Response Assessment Criteria Research Articles

Longitudinal MRI evaluation of the efficacy of non-enhanced lung cancer brain metastases

Brain metastases (BM) are the most prevalent intracranial malignancies. Approximately 30–40% of cancer patients develop BM at some stage of their illness, presenting with a high incidence and poor prognosis. Our clinical findings indicate a significant disparity in the efficacy between non-enhanced and enhanced lung cancer BM. Therefore, the aim of this study is to conduct a longitudinal MRI evaluation of the therapeutic effect of non-enhanced lung cancer BM, thereby enabling improved efficacy prediction and more personalized treatment plans. We conducted a retrospective analysis of clinical and imaging data from 72 patients with lung cancer BM. Exclusion criteria included participants with a history of primary brain tumors, other malignancies, or neurological symptoms. We performed a longitudinal MRI evaluation of 8 patients with non-enhanced BM who met the eligibility criteria. The response to systemic therapy was locally assessed using the Neuro-Oncology response assessment criteria (RANO 2.0). A total of 8 patients were included in this study, comprising 4 cases of non-enhanced BM and 4 cases featuring both enhanced and non-enhanced BM. The median follow-up time for non-enhanced BM was 19 months, with a disease control rate of 50%. In contrast, the median progression-free follow-up time for enhanced BM was 35.5 months, yielding a disease control rate of 100%. After standardized treatment in accordance with clinical guidelines, patients with enhanced BM exhibited significantly better therapeutic outcomes than those with non-enhanced BM. Cases 1–4 demonstrated non-enhanced or mildly circular-enhanced lung cancer BM, with the sizes of all 4 lesions increasing by over 60% within approximately one year, indicating disease progression. In cases 5–8, each patient presented with two lesions: enhanced (Foci 1) and non-enhanced (Foci 2) BM. Comparative analysis of Foci 1 and Foci 2 revealed significantly weaker treatment responses in non-enhanced lesions (Patients 7–8), with Patient 5 exhibiting disease progression without any response. This study demonstrates that, following standardized treatment protocols aligned with clinical guidelines, the therapeutic effect of non-enhanced lung cancer BM is inferior to that of enhanced BM. Evaluating the enhancement type of lung cancer BM is essential for efficacy prediction and holds important implications for treatment guidance.

PSMA Radiotheranostics in Prostate Cancer: Principles, Practice, and Future Prospects.

Prostate cancer is a leading cause of cancer-related mortality in men, with metastatic castration-resistant prostate cancer presenting a substantial treatment challenge. The authors focuse on prostate-specific membrane antigen (PSMA) radiotheranostics, particularly lutetium 177 (177Lu)-PSMA radioligand therapy, as an emerging treatment modality for metastatic castration-resistant prostate cancer. The U.S. Food and Drug Administration approval of 177Lu-PSMA-617 marked a substantial advancement in the treatment paradigm of metastatic castration-resistant prostate cancer, based on the VISION trial that showed improved overall survival and quality of life compared with those for standard care. PSMA expression, assessed via PSMA PET, is crucial for patient selection and assessment of treatment eligibility. The authors discuss current practices, including therapy administration, dosing, and side effects, with a particular focus on eligibility criteria and the added value of posttherapy imaging. Response assessment criteria using PSMA PET are discussed, although these require further validation. The discussion of future directions highlights ongoing trials investigating PSMA targeting agents, the extension of radioligand therapy to earlier stages of prostate cancer, and combination therapies. This review underscores the role of PSMA radioligand therapy in the evolving landscape of prostate cancer treatment and its promise for improving patient outcomes. ©RSNA, 2024 Supplemental material is available for this article.

