease, even if treated with intensive front-line immunochemotherapy. It is common in clinical practice and clinical trials to perform an interim positron emission tomography (PET)/computed tomography (CT) scan (iPET) during front-line therapy for diffuse large B-cell lymphoma. However, the utility of the iPET result for MYC-R patients for predicting outcomes is unclear.

PATIENTS AND METHODS

We performed a single-center retrospective study with centralized pathologic review and PET/CT image acquisition and interpretation for 28 MYC-R patients. The patients received front-line therapy with R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin [doxorubicin], Oncovin [vincristine], prednisone) or intensive immunochemotherapy.

RESULTS

Eight patients had iPET-positive (iPET⁺) and 20 patients had iPET-negative (iPET^-) results using the Deauville visual assessment criteria. At a median follow-up length of 30.4 months, progression-free survival was 65% and overall survival was 76%, neither of which differed significantly between the iPET^- and iPET⁺ patients. The positive predictive value of iPET for progression at 30 months was 25%, and the negative predictive value was 65%.

CONCLUSION

Although patients with MYC-R lymphoma have been reported to be at high risk of primary treatment failure, this was not predicted by iPET⁺ results. Thus, the iPET result should not be used to guide changes in front-line or consolidative therapy for these patients.

Role of FDG PET-CT in the treatment management of Hodgkin lymphoma

Fluorodeoxyglucose (FDG) positons emission tomography (PET)-computed tomography (CT) is used in many ways at baseline and during the treatment of patients with Hodgkin lymphoma. Many properties of the technique are used in the different steps of patient's management. Initial staging with PET-CT is more accurate than conventional imaging and PET-CT also became the gold standard imaging at the end of treatment with a negative PET-CT mandatory for reaching a complete remission. Early assessment of response by PET-CT is one of the most powerful prognostic factors for progression-free survival of patients with localized and advanced stages and allows guiding treatment. Conversely, previous studies showed that there is no role of FDG PET-CT for the patient's follow-up.

Metabolic Tumor Volume Metrics in Lymphoma

Although visual assessment using the Deauville criteria is strongly recommended by guidelines for treatment response monitoring in all FDG-avid lymphoma histologies, the high rate of false-positives and concerns about interobserver variability have motivated the development of quantitative tools to facilitate objective measurement of tumor response in both routine and clinical trial settings. Imaging studies using functional quantitative measures play a significant role in profiling oncologic processes. These quantitative metrics allow for objective end points in multicenter clinical trials. However, the standardization of imaging procedures including image acquisition parameters, reconstruction and analytic measures, and validation of these methods are essential to enable an individualized treatment approach. A robust quality control program associated with the inclusion of proper scanner calibration, cross-calibration with dose calibrators and across other scanners is required for accurate quantitative measurements. In this section, we will review the technical and methodological considerations related to PET-derived quantitative metrics and the relevant published data to emphasize the potential value of these metrics in the prediction of patient prognosis in lymphoma.

Ultra-early response assessment in lymphoma treatment: [18F]FDG PET/MR captures changes in glucose metabolism and cell density within the first 72 hours of treatment

PURPOSE

To determine whether, in patients with Hodgkin lymphoma (HL) or non-Hodgkin lymphoma (NHL), [18F]FDG PET/MR can capture treatment effects within the first week after treatment initiation, and whether changes in glucose metabolism and cell density occur simultaneously.

METHODS

Patients with histologically proven HL or NHL were included in this prospective IRB-approved study. Patients underwent [18F]FDG PET/MR before, and then 48-72 h after (follow-up 1, FU-1) and 1 week after (FU-2) initiation of the first cycle of their respective standard chemotherapy (for HL) or immunochemotherapy (for NHL). Standardized [18F]FDG uptake values (SUVmax, SUVmean) and apparent diffusion coefficients (ADCmin, ADCmean) based on diffusion-weighted MRI, and metabolic and morphological tumour volumes (MTV, VOL) were assessed at each time-point. Multilevel analyses with an unstructured covariance matrix, and pair-wise post-hoc tests were used to test for significant changes in SUVs, ADCs, MTVs and VOLs between the three time-points.

