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.
PET using
18
F-FDG for treatment monitoring in patients with lymphoma is one of the most well-developed clinical applications. PET/CT is nowadays used during treatment to assess chemosensitivity, ...with response-adapted therapy given according to ‘interim’ PET in clinical practice to adults and children with Hodgkin lymphoma. PET is also used to assess remission from disease and to predict prognosis in the pretransplant setting. Mature data have been reported for the common subtypes of aggressive B-cell lymphomas, with more recent data also supporting the use of PET for response assessment in T-cell lymphomas. The Deauville five-point scale incorporating the Deauville criteria (DC) is recommended for response assessment in international guidelines. FDG uptake is graded in relation to the reference regions of normal mediastinum and liver. The DC have been validated in most lymphoma subtypes. The DC permit the threshold for adequate or inadequate response to be adapted according to the clinical context or research question. It is important for PET readers to understand how the DC have been applied in response-adapted trials for correct interpretation and discussion with the multidisciplinary team. Quantitative methods to perform PET in standardized ways have also been developed which may further improve response assessment including a quantitative extension to the DC (qPET). This may have advantages in providing a continuous scale to refine the threshold for adequate/inadequate response in specific clinical situations or treatment optimization in trials. qPET is also less observer-dependent and limits the problem of optical misinterpretation due to the influence of background activity.
The purpose of this work was to modernize recommendations for evaluation, staging, and response assessment of patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). A workshop was held ...at the 11th International Conference on Malignant Lymphoma in Lugano, Switzerland, in June 2011, that included leading hematologists, oncologists, radiation oncologists, pathologists, radiologists, and nuclear medicine physicians, representing major international lymphoma clinical trials groups and cancer centers. Clinical and imaging subcommittees presented their conclusions at a subsequent workshop at the 12th International Conference on Malignant Lymphoma, leading to revised criteria for staging and of the International Working Group Guidelines of 2007 for response. As a result, fluorodeoxyglucose (FDG) positron emission tomography (PET)–computed tomography (CT) was formally incorporated into standard staging for FDG-avid lymphomas. A modification of the Ann Arbor descriptive terminology will be used for anatomic distribution of disease extent, but the suffixes A or B for symptoms will only be included for HL. A bone marrow biopsy is no longer indicated for the routine staging of HL and most diffuse large B-cell lymphomas. However, regardless of stage, general practice is to treat patients based on limited (stages I and II, nonbulky) or advanced (stage III or IV) disease, with stage II bulky disease considered as limited or advanced disease based on histology and a number of prognostic factors. PET-CT will be used to assess response in FDG-avid histologies using the 5-point scale. The product of the perpendicular diameters of a single node can be used to identify progressive disease. Routine surveillance scans are discouraged. These recommendations should improve evaluation of patients with lymphoma and enhance the ability to compare outcomes of clinical trials.
Uniformly adopted response criteria are essential for assessment of therapies incorporating conventional chemotherapy and chemoimmunotherapy regimens. Recently, immunomodulatory agents, such as ...immune checkpoint inhibitors, have demonstrated impressive activity in a broad range of lymphoma histologies. However, these agents may be associated with clinical and imaging findings during treatment suggestive of progressive disease (PD) despite evidence of clinical benefit (eg, tumor flare or pseudo-progression). Considering this finding as PD could lead to patients being prematurely removed from a treatment from which they actually stand to benefit. This phenomenon has been well described with checkpoint blockade therapy in solid tumors and anecdotally seen in lymphoma as well. To address this issue in the context of lymphoma immunomodulatory therapy, a workshop was convened to provide provisional recommendations to modify current response criteria in patients receiving these and future agents in clinical trials. The term “indeterminate response” was introduced to identify such lesions until confirmed as flare/pseudo-progression or true PD by either biopsy or subsequent imaging.
Positron emission tomography is established for staging and response evaluation in lymphoma using visual evaluation and semi‐quantitative analysis. Radiomic analysis involving quantitative imaging ...features at baseline, such as metabolic tumor volume and markers of disease dissemination and changes in the standardized uptake value during treatment are emerging as powerful biomarkers. The combination of radiomic features with clinical risk factors and genomic analysis offers the potential to improve clinical risk prediction. This review discusses the state of current knowledge, progress toward standardization of tumor delineation for radiomic analysis and argues that radiomic features, molecular markers and circulating tumor DNA should be included in clinical trial designs to enable the development of baseline and dynamic risk scores that could further advance the field to facilitate testing of novel treatments and personalized therapy in aggressive lymphomas.