NIMG-51. PROSPECTIVE CASE CONTROL STUDY OF HYPOXIA FMISO PET/MRI AS A DIAGNOSTIC FEATURE OF GLIOBLASTOMA IMMUNOTHERAPY FAILURE

Abstract BACKGROUND Hypoxia is a prognostic biological feature of glioblastoma. 18F-fluoromisonidazole (FMISO) PET quantifies tumor hypoxia. Efficacy of checkpoint immunotherapy is being investigated, but specific response assessment criteria remain unknown. We hypothesized that tumor hypoxia is a defining feature of immunotherapy failure in patients with glioblastoma. METHODS A prospective case control study was undertaken in patients with newly diagnosed IDH wildtype glioblastoma (NCT03649880). Cases were concurrently enrolled in a phase II study (NCT03347617) of pembrolizumab immunotherapy (200 mg IV every 3 weeks) combined with Stupp protocol temozolomide-based chemoradiotherapy following maximal safe resection. Controls did not receive pembrolizumab. FMISO PET/MRI (3.7 MBq/kg, 90 min uptake) was performed at time of mRANO presumed progression. Hypoxic volume (HV) was defined by pixels with FMISO uptake ≥1.2x that of mean cerebellar uptake. MRI-Gd enhancing volume was segmented using a semi-automated approach. Hypoxic fraction (HF) was defined as the HV-to-MRI enhancing volume ratio. Disease progression or pseudoprogression (Psp) was confirmed through surgery or follow-up MRI. T-test and receiver operator characteristic (ROC) analysis assessed differences and diagnostic performance. RESULTS 18 patients (14 cases [11 progression and 3 Psp] and 4 controls [3 progression and 1 Psp]) provided evaluable disease. For all patients, HF was significantly elevated with progression (1.44 ± 0.8; N=14) compared to Psp (0.31 ± 0.3; N= 4; P=0.01). HV was not different (P=0.10). No difference in HV or HF was observed between Cases and Controls (P> 0.42). Use of HF yielded an AUROC of 0.96 with an optimal cut off of 0.74, to differentiate progression from Psp. CONCLUSION At mRANO presumed progression HF with FMISO PET/MRI accurately distinguishes tumor progression from neuroinflammatory Psp, irrespective of prior pembrolizumab immunotherapy. The incorporation of FMISO PET/MRI in larger prospective therapeutic clinical trials in patients with glioblastoma is underway and likely to improve response assessment criteria.

BIOM-75. MRI FLAIR SIGNAL ASSESSMENT IN NEURO-ONCOLOGY (SANO) AS A MEASURABLE TIMEPOINT FOR INTERVENTIONAL THERAPY PRIOR TO PROGRESSION IN HIGH GRADE GLIOMAS: A WINDOW OF OPPORTUNITY

Abstract BACKGROUND There are no validated clinical or radiographic assessments for response to therapy in glioblastoma (GBM). Offering interventions at the time of progression using our current assessment tools is likely too late as second-line therapies have failed to significantly delay progression and extend survival. In 2020, our team was first in the US to publish the largest and most comprehensive retrospective review identifying the T2/FLAIR MRI signal assessment protocol as an early indicator of progressive GBM. We proposed that the time of FLAIR signal abnormality within the resection cavity (RC) anticipated GBM progression by nearly 4 months and if used as a timepoint for therapeutic intervention could reshape glioma clinical trial design. METHODS To support validation of SANO, a prospective assessment of 146 GBM patients between 2019-2021 yielded 71 cases meeting resection and imaging inclusion criteria. We analyzed sequential brain MRIs from initial diagnosis to first progression for development of T2 FLAIR signal intensity (SI) within the RC as previously reported (Gatson et al 2020) and included cases with ventricle associated surgery as a comparator. PFS and OS were evaluated using Kaplan-Meier curves stratified by SI. RESULTS Development of SI occurred in 80.3% (n=57) GBM patients on average 2.8 months before RANO-assessed progression. A faster time to progression from SI development occurred in cases with ventricle associated RC. SI-positivity again portended poorer outcomes for PFS and OS as compared to SI-negative cases. Use of the eye (globe) for FLAIR assessment, instead of the ventricles, to qualitatively discern the presence of SI in ventricle associated RC. CONCLUSIONS This small prospective review supports our initial findings to validate a highly sensitive brain tumor imaging biomarker, SI, and should at least supplement existing response assessment criteria to improve declaration of GBM progression. Furthermore, use of SANO might also offer an earlier window of opportunity for salvage therapy intervention and offer new avenues for glioma clinical trial design.

