Treatment Response In Lymphoma Research Articles

CO201 Feasibility of Using Positron Emission Tomography–Computed Tomography (PET-CT) Scans From Real-World Medical Record Data to Support Lymphoma Treatment Response Assessment

CO201 Feasibility of Using Positron Emission Tomography–Computed Tomography (PET-CT) Scans From Real-World Medical Record Data to Support Lymphoma Treatment Response Assessment

Role of interim positron emission tomography/computed tomography in assessment of lymphoma treatment response

BackgroundLymphoma is the most common primary hematological malignancy. FDG PET/CT has recently become the standard imaging modality for clinical management owing to its ability to provide precise, non-invasive anatomical and functional data. The purpose of this study was to highlight the role of 18F FDG-PET/CT in the management of lymphoma by monitoring treatment response, providing a guide for response-adapted therapy, and predicting the final therapeutic outcome.MethodsThis was a prospective monocentric cohort observational study in which thirty-three patients with histopathologically proved lymphoma of different types performed FDG-PET/CT scanning several times throughout the 24-month duration of the study. Early-stage interim SUVmax of the most active lesion (both nodal and/or extra-nodal) was measured and statistically analyzed together with data of the international prognostic index parameters and score.ResultsAmong the included 33 patients of lymphoma, international prognostic index parameters and score together with the early-stage interim SUVmax of the predominant nodal and extra-nodal sites showed statistical significance in predicting the initial as well as the final treatment response after 24 months. Using ROC analysis, we could obtain cutoff values of SUVmax of the predominant nodal lesion of 2.75 (AUC 72%, 95% CI 0.42–1.0) and SUVmax of the predominant extra-nodal lesion of 3 (AUC 70.8% and 95% CI 0.23–1.0); therefore, SUVmax of higher than these values was related to stable or progressive disease, and lower levels than these values were related to complete or partial metabolic response based on Deauville 5-point scale and Lugano response criteria.ConclusionsEarly-stage interim PET-CT SUVmax of the predominant nodal and extra-nodal lesion could be a reliable parameter in predicting initial and final therapeutic outcome in lymphoma patients.

The effect of 18F-FDG PET/CT findings on prognosis in patients with diffuse large B cell lymphoma

Aims: 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT), plays an important role in both staging at the time of diagnosis and follow-up of treatment response in lymphoma. Our aim was to investigate the effect of different quantitative metabolic parameters, which are not used in routine practice, on treatment response and overall survival (OS) in patients with diffuse large B-cell lymphoma.
 Methods: A total of 26 patients were included in our retrospective cohort study. Deauville 5-point scale (5-PS), and cut-off values for changes in maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), metabolic tumor volume (MTV)(2.5-%41- PERCIST -aort) and total lesion glycolysis index (TLG) (2.5-%41- PERCIST-aort) effect of metabolic parameters on treatment response and OS was investigated.
 Results: Metabolic parameters did not predict treatment response, while TLGPERCIST (p=0.034), TLGAORT (p=0.040), MTV41 (p=0.040) and TLG41 (p=0.034) parameters were statistically significant for OS. Median OS (months) was statistically significant in TLGPERCIST groups (p=0.047). While the median OS (months) in the TLGPERCIST

Abbreviated whole‐body MRI for follow‐up in pediatric lymphoma: results of a multicenter prospective study

Introduction: The evaluation of treatment response in pediatric lymphoma is critical for making informed treatment decisions and improving patient outcomes. Positron emission tomography/computed tomography (PET/CT) and traditional whole-body magnetic resonance imaging (MRI) are the most commonly used imaging modalities for assessing treatment response in lymphoma. However, PET/CT exposes patients to ionizing radiation, and its high cost and limited availability may limit its use for routine follow-up. Traditional whole-body MRI is a noninvasive alternative, but it has some limitations, including prolonged acquisition time and the need for sedation, which can be burdensome for pediatric patients. Abbreviated whole-body MRI (AWBMRI) has emerged as a promising imaging modality for monitoring treatment response in pediatric lymphoma. AWBMRI requires less time and is typically performed without sedation, making it a potentially more feasible and patient-friendly alternative to traditional MRI for routine follow-up. Methods: A multicenter prospective study was conducted, enrolling 103 pediatric patients aged 0 to 18 years with pathologically confirmed lymphoma. All patients underwent both PET/CT and abbreviated whole-body MRI at baseline and during follow-up. Image quality of abbreviated whole-body MRI was evaluated using a 5-point Likert scale, and interobserver agreement was assessed. Sensitivity, specificity, and accuracy of abbreviated whole-body MRI for detecting residual or recurrent disease were calculated, with PET/CT used as the reference standard. Results: Image quality of abbreviated whole-body MRI was rated as good or excellent in 97% of cases, with high interobserver agreement. Abbreviated whole-body MRI demonstrated a sensitivity of 90%, specificity of 96%, and accuracy of 94% for detecting residual or recurrent disease, with excellent agreement between abbreviated whole-body MRI and PET/CT findings. Keyword: Other No conflicts of interests pertinent to the abstract.

