FDG-PET in Follicular Lymphoma Management

Prognostic value of the combination of volume, massiveness and fragmentation parameters measured on baseline FDG pet in high-burden follicular lymphoma

The prognostic value of radiomic quantitative features measured on pre-treatment 18F-FDG PET/CT was investigated in patients with follicular lymphoma (FL). We conducted a retrospective study of 126 FL patients (grade 1-3a) diagnosed between 2006 and 2020. A dozen of PET/CT-derived features were extracted via a software (Oncometer3D) from baseline 18F-FDG PET/CT images. The receiver operating characteristic (ROC) curve, Kaplan-Meier method and Cox analysis were used to assess the prognostic factors for progression of disease within 24 months (POD24) and progression-free survival at 24 months. Four different clusters were identified among the twelve PET parameters analyzed: activity, tumor burden, fragmentation-massiveness and dispersion. On ROC analyses, TMTV, the total metabolic tumor volume, had the highest AUC (0.734) followed by medPCD, the median distance between the centroid of the tumors and their periphery (AUC: 0.733). Patients with high TMTV (HR = 4.341; p < 0.001), high Tumor Volume Surface Ratio (TVSR) (HR = 3.204; p < 0.003) and high medPCD (HR = 4.507; p < 0.001) had significantly worse prognosis in both Kaplan-Meier and Cox univariate analyses. Furthermore, a synergistic effect was observed in Kaplan-Meier and Cox analyses combining these three PET/CT-derived parameters (HR = 12.562; p < 0.001). Having two or three high parameters among TMTV, TVSR and medPCD was able to predict POD24 status with a specificity of 68% and a sensitivity of 75%. TMTV, TVSR and baseline medPCD are strong prognostic factors in FL and their combination better predicts disease prognosis.

Accuracy and prognostic impact of FDG PET / CT and biopsy in bone marrow assessment of follicular lymphoma at diagnosis: A Nation‐Wide cohort study

BACKGOUND

In the workup of follicular lymphoma (FL), bone marrow biopsy (BMB) assessment is a key component of FLIPI and FLIPI2, the most widely used outcome scores. During the previous decade, several studies explored the role of FDG-PET/CT for detecting nodal and extranodal disease, with only one large study comparing both techniques.

METHODS

The aim of our study was to evaluate the diagnostic accuracy and the prognostic impact of both procedures in a retrospective cohort of 299 FL patients with both tests performed at diagnosis. In order to avoid a collinearity bias, FLIPI2 was deconstructed in its founding parameters, and the bone marrow involvement (BMI) parameter separately included as: a positive BMB, a positive PET/CT, the combined "PET/CT and BMB positive" or "PET/CT or BMB positive". These variables were also confronted independently with the POD24 in 233 patients treated with intensive regimens.

RESULTS

In the total cohort, bone marrow was involved in 124 and 60 patients by BMB and PET/CT, respectively. In terms of overall survival, age > 60 y.o. and the combined "PET/CT or BMB positive" achieved statistical independence as a prognostic factor. In patients treated with an intensive regimen, only the combined "PET/CT or BMB positive" added prognostic value for a shorter overall survival, when confronted with the POD24.

CONCLUSION

Our results show that in FL both BMB and PET/CT should be considered at diagnosis, as their combined assessment provides independent prognostic value in the context of the most widely use clinical scores.

Prognostic usefulness of clinical features and pretreatment 18F-FDG PET/CT metabolic parameters in patients with angiosarcoma

BACKGROUND

To investigate the prognostic value of clinical features and metabolic parameters in pretreatment 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/X-ray computed tomography (PET/CT) scans of patients with angiosarcoma, a rare neoplasm that has not been well characterized.

METHODS

In this retrospective study, 19 patients with a histopathologically confirmed diagnosis of angiosarcoma who had undergone pretreatment 18F-FDG PET/CT scans were enrolled. We recorded the age at presentation, sex, underlying diseases, sites of primary tumors, Karnofsky Performance Status (KPS) score, Eastern Cooperative Oncology Group (ECOG) score, time from onset to diagnosis, laboratory examinations, sites and sizes of primary tumors, treatment modalities, histologic features and American Joint Committee on Cancer (AJCC) stage, maximum standardized uptake value (SUVmax), average SUV (SUVavg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary tumors and the whole body. Univariate and multivariate survival analyses for overall survival were performed according to the metabolic parameters and other clinical variables.