NIMG-54. AUTOMATED IMAGING RESPONSE EVALUATION SYSTEM (AIRES) FOR NEURO-ONCOLOGY: PROTOTYPE SOFTWARE TOOL FOR DETERMINING STANDARDIZED RADIOGRAPHIC RESPONSE ASSESSMENT FOR GLIOBLASTOMA CLINICAL TRIALS

Abstract Standardized radiographic response assessment criteria like Modified Response Assessment in Neuro-Oncology (mRANO) and now the RANO 2.0 are utilized for evaluating progression-free survival and objective response rate during glioblastoma clinical trials. After measuring tumor size with either bidimensional diameters or volumetric segmentations, the crucial and final time-consuming step of categorizing progression, stable disease, and response based on multiple criteria and numerical thresholds (e.g. ≥40% volumetric growth = progressive disease) is currently done manually. We developed an application prototype, Automated Imaging Response Evaluation System (AIRES) for Neuro-Oncology, that uses the mRANO criteria to label each timepoint as treatment response, stable disease, or disease progression based on either bidimensional or volumetric measurements as well as optional inputs of clinical status and corticosteroid dosage. These inputs may be uploaded via CSV files, which can integrate with automated tumor segmentation volumetry workflows, or entered in the AIRES graphical user interface (GUI). The AIRES GUI displays a patient report consisting of a table and graph that contain the lesion size, percent change from baseline, percent change from nadir, and the mRANO response category for each timepoint. To test AIRES in a real-world application, tumor size measurements from 367 scans across 41 patients from NUTMEG, a phase II multicenter clinical trial, were used to perform mRANO reads and calculate progression-free survival and time to response. AIRES-assisted reads performed by reader 1 were significantly quicker than fully manual reads performed by reader 2 (37.1±8.6 vs 107.7±58.6 seconds, P<0.0001). These results show that the AIRES app can make the reads quicker and potentially feasible for non-trained personnel, while reducing the amount of error-prone manual steps. Additionally, the underlying logic of AIRES is easily adaptable to integrate other response criteria including but not limited to RANO 2.0 and other future response assessment updates.

NIMG-05. ARTIFICIAL INTELLIGENCE-BASED RESPONSE ASSESSMENT FOR PATIENTS RECEIVING LASER INTERSTITIAL THERMAL THERAPY

Abstract BACKGROUND Laser interstitial thermal therapy (LITT) is a minimally invasive option for tissue diagnosis, cytoreduction, and rapid post-operative return to systemic therapies for patients with brain tumors or radiation necrosis. As ablated tissue remains in situ, post-LITT edema may be associated with apparent increased lesion size and transient clinical worsening, complicating assessment of progression. METHODS All patients receiving LITT at a single center for tumors or radiation necrosis from 2015 – 2023 with ≥ 9 months of MRI follow-up were retrospectively reviewed. A 3D U-net segmentation model implemented in nnU-Net was developed for automated segmentation of Contrast-enhancing Lesion Volume (CeLV) of LITT-treated lesions on T1-weighted post-contrast MR images. CeLVs were analyzed to establish volumetric post-LITT response assessments. RESULTS Across 384 unique MRI exams, 61LITT-treated lesions and 6 control cases of medically-managed radiation necrosis were analyzed. Automated segmentation was qualitatively accurate in 367/384 (95.6%) images. CeLV increased to a median of 68.3% (IQR 35.1 – 109.2%) from baseline at 1 – 3 months from LITT (P = 0.0012) and returned to baseline thereafter. Based on established criteria, volumetric disease progression was defined as lesion expansion 40% from volumetric nadir or baseline. Twenty-one of 56 (37.5%) patients experienced volumetric progression with a progression-free survival of 21.4 (6.0 – 93.4) months. Patients experiencing volumetric progression had lower mOS (17.3 vs 62.1 months, P = 0.0015). CONCLUSIONS We observed a stereotyped increase in CeLV at 1 – 3 months post-LITT, which resolved within 6 months of the procedure. Post-LITT disease response can be reliably and feasibly assessed with criteria that account for this transient CeLV expansion. Automated lesion segmentation may speed adoption of volumetric response assessment criteria to clinical practice.