RESULTS

A total of 58 patients (11 with HL and 47 with NHL) with 166 lesions were analysed. Lesion-based mean rates of change in SUVmax, SUVmean, ADCmin, ADCmean, MTV and VOL between baseline and FU-1 were -46.8%, -33.3%, +20.3%, +14%, -46% and -12.8%, respectively, and between baseline and FU-2 were -65.1%, -49%, +50.7%, +32.4%, -61.1% and -24.2%, respectively. These changes were statistically significant (P < 0.01) except for the change in VOL between baseline and FU-1 (P = 0.079).

CONCLUSION

In lymphoma patients, [18F]FDG PET/MR can capture treatment-induced changes in glucose metabolism and cell density as early as 48-72 h after treatment initiation.

Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL): A Multicenter, Randomized Phase III Trial

Purpose Interim positron emission tomography (PET) using the tracer, [¹⁸F]fluorodeoxyglucose, may predict outcomes in patients with aggressive non-Hodgkin lymphomas. We assessed whether PET can guide therapy in patients who are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Patients and Methods Newly diagnosed patients received two cycles of CHOP-plus rituximab (R-CHOP) in CD20-positive lymphomas-followed by a PET scan that was evaluated using the ΔSUV_max method. PET-positive patients were randomly assigned to receive six additional cycles of R-CHOP or six blocks of an intensive Burkitt's lymphoma protocol. PET-negative patients with CD20-positive lymphomas were randomly assigned or allocated to receive four additional cycles of R-CHOP or the same treatment with two additional doses rituximab. The primary end point was event-free survival time as assessed by log-rank test. Results Interim PET was positive in 108 (12.5%) and negative in 754 (87.5%) of 862 patients treated, with statistically significant differences in event-free survival and overall survival. Among PET-positive patients, 52 were randomly assigned to R-CHOP and 56 to the Burkitt protocol, with 2-year event-free survival rates of 42.0% (95% CI, 28.2% to 55.2%) and 31.6% (95% CI, 19.3% to 44.6%), respectively (hazard ratio, 1.501 [95% CI, 0.896 to 2.514]; P = .1229). The Burkitt protocol produced significantly more toxicity. Of 754 PET-negative patients, 255 underwent random assignment (129 to R-CHOP and 126 to R-CHOP with additional rituximab). Event-free survival rates were 76.4% (95% CI, 68.0% to 82.8%) and 73.5% (95% CI, 64.8% to 80.4%), respectively (hazard ratio, 1.048 [95% CI, 0.684 to 1.606]; P = .8305). Outcome prediction by PET was independent of the International Prognostic Index. Results in diffuse large B-cell lymphoma were similar to those in the total group. Conclusion Interim PET predicted survival in patients with aggressive lymphomas treated with R-CHOP. PET-based treatment intensification did not improve outcome.

Comparison Between Different PET and CT-Based Imaging Interpretation Criteria at Interim Imaging in Patients With Diffuse Large B-Cell Lymphoma

OBJECTIVE

To evaluate the predictive value of interim PET (iPET) in diffuse large B-cell lymphoma (DLBCL) using 5 different imaging interpretation criteria: Deauville 5-point scale criteria, International Harmonization Project (IHP) criteria, Response Evaluation Criteria In Solid Tumors (RECIST) 1.1, European Organization for Research and Treatment of Cancer, and PET Response Criteria in Solid Tumors (PERCIST) 1.0.

METHODS

We retrospectively reviewed records from 38 patients with DLBCL who underwent baseline and iPET at our institution. Imaging was interpreted according to the previously mentioned criteria. Results were correlated with end-of-treatment response, based on reports at the end of treatment radiological examinations, overall survival (OS), and progression-free survival (PFS) to assess and compare the predictive value of iPET according to each criterion. We also evaluated the concordance between different criteria.