Prompt Assessment of Tumor Load and Treatment Response in Patients with Lymphoma By a Blood-Based Multi-Omics Approach

Introduction Lymphoma is a class of highly heterogeneous hematological malignancy derived from malignant clonal proliferation of lymphocytes. Periodic imaging examinations are the current standard for clinical assessment of lymphoma treatment response. Liquid biopsy is an emerging, non-invasive method for quantitative assessment of cancer treatment response. In this prospective study, we applied a noninvasive multi-omics assay named SeekInClarity to assess lymphoma treatment response and predict patient outcomes. Methods 149 patients meeting the WHO diagnosis criteria of lymphoid neoplasm were prospectively recruited from two clinical sites. The study is in progress, and 114 patients were included in the current interim analysis. 8.8% of patients who were lost to follow-up or quickly died were excluded. SeekInClarity assay integrates the analysis of genomic feature and common plasma tumor protein markers (PTMs, including AFP, CEA, CA153, CA125, CA199, CYFRA21-1 and CA724). Genomic features including copy number aberration (CNA) and the fragment size (FS) that are pan-cancer hallmarks were analyzed by shallow whole genome sequencing. Patients received SeekInClarity test before and after 1, 2, 4 and 6 cycles of treatment to generate the molecular tumor burden score (MTB). MTB positive/negative suggests that molecular signal of tumor is detectable/undetectable. Results The value of each dimension (protein marker, CNA and FS) in the prior-treatment (baseline) lymphoma samples were significantly higher than that in healthy control samples (Mann-Whitney test: P<0.001). 72.8% base line samples were MTB positive. After 2 cycles of treatment, the samples from patients who experienced disease progression showed higher MTB positivity rate than that from those without disease progression (85.7% vs. 26.7). MTB- patients showed a significantly longer progression free survival (PFS) time than MTB+ patients [HR: 12.6, 95% CI:4.1-38.6, P<0.0001] regardless of tumor stage and lymphoma subtype. Patients with reduced sample MTB values compared to baseline sample MTB values after two cycles of treatment had significantly better disease-free survival than patients with increased sample MTB values after treatment [HR: 5.0, 95% CI:0.48-52.5; P<0.0001]. We further divided the patients into two groups according to the degree of reduction in MTB values in the pre- and post-treatment samples (>50% & <50%), and we found that patients with higher MTB decrease (>50%) showed a better PFS than those with lower MTB decrease (<50%, P < 0.001). Conclusions This prospective study demonstrated that SeekInClarity, a non-invasive, multidimensional blood-based assay, can promptly evaluate the treatment response of lymphoma patients, and the MTB status showed an excellent correlation with clinical outcome. The dynamic change of MTB exhibited a good prognostic power of lymphoma. It challenged the status quo of employing imaging as a sole standard for evaluating early treatment response.

64 Cu-DOTA-Rituximab PET/CT of B-Cell Non-Hodgkin Lymphoma for Imaging the CD20 Expression.

64 Cu-DOTA-rituximab PET/CT was performed on a 62-year-old and a 71-year-old men diagnosed with B-cell non-Hodgkin lymphoma. Compared with 18 F-FDG PET/CT, lesions could be detected more sensitively, and it was confirmed that there was no discernible 64 Cu-DOTA-rituximab uptake in the tumor other than lymphoma. 64 Cu-DOTA-rituximab PET/CT could be a powerful tool for the diagnosis and monitoring treatment response of lymphoma because of imaging the CD20 expression.