New clinical staging proposal applied to a Fabry cardiomyopathy cohort

Abstract Background Fabry disease (FD) is a rare cause of hypertrophic cardiomyopathy (HCM), and early diagnosis is important considering the response to enzyme replacement or chaperone therapies. Recently, a practical clinical staging for Fabry cardiomyopathy was proposed by Olivotto et al 2023, considering several features, being potentially useful for standardizing the criteria for initiation and response assessment to therapy. Imaging characterization of hypertrophy and fibrosis are critical key items to determine stages. This new proposal suggested 4 main stages (0, I, II, III) according to these parameters. Stages 0 and I are further divided in 2 sub-stages according to minor findings and hypertrophy severity, respectively. Unfortunately, not all patients with Fabry cardiomyopathy are identified early in the disease, limiting the response to treatment. Aim Our study aimed to evaluate retrospectively the staging of Fabry cardiomyopathy at first imaging cardiac evaluation according to the recent proposal (1), in a cohort of 35 patients with FD at a reference centre of Fabry disease. Results At the first cardiac evaluation, the group of patients had a median age of 46 years (28-68 years), 69% were female and 5% were already under enzymatic therapy. The majority of Fabry patients (66%) were in non-hypertrophic stage 0: 4 patients in 0A with no detected cardiac involvement and 19 patients in 0B with subclinical cardiac findings (17% presenting diastolic dysfunction, 14% impaired global longitudinal strain, 6% hypertrabeculation, 6% reduced native T1, 3% short PR duration, 3% cardiac symptoms). In hypertrophic stage I, 14% of patients were classified according to the presence and severity of LVH: 3 in IA (12-15 mm) and 2 in IB (>15mm). All patients (n=3, 9%) in hypertrophic fibrotic stage II presented non-extensive late enhancement (< 3 LV segments) in the first CMR. Patients with overt dysfunction or stage III (n=4; 11%), presented diffuse myocardial fibrosis (> 3 LV segments) or impaired systolic function (LVEF < 50%). Conclusion In our cohort patients, the new staging scheme allows us to identify and classify the different stages of FD cardiomyopathy. The majority of patients were unexpectedly identified in early disease stages, but that could be related to diagnosis in the context of familial screening. This proposal seems useful for clinical staging standardization to facilitate the evaluation of responses to treatments and to predict outcomes, however, needs to be validated in larger and prospective studies.

Clinical trial design for novel targeted agents in neuro-oncology.

Biomarker-based clinical trials investigating targeted treatments for brain tumors have surged due to better access to biomarker testing and a deeper grasp of the molecular basis of tumor development. The design of clinical trials is crucial for evaluating safety, confirming effectiveness, and affirming the clinical advantage of novel agents, with the goal of approval by regulatory authorities to expand patient treatment options. Given some challenges unique to brain tumors, early-stage clinical trials for novel targeted agents must integrate pharmacokinetics and tissue-based pharmacodynamic assessments to establish timely go-no-go decisions for larger studies. Surgical window-of-opportunity trials can allow for the comparison of treated and untreated tumor samples, verifying target engagement and its modulatory effects for evidence of biological activity. Due to the challenges of achieving the required sample sizes to power efficacy analyses, later-stage trials of targeted therapies can include basket trials which test one drug on multiple tumor types, while umbrella trials evaluate several biomarkers within a single histology. Platform trials can also be leveraged to investigate multiple biomarker-driven hypotheses within a unified protocol and can incorporate Bayesian algorithms for adaptive randomization. Selecting appropriate endpoints, such as progression-free survival or overall response rate, is crucial and novel response assessment criteria need to be considered in the context of the tumor and therapy being investigated. Lastly, inclusivity in trials is essential to address health disparities and engage diverse patient populations to ensure real-world impact. Future trials should build upon the knowledge gained from both initial achievements and past setbacks in the field.

140 Retrospective Evaluation of Response Assessment Criteria in Patients with Glioblastoma

140 Retrospective Evaluation of Response Assessment Criteria in Patients with Glioblastoma

ESR Essentials: response assessment criteria in oncologic imaging-practice recommendations by the European Society of Oncologic Imaging.