Interim PET (iPET) assessment is important for response adaptation in Hodgkin lymphoma (HL). The current standard for iPET assessment is the Deauville score (DS). The aim of our study was to evaluate ...the causes of interobserver variability in assigning the DS for iPET in HL patients and to make suggestions for improvement.
All evaluable iPET scans from the RAPID study were re-read by two nuclear physicians, blinded to the results and patient outcomes in the RAPID trial. The iPET scans were assessed visually according to the DS and, thereafter, quantified using the qPET method. All discrepancies of more than one DS level were re-evaluated by both readers to find the reason for the discordant result.
In 249/441 iPET scans (56%) a concordant visual DS result was achieved. A "minor discrepancy" of one DS level occurred in 144 scans (33%) and a "major discrepancy" of more than one DS level in 48 scans (11%). The main causes for major discrepancies were 1) different interpretation of PET-positive lymph nodes-malignant vs. inflammatory; 2) lesions missed by one reader and 3) different assessment of lesions in activated brown fat tissue. In 51% of the minor discrepancy scans with residual lymphoma uptake, additional quantification resulted in a concordant quantitative DS result.
Discordant visual DS assessment occurred in 44% of all iPET scans. The main reason for major discrepancies was the different interpretation of PET positive lymph nodes as malignant or inflammatory. Disagreements in evaluation of the hottest residual lymphoma lesion can be solved by the use of semi-quantitative assessment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recent advances in imaging, use of prognostic indices, and molecular profiling techniques have the potential to improve disease characterization and outcomes in lymphoma. International trials are ...under way to test image-based response–adapted treatment guided by early interim positron emission tomography (PET)–computed tomography (CT). Progress in imaging is influencing trial design and affecting clinical practice. In particular, a five-point scale to grade response using PET-CT, which can be adapted to suit requirements for early- and late-response assessment with good interobserver agreement, is becoming widely used both in practice- and response-adapted trials. A workshop held at the 11th International Conference on Malignant Lymphomas (ICML) in 2011 concluded that revision to current staging and response criteria was timely.
An imaging working group composed of representatives from major international cooperative groups was asked to review the literature, share knowledge about research in progress, and identify key areas for research pertaining to imaging and lymphoma.
A working paper was circulated for comment and presented at the Fourth International Workshop on PET in Lymphoma in Menton, France, and the 12th ICML in Lugano, Switzerland, to update the International Harmonisation Project guidance regarding PET. Recommendations were made to optimize the use of PET-CT in staging and response assessment of lymphoma, including qualitative and quantitative methods.
This article comprises the consensus reached to update guidance on the use of PET-CT for staging and response assessment for 18Ffluorodeoxyglucose-avid lymphomas in clinical practice and late-phase trials.
PET with (18)F-FDG is a standard staging procedure for most lymphoma subtypes. Performed during and after therapy for Hodgkin lymphoma (HL) and aggressive non-Hodgkin lymphoma (NHL), (18)F-FDG PET ...results have a high prognostic value and correlate with survival. (18)F-FDG PET has been incorporated into revised response criteria for aggressive lymphomas, and several ongoing trials are under way to investigate the value of treatment adaptation based on early (18)F-FDG PET results for HL and aggressive NHL. There is little evidence to support the use of (18)F-FDG PET for monitoring of the treatment of indolent lymphomas and for routine use in the surveillance setting. So that trial results can be compared and translated easily into clinical practice, uniform and evidence-based guidelines for the interpretation and reporting of response monitoring scans are warranted. Because it is still not proven that the use of interim (18)F-FDG PET can improve patient outcomes, we recommend examination of the use of (18)F-FDG PET for response monitoring in appropriately designed clinical trials.
This Review focuses on the use of
F-fluorodeoxyglucose (
F-FDG) PET in the assessment of diffuse large B-cell lymphoma, follicular lymphoma, and peripheral T-cell lymphoma. PET is important for ...staging and prognostication with stage migration compared with CT. Better outcomes for patients with early stage diffuse large B-cell lymphoma and follicular lymphoma suggests better delineation of disease has translated to improved outcomes in such patients beyond simple stage migration. The aim of treatment of diffuse large B-cell lymphoma and peripheral T-cell lymphoma is potential cure, during which PET is mainly used to assess remission. Interim PET can assess chemosensitivity in these lymphomas, but it does not predict treatment success sufficiently well to enable treatment modification, particularly in the absence of more effective therapies for patients who remain PET-positive on interim scanning. In follicular lymphoma, traditionally viewed as an incurable lymphoma, the aim of treatment is to control disease for several years, while maintaining quality of life. PET can predict prognosis for patients with follicular lymphoma with high tumour burden at the end of induction chemotherapy, and it is being evaluated as a platform for response-adapted treatment of follicular lymphoma.
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