P1249: INHIBITION OF THE PENTOSE-PHOSPHATE-PATHWAY (PPP) MEDIATES MACROPHAGE REPROGRAMMING FROM SUPPORTIVE BYSTANDER FUNCTION TOWARDS ANTIBODY-DEPENDENT LYMPHOMA CELL CLEARANCE AND LYMPHOMA SUPPRESSION

Background: Treatment response in lymphoma depends on the interaction and functional status of macrophages as important effector cells for tumor cell clearance by antibody-dependent cellular phagocytosis (ADCP). In the tumor microenvironment (TME) there is a limited supply of nutrients which implicates metabolic reprograming of immune cells such as changed phagocytic capacity of macrophages. Aims: We aimed to identify metabolic pathways regulating macrophages in the TME to improve macrophage effector cell function in lymphoma therapy. Methods: We addressed macrophage lymphoma cell co-cultures using macrophage cell lines, primary murine macrophages and human monocyte-derived macrophages. For pathway inhibition specific compounds as well as shRNA-mediated knockdown were used for functional read-out of ADCP and viability in lymphoma co-culture. Macrophage reprogramming was assessed by microscopy, FACS-immunophenotyping, ELISA, (phospho)-proteomic and metabolomic assessment. C57BL/6 mice and the humanized aggressive lymphoma model hMB were used for in vivo treatment with the pentose phosphate pathway (PPP) inhibitor S3 and analysis of macrophage programming and overall survival. Results: Inhibition of AMP kinase, glycolysis or mitochondrial ATP-production did not increase the phagocytosis rate in ADCP co-cultures. Inhibiting the PPP induced an increased lymphoma cell phagocytosis by macrophages. Under PPP-inhibition, the oxygen consumption and the glycolysis of macrophages was increased and the cells developed a more activated morphology with formation of filopodia, which are needed for phagocytosis initiation. Moreover, a down-regulation of immune-inhibitory surface proteins PD-L1 and SIRP1α was seen and cytokine secretion was shifted from anti-inflammatory IL10 to pro-inflammatory IL6 secretion. PPP-inhibition of macrophages significantly reduced CLL-cell support in vitro abrogating the “nurse-like” effect of macrophages. The increased lymphoma cell clearance and phenotypic alterations of macrophages were also observed in PPP-enzyme knockdown of transketolase (TKT) and 6-phosphogluconatedehydrogenase (6PGD) in macrophages and by inhibiting the PPP in primary murine and human macrophages. In a multiomics assessment of PPP-inhibition on proteome, phosphoproteome and metabolome level, we found protein expression alterations regulating metabolism and immunity. A connection between PPP inhibition and changed immune profile by modulation of the Stat1-Irg1-itaconate axis was identified and validated. In a humanized lymphoma mouse model the addition of PPP-inhibitor S3 led to significant prolonged survival of lymphoma bearing mice and an increased maturation and pro-inflammatory polarization of macrophages. Summary/Conclusion: An increased maturation, activation and repolarization of macrophages towards a pro-inflammatory and phagocytic active phenotype was observed by inhibiting the pentose-phosphate-pathway (PPP). This led to a significant survival benefit in in vivo lymphoma mouse model. We were able to point out the underlying Stat1-Irg1-itaconate signalling axis, connecting metabolic regulation and immune-phenotype of macrophages. We hypothesize the PPP as a key regulator of macrophage function determining the support of malignant B cell growth versus the capacity of lymphoma cell clearance and thereby therapy outcome. By that, we have identified the PPP as a targetable modulator of macrophage polarization to improve efficacy of B cell lymphoma and CLL therapy.

Assessment of Early Therapy Response of Non-Hodgkin's and Hodgkin's Lymphoma Using B-Mode Ultrasound and Dynamic Contrast-Enhanced Ultrasound.