RESULTS

The Deauville and PERCIST criteria were the most reliable for predicting end-of-treatment response, reporting an accuracy of 81.6%. They also correlated with OS and PFS (P = 0.0004 and P = 0.0001, and P = 0.0007 and P = 0.0002, for Deauville and PERCIST, respectively). Interim PET according to European Organization for Research and Treatment of Cancer also predicted the end-of-treatment response with an accuracy of 73.7% and had a significant correlation with OS (P = 0.007) and PFS (P = 0.007). In contrast, the IHP criteria and RECIST did not predict outcomes: the accuracy for end-of-treatment response was 34.2% and 36.8%, respectively, with no significant correlation with OS or PFS (P = 0.182 and P = 0.357, and P = 0.341 and P = 0.215, for OS and PFS, respectively).

CONCLUSIONS

The predictive value of iPET in DLBCL patients is most reliable using the Deauville and PERCIST criteria. Criteria that rely on anatomical characteristics, namely, RECIST and IHP criteria, are less accurate in predicting patient outcomes in DLBCL.

Interobserver Agreement of Interim and End-of-Treatment 18F-FDG PET/CT in Diffuse Large B-Cell Lymphoma: Impact on Clinical Practice and Trials

We aimed to assess the interobserver agreement of interim PET (I-PET) and end-of-treatment PET (EoT-PET) using the Deauville score (DS) in first-line diffuse large B-cell lymphoma (DLBCL) patients. Methods: I-PET and EoT-PET scans of DLBCL patients were performed in the HOVON84 study (2007-2012), an international multicenter randomized controlled trial. Patients received R-CHOP14 and were randomized to receive rituximab intensification in the first 4 cycles or not. I-PET was performed after 4 cycles (for observational purposes), and EoT-PET after 6 or 8 cycles. Two independent central reviewers retrospectively scored all scans according to the DS system, masked to clinical outcomes. Results were dichotomized as negative (DS of 1-3) or positive (DS of 4-5). Besides percentage overall agreement (OA), we calculated agreement for positive and negative scores, expressed as positive agreement (PA) and negative agreement (NA), respectively. Results: 465 I-PET and 457 EoT-PET scans were centrally reviewed; baseline ¹⁸F-FDG PET or PET/CT was available in 75%-77%, and CT in the remaining cases. Percentage OA for I-PET and EoT-PET were 87.7% and 91.7% (P = 0.049), with NA of 92.0% and 95.0% (P = 0.091), and PA of 73.7% and 76.3% (P = 0.656), respectively. Conclusion: Interobserver agreement using DS in DLBCL patients in I-PET and EoT-PET yields high OA and NA. The lower PA suggests that EoT-PET/CT treatment evaluation in daily practice and I-PET-adapted trials may benefit from dual reads and central review, respectively.

2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography in primary extranodal lymphomas: treatment response evaluation and prognosis

BACKGROUND

We evaluated the role of [18F]FDG PET/CT in tumor response assessment and prognosis of primary extranodal lymphoma (PEL) patients.

METHODS

We examined retrospectively, 56 PEL patients: 31 with aggressive diffuse large B cell lymphoma (DLBCL) and 25 with indolent lymphoma (20 mucosa-associated lymphoid tissue lymphoma and five follicular lymphoma). All patients had undergone [18F]FDG PET/CT at diagnosis (PET-I) and 50 of them also after therapy (PET-II). Moreover, 52 patients were subjected to a mean follow-up period of 76 months.

RESULTS

PET-I was positive in 50 (89%) patients (mean SUVmax 10.3±6.7). In the assessment of tumor response, according to Lugano classification, 45 patients showed complete metabolic response (CMR), four patients had partial metabolic response (PMR) and one had progressive metabolic disease (PMD). Based on 66% ΔSUVmax cut-off, among CMR patients, 41 showed a ΔSUVmax>66% whereas among non-responders, four patients showed a ΔSUVmax<66%. At follow-up, univariate analysis showed that age, performance status, prognostic index, ΔSUVmax and Lugano classification predicted progression-free survival (PFS) (P<0.05), while, performance status, prognostic index, ΔSUVmax and Lugano classification predicted overall survival (OS) (P<0.05). At multivariate analysis only Lugano classification was retained in the model for prediction of both PFS (P<0.05) and OS (P<0.05). By Kaplan-Meier analysis and log-rank testing both PFS and OS were significantly better in patients in CMR as compared to patients in PMR or PMD according to Lugano classification (P<0.01).