Assessing the response to oncological treatments is paramount for determining the prognosis and defining the best treatment for each patient. Several biomarkers, including imaging, can be used, but standardization is fundamental for consistency and reliability. Tumor response evaluation criteria have been defined by international groups for application in pharmaceutical clinical trials evaluating new drugs or therapeutic strategies. RECIST 1.1 criteria are exclusively based on unidimensional lesion measurements; changes in tumor size are used as surrogate imaging biomarkers to correlate with patient outcomes. However, increased tumor size does not always reflect tumor progression. The introduction of immunotherapy has led to the development of new criteria (iRECIST, Level of Evidence (LoE) Ib) that consider the possibility that an increase in disease burden is secondary to the immune response instead of progression, with the new concept of Unconfirmed Progressive Disease (a first progression event which must be confirmed on follow-up). Specific criteria were devised for HCC (mRECIST, LoE IV), which measure only enhancing HCC portions to account for changes after local therapy. For GIST treated with imatinib, criteria were developed to account for the possible increase in size reflecting a response rather than a progression by assessing both tumor size and density on CT (Choi, LoE II). This article provides concise and relevant practice recommendations aimed at general radiologists to help choose and apply the most appropriate criteria for assessing response to treatment in different oncologic scenarios. Though these criteria were developed for clinical trials, they may be applied in clinical practice as a guide for day-to-day interpretation. KEY POINTS: Response evaluation criteria, designed for use in clinical trials, might serve as a surrogate biomarker for overall survival. RECIST 1.1 defines measurable and non-measurable disease among which target lesions and non-target lesions are selected at baseline as reference for follow-ups. Some therapies and/or cancers require the use of different criteria, such as iRECIST, mRECIST, and Choi criteria.

Is it time to move from the Unidimensional RECIST 1.1 Response Assessment Criteria to a Volumetric Evaluation in the Present Era of Image-based Oncology? An Evaluation in Locally Advanced Head Neck Cancers Undergoing Treatment

AimsTumour response assessments, as per Response Evaluation Criteria in Solid Tumours (RECIST 1.1), are based on the sum of diameters (SODs) of the primary tumour (longest diameter) and/or short axis diameter of lymph nodes. This study evaluates the response categorisation as per RECIST 1.1 vs Computed tomography (CT) based volumetric assessment of RECIST (proposed as vRECIST) in locally advanced head and neck cancers (LAHNCs) undergoing treatment. Material and methodsThe pre-treatment SODs and CT estimated tumour volumes were recorded in 45 LAHNCs treated with radiotherapy (RT), chemoradiotherapy (CTRT) or thermochemoradiotherapy (HTCTRT). Tumour responses were assessed independently as per RECIST 1.1 and vRECIST by two radiation oncologists and grouped into complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD). These response groups were evaluated for the likely congruence of the two approaches, as categorised independently by these two observers. ResultsAll patients in stages III (n = 7), IVA (n = 16) and IVB (n = 22) were inoperable and had received either RT alone (n = 1), CTRT (n = 12) or HTCTRT (n = 32). Based on SODs criteria of RECIST 1.1, of the 45 patients, 5 and 40 were grouped as PR and SD by the first observer, while this changed to 34 and 10, respectively and 1 PD, with vRECIST (p < 0.001). Similarly, for the second observer, the 4 PR and 41 SD grouped using RECIST 1.1 were recategorised to 34 PR, 10 SD, and 1 PD by vRECIST (p < 0.001). Thus, a mismatch of 66.6% and 68.8%, respectively, was evident by observers first and second in categorising SD based on SODs of RECIST 1.1 vs PR on vRECIST. ConclusionsTreatment responses in LAHNCs assessed using SODs resulted in significant uncertainties and failed to reflect actual volumetric changes in tumours during treatment. It is perhaps time to consider replacing the SODs of RECIST 1.1 with vRECIST for unequivocal tumour response categorisation in the present era of image-based oncology practice.

Concordance between physician response assessment and a novel method per Lugano criteria in patients with lymphoma using real-world data.