Here we asked, whether contrast enhanced ultrasound (CEUS) enables to judge early treatment response in malignant lymphoma as a potential guidance for further treatment. From May 2017 to May 2018, 21 patients with histologically confirmed diagnosis of lymphoma were examined by B-mode ultrasound (B-US) and CEUS at fixed early time points after commencing therapy (days [d] 0, 15 and 30 after therapy start) and contrast enhancement patterns in target lymphoma lesions were quantified using Bracco-VUE Box® (DCE-US). To estimate the potential value of CEUS-enhancement patterns for early response prediction, patients were grouped according to their best achieved actual response into complete remission (CR) patients, partial remission (PR) patients or progressive disease (PD) patients. Between d0, d15 and d30, CR-patients showed a median lymphoma shrinking by 34% in B-US. PD-patients experienced a median lymphoma size reduction by 44% on day 15, but lymphoma mass again increased by 20% between d15 and d30. In contrast, the median CEUS enhancement intensity, as assessed by the area under the curve (AUC) was increasing at d15 in CR and PD patients (CR to 152%, PD: to 126%), but decreased at d30 to 14% in CR patients and 22% in PD patients. While early response assessment using B-US might be useful to predict treatment response in lymphoma, CEUS and DCE-US-although often feasible-do not provide additional value in this regard.

PET/CT in the Evaluation of the Treatment Response in Lymphomas

PET/CT in the Evaluation of the Treatment Response in Lymphomas

Les lymphomes non-Hodgkiniens osseux de l’adulte

Two forms of bone lymphomas can be distinguished: the primary bone lymphoma (PBL) and the secondary bone lymphoma (SBL). PBL is a rare disease with a good prognosis. Clinical manifestations and imaging findings are usually non-specific. Patient can present with pain, swelling of affected bone or pathologic fracture. Positron emission tomography-CT scan is a sensitive imaging modality and very useful for staging, restaging, surveillance of recurrence, and monitoring of treatment response of lymphoma. The diagnosis of PBL is often difficult and made after biopsy examination. Most patients have diffuse large B-cell lymphoma. Patients have been treated with radiotherapy, chemotherapy or combination of both. Localized disease, low IPI (International Prognostic Index) and complete remission after initial treatment were associated with a better outcome. Management of late sequelae deserves particular attention. SBL is more common than PBL; this is a disseminated lymphoma with concomitant involvement of the skeleton. We review the clinical, imaging and pathologic features of bone lymphomas; and discuss therapeutic modalities as well as prognosis of these lymphomas in the era of immunochemotherapy.

Lugano classification: response evaluation criteria for positron emission tomography/computed tomography in lymphoma follow-up

BackgroundThe purpose of this study is to assess the role of 18 fluorodeoxyglucose positron emission tomography/computed tomography (18FDG PET-CT) in the follow-up of patients with lymphoma after finishing therapy.ResultsThis study included 42 lymphomas (25 non-Hodgkin’s lymphoma and 17 Hodgkin’s lymphoma); patients ranging in age from 18 to 70 years were examined by 18FDG PET-CT after therapy and analyzed retrospectively. Confirmatory biopsy was mandatory in cases of suspected disease recurrence and follow-up in cases of complete metabolic response. Positron emission tomography/computed tomography in assessment of lymphoma treatment response reveals significant statistical significance (P < 0.05). It shows 100% sensitivity, 92.8% specificity, and 95.2% accuracy in the prediction of response.ConclusionPositron emission tomography/computed tomography plays an important role in detection of response to treatment of lymphoma after finishing therapy.

Functional imaging using radiomic features in assessment of lymphoma.

Lymphomas are typically large, well-defined, and relatively homogeneous tumors, and therefore represent ideal targets for the use of radiomics. Of the available functional imaging tests, [18F]FDG-PET for body lymphoma and diffusion-weighted MRI (DWI) for central nervous system (CNS) lymphoma are of particular interest. The current literature suggests that two main applications for radiomics in lymphoma show promise: differentiation of lymphomas from other tumors, and lymphoma treatment response and outcome prognostication. In particular, encouraging results reported in the limited number of presently available studies that utilize functional imaging suggest that (1) MRI-based radiomics enables differentiation of CNS lymphoma from glioblastoma, and (2) baseline [18F]FDG-PET radiomics could be useful for survival prognostication, adding to or even replacing commonly used metrics such as standardized uptake values and metabolic tumor volume. However, due to differences in biological and clinical characteristics of different lymphoma subtypes and an increasing number of treatment options, more data are required to support these findings. Furthermore, a consensus on several critical steps in the radiomics workflow -most importantly, image reconstruction and post processing, lesion segmentation, and choice of classification algorithm- is desirable to ensure comparability of results between research institutions.