RESULTS

Patients ranged in age from 27 to 79 years (median: 59 years) with different angiosarcoma types covering all tumor grades and subtypes. Seven (7/19) patients had anemia of varying degrees of severity. Lymph node metastases (n=10) and/or distant metastases (n=11) of angiosarcoma were common. Bone or bone marrow (10/19) and lung (8/19) were the most common distant metastatic organs. Patients with bone metastases, low hemoglobin levels and high ferritin levels had significantly poorer overall survival than those with non-bone metastases, normal hemoglobin levels and normal ferritin levels by the log-rank test, with P values of 0.027, 0.030 and 0.015, respectively. Patients with multiple organ metastases had significantly poorer overall survival than those with single organ metastasis (log-rank P=0.008). In multivariate survival analysis, only whole-body metabolic tumor volume using SUVmax cut-off value of 2.5 (wMTV2.5) was a significant independent prognostic factor. For wMTV2.5, 870.3 cm3 was the best cut-off point to discriminate between a good and poor prognosis (log-rank P=0.01).

CONCLUSIONS

The systemic 18F-FDG PET/CT with high sensitivity and specificity has significant advantages in the evaluation of angiosarcoma, particularly in detecting occult metastases. Bone metastases on 18F-FDG PET/CT, low hemoglobin levels and high ferritin levels were all associated with a poorer prognosis. MTV2.5 of the whole body is a significant independent metabolic prognostic factor for overall survival in patients with angiosarcoma.

Role of 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography Imaging in the Prediction of Prognosis in Patients With Indolent Lymphoma: Prospective Study

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.

Limited benefit of additional contrast-enhanced CT to end-of-treatment PET/CT evaluation in patients with follicular lymphoma

Despite follicular lymphoma (FL) is frequently characterized by a moderate increase of glucose metabolism, PET/CT examinations provides valuable information for staging and response assessment of the disease. The aim of the study was to assess and compare the diagnostic performance of PET/ldCT and PET/ceCT, respectively, in evaluating FL patients at the end of treatment. Fifty FL consecutive patients who underwent end-of-therapy PET/CT with both ldCT and ceCT were analyzed. Two blinded observers independently assessed PET/ldCT and PET/ceCT applying the Deauville score (DS) and Lugano classification criteria. PET imaging obtained after the end-of-treatment (EoT) was classified as showing PET and ce-CT matched response (concordant imaging group, CIG) or PET and ce-CT unmatched response (discordant imaging group, DIG). Relapse rate and Event-Free Survival (EFS) were compared between CIG and DIG patients. Overall, no differences in metabolic response classification were observed between PET/ldCT and PET/ceCT. In 13 (26%) patients PET/ceCT identified additional FDG-negative nodal lesions in mesenteric, retroperitoneal and iliac regions. However, in all cases, final DS remained unchanged and the additional results did not modify the following therapeutic decision. Among patients, who obtained complete metabolic response a comparable rate of relapse was registered in DIG 3/13 (23%) and CIG subgroups 5/20 (25%) [p = 0.899]. In all 3 DIG cohort patients who relapsed the recurrent disease involved also, but not exclusively, PET negative lymph nodes detected by ceCT. In overall population metabolic response defined by PET/ldCT predicted EFS [76% (group of patients with metabolic response) vs 35% (group of patients with residual disease), p = 0.0013] significantly better than ceCT-Based response assessment [75% (group of patients with complete response) vs 53% (group of patients with residual disease), p = 0.06]. Our study demonstrates a negligible diagnostic and predictive value of ceCT performed in addition to standard ¹⁸FDG PET/ldCT for EoT response evaluation in FLs. PET/ldCT should be performed as first-line imaging procedure, also in patients with prevalent abdominal and pelvic involvement, limiting the acquisition of ceCT in selected cases. This tailored approach would contribute to avoid useless radiation exposure and preserve renal function of patients.

Application of Quantitative Indexes of FDG PET to Treatment Response Evaluation in Indolent Lymphoma

Purpose

Although ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a standard imaging modality for response evaluation in FDG-avid lymphoma, there is a controversy using FDG PET in indolent lymphoma. The purpose of this study was to investigate the effectiveness of quantitative indexes on FDG PET in response evaluation of the indolent lymphoma.

Methods

Fifty-seven indolent lymphoma patients who completed chemotherapy were retrospectively enrolled. FDG PET/computed tomography (CT) scans were performed at baseline, interim, and end of treatment (EOT). Response was determined by Lugano classification, and progression-free survival (PFS) by follow-up data. Maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured in the single hottest lesion (target A) or five hottest lesions (target B). Their efficacies regarding response evaluation and PFS prediction were evaluated.

Results

On EOT PET, SUV_max, and MTV of both targets were well associated with visual analysis. Changes between initial and EOT PET were not significantly different between CR and non-CR groups. On interim PET, SUV_max, and %ΔSUV_max in both targets were significantly different between CR and non-CR groups. For prediction of PFS, most tested indexes were significant on EOT and interim PET, with SUV_max being the most significant prognostic factor.