CONCLUSIONS

[18F]FDG PET/CT represents a useful tool in the detection of disease response and in the evaluation of outcome in PEL patients.

Defining the optimal method for measuring baseline metabolic tumour volume in diffuse large B cell lymphoma

PURPOSE

Metabolic tumour volume (MTV) is a promising prognostic indicator in diffuse large B cell lymphoma (DLBCL). Optimal thresholds to divide patients into 'low' versus 'high' MTV groups depend on clinical characteristics and the measurement method. The aim of this study was to compare in consecutive unselected patients with DLBCL, different software algorithms and published methods of MTV measurement using FDG PET.

METHOD

Pretreatment MTV was measured on 147 patients treated at Guy's and St Thomas' Hospital. We compared 3 methods: SUV ≥2.5, SUV ≥41% of maximum SUV and SUV ≥ mean liver uptake (PERCIST) and compared 2 software programs for measuring SUV ≥2.5; in-house 'PETTRA' software and Hermes commercial software.

RESULTS

There was strong correlation between MTV using the 4 methods, although derived thresholds were very different for the 41% method. Optimal cut-offs for predicting PFS ranged from 166-400cm³. All methods predicted survival with similar accuracy. 5y-PFS was 83-87% vs. 42-44% and 5y-OS was 85-89% vs. 55-58% for the low- and high-MTV groups, respectively. Interobserver variation in 50 patients showed excellent agreement, though variation was lowest using the SUV ≥ 2.5 method. The 41% method was the most complex and took the longest time.

CONCLUSION

All methods predicted PFS and OS with similar accuracy, but the derived cut-off separating good from poor prognosis varied markedly depending on the method. The choice of the optimal method should rely primarily on prognostic value, but for clinical use needs to take account of ease of use and reproducibility. In this study, all methods predicted prognosis, but SUV ≥ 2.5 had the best inter-observer agreement and was easiest to apply.

Prognostic value of pre- and post-transplantation 18F-fluorodeoxyglucose positron emission tomography results in non-Hodgkin lymphoma patients receiving autologous stem cell transplantation

Objective

High-dose chemotherapy (HDC) followed by autologous stem cell transplantation (ASCT) is the standard of care in the upfront or relapsed/refractory setting in some patients with non-Hodgkin lymphoma (NHL). However, a proportion of patients do not respond to ASCT. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been widely used for staging, response evaluation, and prognosis prediction. Here, we investigated the prognostic role of PET/CT in NHL patients before and after ASCT.

Methods

A retrospective study was conducted at Peking University Cancer Hospital. All NHL patients who underwent ASCT between March 2010 and July 2016 were identified. Patients who had PET/CT scan before and after ASCT were included. Deauville criteria (5-point scale) were used to interpret PET scans. Univariate and multivariate survival analyses were performed using Cox regression. The predictive value of PET scanning was estimated by comparing the area under the receiver operating characteristic (ROC) curve.

Results

In total, 79 patients were enrolled in this study. In univariate analysis, pre- and post-ASCT PET result was identified as prognostic factors for 3-year progression-free survival (PFS) and overall survival (OS). Patients with negative pre-ASCT PET result demonstrated significantly better PFS (84.2% vs. 54.2%) and OS (89.2% vs. 63.6%) than patients with positive pre-ASCT PET result. PFS (91.6% vs. 25.3%) and OS (96.5% vs. 36.8%) were also significantly different between patients with negative and positive post-ASCT PET result. Multivariate analysis also showed a significant association between survival and post-ASCT PET result. ROC analysis revealed that the predictive value of post-ASCT PET result was superior to that of pre-ASCT PET result alone. Combined pre- and post-ASCT PET result is better for predicting outcomes in patients with NHL receiving transplantation. Deauville criteria score >3 was identified as the best cutoff value for post-ASCT PET.

Conclusions

Post-ASCT PET result was more important than pre-ASCT PET result in predicting outcomes for NHL patients who underwent ASCT. The prognostic significance can be improved when combining pre-ASCT PET result with post-ASCT PET result. Deauville criteria can be used for interpreting PET scans in this scenario.