Comparison between RECIST and PERCIST criteria in therapeutic response assessment in cases of lymphoma

BackgroundAccurate radiologic assessment of treatment response in lymphomas is important for helping the clinicians to properly evaluate effectiveness of treatment and consequently guide therapeutic management of these patients. Imaging tools based on anatomic response are suboptimal in detecting functional changes in tumors resulting after early effective treatment. Recently, with the development of 18F-FDG PET/CT, both functional and anatomic information has been integrated for assessing treatment response in both solid tumors and hematologic malignancies. The aim of this study was to compare therapeutic response in lymphoma patients using both RECIST 1.1 and PERCIST 1.0 criteria.ResultsAmong the included 33 lymphoma patients, RECIST 1.1 and PERCIST 1.0 classifications of therapeutic response were concordant in 20 patients (60.6%) and discordant in 13 patients (39.4%), with a tendency of RECIST 1.1 to downgrade the tumor response in 12/13 patients (P value < 0.001).ConclusionThe recently applied PERCIST 1.0 is efficient and more accurate than RECIST 1.1 to assess treatment response in lymphoma patients, which is subsequently affecting further management of these patients.

Circulating Epstein-Barr virus DNA and cell-free DNA in pediatric lymphomas.

Quantification of serum Epstein-Barr virus (EBV) DNA and/or cell-free total DNA (cf-DNA) may become valuable sources for prognosis evaluation and monitoring treatment response in lymphomas. We aimed to investigate their roles as potential markers in pediatric Hodgkin (HL) and non- Hodgkin lymphomas (NHL). Between the years 2005-2008, 34 patients with HL and 45 with NHL were prospectively included. Serum samples were collected upon diagnosis, after 1-3 and 4-6 months and at the end of treatment, or at disease recurrence. RT-PCR determination of cf-DNA and EBV DNA were performed using amplification of BAMH1W region of EBV genome and of human β-globin gene. Results were analyzed for correlation with clinical and pathological characteristics. Median ages were 8.9 years for HL and 8.8 years for NHL cases. Twenty-three healthy children cured from various childhood cancers served as the control group. In the controls, median serum EBV DNA copy number was `0` and median serum cf-DNA level was 50 ng/ml. At initial diagnosis, serum EBV DNA copy numbers were elevated in 20/34 HL and 8/45 NHL cases (p < 0.001). Median serum EBV DNA copy numbers were 15987/mL (125-6032075) and 25162 (1475-1214550) for HL and NHL cases, respectively (p= 0.9). Median serum cf-DNA levels were 435 ng/ml (2.3-17306) in HL and 700 ng/ml (4.9-14009) in NHLs (p= 0.12). Serum EBV DNA copy numbers and cf-DNA levels decreased significantly after induction treatment and in the follow-up. In 10/13 NHL cases with a relapse, marked elevations were detected in serum cf-DNA levels at recurrences. No significant differences were detected between median cf-DNA levels according to disease stages, response status to treatment or presence of recurrent disease. Serum EBV DNA copy numbers and cf-DNA levels were elevated at initial diagnosis in both HLs and NHLs and decreased parallel to treatment response. In NHL cases, remarkable elevation of cf-DNA levels at recurrences indicated that cf-DNA levels might be useful in the follow-up of pediatric NHLs.

RECIL versus Lugano for Treatment Response Assessment in FDG-Avid Non-Hodgkin Lymphomas: A Head-to-Head Comparison in 54 Patients.