Conclusion

Quantitative indexes of FDG PET are well associated with Lugano classification in indolent lymphoma. SUV_max measured in the single hottest lesion can be effective in response evaluation and prognosis prediction on interim and EOT PET.

High-grade Transformation of Low-grade B-cell Lymphoma: Pathology and Molecular Pathogenesis

Patients with low-grade (clinically indolent) lymphomas are at risk to undergo transformation to high-grade (clinically aggressive) lymphoma, although transformation only occurs in a subset of patients. When transformation occurs it is a critical event that determines the course of disease and is associated with unfavorable patient outcomes. Accurate detection of transformation, predictive biomarkers, and identification of specific molecular pathways implicated in the pathobiology of transformation will facilitate personalized therapeutic approaches and underpin advances in clinical outcomes. In this article, we present an update of the clinical and pathologic diagnostic criteria for low-grade B-cell lymphoma transformation and discuss the molecular alterations involved in the pathogenesis of this biological phenomenon.

Prognostic Value of FDG-PET, Based on the Revised Response Criteria, in Patients with Malignant Lymphoma: A Comparison with CT/MRI Evaluations, Based on the International Working Group/Cotswolds Meeting Criteria

OBJECTIVES

Post-treatment evaluations by CT/MRI (based on the International Working Group/Cotswolds meeting guidelines) and PET (based on Revised Response Criteria), were examined in terms of progression-free survival (PFS) in patients with malignant lymphoma (ML).

METHODS

79 patients, undergoing CT/MRI for the examination of suspected lesions and whole-body PET/CT before and after therapy, were included in the study during April 2007-January 2013. The relationship between post-treatment evaluations (CT/MRI and PET) and PFS during the follow-up period was examined, using Kaplan-Meier survival analysis. The patients were grouped according to the histological type into Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and other histological types. The association between post-treatment evaluations (PET or PET combined with CT/MRI) and PFS was examined separately. Moreover, the relationship between disease recurrence and serum soluble interleukin-2 receptor, lactic dehydrogenase, and C-reactive protein levels was evaluated before and after the treatment.

RESULTS

Patients with incomplete remission on both CT/MRI and PET had a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET and those exhibiting incomplete remission on CT/MRI and complete remission on PET (P<0.001). Post-treatment PET evaluations were strongly correlated with patient outcomes in cases with HL or DLBCL (P<0.01) and other histological types (P<0.001). In patients with HL or DLBCL, incomplete remission on both CT/MRI and PET was associated with a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET (P<0.05) and those showing incomplete remission on CT/MRI and complete remission on PET (P<0.01). In patients with other histological types, incomplete remission on both CT/MRI and PET was associated with a significantly shorter PFS, compared to cases with complete remission on both CT/MRI and PET (P<0.001). None of the serum parameters differed significantly between recurrent and non-recurrent cases.

CONCLUSION

Post-treatment PET evaluations were well correlated with the outcomes of patients with ML, exhibiting FDG uptake. Among patients with HL or DLBCL, a post-treatment complete remission on PET was predictive of a relatively long PFS. For predicting the prognosis of patients with other histological types, a combination of CT/MRI and PET, rather than PET alone, is recommended.

Comparative effectiveness research in follicular lymphoma: current and future perspectives and challenges

Follicular lymphoma (FL) is the most common indolent non-Hodgkin's lymphoma in northern America. FL is an incurable disease with relapsing-remitting courses requiring serial intermittent treatments. Duration of remission will often become progressively shorter and most patients will die from refractory disease or transformation to aggressive lymphoma. Given the incurable nature of FL, current goals of treatment are focused on improving symptoms and survival by a variety of available treatment options, while considering potential adverse events. Although randomized controlled trials are universally perceived as the gold standard of clinical research, randomized controlled trials are not always practical and have several limitations. Therapeutic and diagnostic options of FLs are expanding faster than randomized controlled trials can test them, so employing comparative effectiveness research on other research designs are needed to efficiently improve global FL care. Implementing comparative effectiveness research with judicious use of appropriate research designs will hopefully fill current knowledge gaps and provide insights for FL managements.

Incorporating prognostic imaging biomarkers into clinical practice

A prognostic imaging biomarker can be defined as an imaging characteristic that is objectively measurable and provides information on the likely outcome of the cancer disease in an untreated individual and should be distinguished from predictive imaging biomarkers and imaging markers of response. A range of tumour characteristics of potential prognostic value can be measured using a variety imaging modalities. However, none has currently been adopted into routine clinical practice. This article considers key examples of emerging prognostic imaging biomarkers and proposes an evaluation framework that aims to demonstrate clinical efficacy and so support their introduction into the clinical arena. With appropriate validation within an established evaluation framework, prognostic imaging biomarkers have the potential to contribute to individualized cancer care, in some cases reducing the financial burden of expensive cancer treatments by facilitating their more rational use.