The response evaluation criteria in lymphoma (RECIL) classification for lymphoma treatment response assessment was introduced in 2017, but it has not yet been compared to the established Lugano classification. Also, the value of the provisional “minor response” (MiR) category of RECIL is unclear. In 54 patients with FDG-avid non-Hodgkin lymphomas (41 diffuse large B-cell lymphomas (DLBCL) and 13 follicular lymphomas), [18F]FDG-PET/CT-based response according to RECIL and Lugano was determined at interim and end-of-treatment (EOT) restaging. Rates of agreement and Cohen’s kappa (κ) coefficients were calculated. The relationship between RECIL and Lugano responses and 2-year complete remission (CR) status of DLBCL patients was determined. At interim restaging, MiR was observed in 14.8%, and at EOT, in 5.6% of patients. When MiR was recoded as partial remission, agreement between RECIL and Lugano was 83.3% at interim restaging (κ = 0.69), and 90.7% at EOT (κ = 0.79). 85.4%, of DLBCL patients with responding disease at interim restaging according to both RECIL and Lugano achieved 2-year CR status; whereas, at EOT, 82.9% of patients with responding disease according to Lugano, and 85.4% of patients with responding disease according to RECIL, achieved 2-year CR status. Thus, RECIL and Lugano classifications show comparable performance for treatment response assessment, and a similar association with 2-year CR status in FDG-avid lymphomas.

TAC y PET/TC con 18-FDG para evaluar la respuesta al tratamiento en linfoma de Hodgkin y no Hodgkin

The assessment of lymphoma response to treatment is based on imaging studies. To correlate the assessment of lymphoma treatment response by computed tomography (CT) and by positron emission tomography/computed tomography (PET/CT). Cross-sectional, observational study, where records of patients with lymphoma under surveillance by CT and PET/CT were reviewed. The study population consisted of 43 patients with a mean age of 32.7 ± 22.4 years; 26 (60.5 %) had a diagnosis of Hodgkin's lymphoma and 17 (9.5 %) had non-Hodgkin lymphoma. By CT, 34 (79.1 %) were diagnosed with disease and nine (20.9 %) without disease. The criteria used to assess the response was radiologist experience in 39 (90.7 %) and RECIST 1.1 criteria in four (9.3 %). The diagnosis by 18-FDG PET/CT was no response to treatment or partial response-recurrence in 32 (74.4 %) and response to treatment in 11 (25.6 %); with PERCIST criteria in 13 (30.2 %) and Deuaville criteria in 30 (69.8 %). When the diagnosis by CT versus 18-FDG PET/CT was compared, out of 11 patients with complete response on PET/CT, three had a similar CT diagnosis. Of the 34 patients with data consistent disease diagnosed by CT, 26 had similar results by 18-FDG PET/CT (p = 0.54). The value of lymphoma treatment response on CT does not agree with that obtained by 18-FDG PET/CT.

PROSPECTIVE STUDY OF 3T WHOLE BODY DIFFUSION WEIGHTED MAGNETIC RESONANCE (WB DWI MRI) COMPARED TO PET IN STAGING AND ASSESSMENT OF TREATMENT RESPONSE IN FDG AVID LYMPHOMAS

Introduction: PET is considered the gold standard for staging and evaluation of treatment response in FDG avid Lymphoma. 3T WB-DWI-MRI may represent an option for detection and better characterisation of tumoral lesions without use of FDG or iodated/paramagnetic contrast medium. We compared 3T WB-DWI-MRI with PET in the evaluation of Hodgkin lymphoma (HL) and Diffuse large cell lymphoma patients (DLBCL). Methods: From may 2016, 25 patients (14 cases of HL and 11 cases of DLBCL) were diagnosed at our institution. PET and 3T WB-DWI-MRI was perfomed at diagnosis and post treatment for a total of 118 nodal sites and 21 extranodal valued sites. DWI imaging was obtained with multi shot sequences (thickness 4 mm) multi-b (b-value: 0, 150, 1000) and ADC cut off value 1.2 for functional evaluation. Morphological images were obtained by using sequences fast spin-echo short time inversion recovery (STIR with thickness 4mm) and Turbo spin-echo (T2-TSE with thickness 4mm) and sequnces T1-FAST-Field-echo (T1-FFE) in and out - phase (thickness 4mm). MRI were compared with PET imaging performed at the same time and assessed blind by radiologist and Nuclear Medicine physician. Results: The 3T WB-DWI-MRI and PET results were concordant at the diagnosis after evaluation of 118 nodal site and 21 extra nodal site with Cohen's Kappa coefficient showed agreement to be excellent (K = 0.82 and 0.84 respectively). When performed after treatment the two methods were not concordant due to the greater sensitivity and specificity of the RMI (high positive and negative predictive value. In 5/25 cases of nodal site and in 2/16 cases of extra nodal site after chemotherapy MRI and PET results were discordant and PET failed complete remission finding (doubts residues after therapy not confirmed at subsequent follow-up). Conclusions: These data suggest that 3T WB-DWI-MRI can be considered a sensitive and specific method for assessing treatment response in Lymphoma without the use of ionising radiation or administration of F-18 Flurodeoxyglucose. In this population, MRI appears to obtain a better definition of the response after chemotherapy especially in mediastinal, hepatic, waldeyer ring and bone sites. Further studies are needed to evaluate the optimum ADC values in assessing treatment response in a more large number of patients. Keywords: diffuse large B-cell lymphoma (DLBCL); Hodgkin lymphoma (HL); positron emission tomography (PET).

Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography as a diagnostic tool in therapeutic evaluation of lymphoma after completion of therapy

PurposeThis study aimed at assessment of the role of (PET/CT) in lymphoma after completion of therapy to differentiate post-treatment fibrosis from residual viable tumor and being familiar with the limitations and interpretative pitfalls of PET/CT. Method and materialsThe present study was performed on 50 patients(27 males and 23 females).18F-FDG was injected IV one hour before performing the study. Contrast enhanced CT was performed followed by PET. ResultsAfter the end of therapy; PET/CT revealed (38%) of cases showed a partial regression, (28%) of cases showed a progressive disease, (22%) of cases with complete metabolic disease remission, (8%) of cases showed a stationary disease and the remaining (4%) of cases showed mixed response to therapy. CT only agreed with PET/CT in 76% of the cases. Some physiologic uptake often occurs after treatment in (4%) of patients. PET/CT has 100% sensitivity,68.75 % specificity, 87.17% PPV, 100% NPV and 90% accuracy in treatment response of lymphoma; compared to 94.1% sensitivity and 50% specificity, 80% PPV, 80% NPV and 80% accuracy for CECT. ConclusionPET/CT is a multimodality technique that can accurately monitor the treatment response of lymphoma. It can differentiate residual mass containing viable tumor from post treatment fibrosis.

Diagnostic accuracy of diffusion-weighted imaging- magnetic resonance imaging compared to positron emission tomography/computed tomography in evaluating and assessing pathological response to treatment in adult patients with lymphoma: A systematic review.

The use of Positron emission tomography/computerised tomography (PET/CT) is well established in the staging and assessment of treatment response of lymphoma. Recent studies have suggested that whole body diffusion-weighted imaging -magnetic resonance imaging (WB-DW-MRI) may be an alternative to PET/CT in both staging and assessment of treatment response. A systematic review was performed to assess the ability of DW-MRI in the assessment of treatment response in lymphoma. Pubmed, Medline, Web of Science and Embase databases were queried for studies examining whole body DW-MRI compared to PET/CT in adult patients using a protocol of search terms. We carried out an extensive assessment of titles, abstracts and full texts of relevant paper as well as quality assessment with the Quality Assessment of Diagnostic Accuracy (QUADAS-2) tool. Eight studies were found to meet the criteria and were included in our review and analysis. Overall, the quality of studies was found to be moderate, with good inter-rater agreement (K=0.74). Data analysis showed that lesion-based assessment in 5 studies with pooled results had a sensitivity and specificity of 94.7% and 99.3%. Assessment with Cohen's Kappa coefficient showed agreement to be excellent (K=0.88). Three studies were included for qualitative analysis, two of which showed good equivalence between PET/CT and DW-MRI. WB-DWI-MRI can be considered a sensitive and specific method for assessing treatment response in Lymphoma without the use of ionising radiation or administration of F-18 Flurodeoxyglucose. Further studies are needed to evaluate the optimum b-values in assessing treatment response.

Evaluation of Whole Body DiffusionWeighted Imaging in the Staging and Treatment Response of Lymphoma Compared With Fluoride-Oxyglucose (FDG) PET/CT as a Reference Standard

Evaluation of Whole Body DiffusionWeighted Imaging in the Staging and Treatment Response of Lymphoma Compared With Fluoride-Oxyglucose (FDG) PET/CT as a Reference Standard