e19082 Background: Clinical response assessment criteria, such as RECIST v1.1 and Lugano 2014, provide a standardized approach to assess treatment effectiveness in oncology clinical trials. Corresponding methodologies are needed for real-world data (RWD) to improve interpretability alongside clinical trial data and facilitate replication of results across RWD studies. We developed a RWD novel methodology, real-world Lugano (rwLugano), derived from Lugano 2014 criteria to classify lymphoma treatment response among patients with diffuse large B-cell lymphoma (DLBCL). Methods: A retrospective multisite RWD study identified adult patients with DLBCL treated with first line chemoimmunotherapy in US clinical practice (01JAN2015-31DEC2022). Participating sites abstracted clinical data via medical chart review and positron emission tomography-computed tomography (PET-CT) reports. Deidentified digital PET-CTs taken at treatment initiation and first response assessment were uploaded for BICR. Three distinct methods were used to assess treatment response: 1) physician-reported obtained from unstructured clinical notes in medical records, 2) rwLugano calculated using data (i.e., components of Lugano 2014) from PET-CT reports, and 3) BICR adjudication by two lymphoma radiologists using Lugano 2014 criteria. We compared the proportion of patients by response category: complete (CR), partial (PR), stable (SD) and progressive (PD) for each method. Analyses included agreement (%), concordance (Cohen’s kappa [κ]), and odds ratios with 95% confidence interval (OR; 95%CI) estimated using multivariable generalized linear mixed models (GLMM) adjusted for baseline characteristics. Results: The study identified 174 patients with DLBCL (female n=71 [41%]; white n=135 [78%]; Hispanic n=13 [7%]; mean age 66 years). Fewer patients were classified as CR at initial response via physician-reported response (n=111, 64%) compared to rwLugano (n=145, 83%), and BICR (n=142, 82%). Overall and CR agreement with BICR (see Table) was higher for rwLugano (overall: 83%, κ=0.49; CR: 86%, κ=0.50) than physician-charted response (overall: 72%, κ=0.45; CR: 76%, κ=0.43). In GLMM models, physician-charted response underestimated CR compared to BICR (OR=0.22, 95%CI:0.12-0.43), whereas rwLugano was statistically similar to BICR (OR=1.2, 95%CI:0.6-2.4). Conclusions: This study found that physician-reported response may underestimate CR at initial response, and rwLugano may be more consistent with BICR for treatment response assessment. Use of rwLugano warrants further evaluation as a methodology to assess treatment response in RWD lymphoma research. [Table: see text]

Monitoring Response and Resistance to Treatment in Chronic Lymphocytic Leukemia.

The recent evolution in chronic lymphocytic leukemia (CLL) targeted therapies led to a progressive change in the way clinicians manage the goals of treatment and evaluate the response to treatment in respect to the paradigm of the chemoimmunotherapy era. Continuous therapies with BTK inhibitors achieve prolonged and sustained control of the disease. On the other hand, venetoclax and anti-CD20 monoclonal antibodies or, more recently, ibrutinib plus venetoclax combinations, given for a fixed duration, achieve undetectable measurable residual disease (uMRD) in the vast majority of patients. On these grounds, a time-limited MRD-driven strategy, a previously unexplored scenario in CLL, is being attempted. On the other side of the spectrum, novel genetic and non-genetic mechanisms of resistance to targeted treatments are emerging. Here we review the response assessment criteria, the evolution and clinical application of MRD analysis and the mechanisms of resistance according to the novel treatment strategies within clinical trials. The extent to which this novel evidence will translate in the real-life management of CLL patients remains an open issue to be addressed.

State-of-the-Art Hybrid Imaging of Neuroendocrine Neoplasms.

Neuroendocrine neoplasms (NENs) may be challenging to diagnose due to their small size and diverse anatomical locations. Hybrid imaging techniques, specifically positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI), represent the current state-of-the-art for evaluating NENs. The preferred radiopharmaceuticals for NEN PET imaging are gallium-68 (68Ga) DOTA-peptides, which target somatostatin receptors (SSTR) overexpressed on NEN cells. Clinical applications of [68Ga]Ga-DOTA-peptides PET/CT include diagnosis, staging, prognosis assessment, treatment selection, and response evaluation. Fluorodeoxyglucose-18 (18F-FDG) PET/CT aids in detecting low-SSTR-expressing lesions and helps in patient stratification and treatment planning, particularly in grade 3 neuroendocrine tumors (NETs). New radiopharmaceuticals such as fluorine-labeled SSTR agonists and SSTR antagonists are emerging as alternatives to 68Ga-labeled peptides, offering improved detection rates and favorable biodistribution. The maturing of PET/MRI brings advantages to NEN imaging, including simultaneous acquisition of PET and MRI images, superior soft tissue contrast resolution, and motion correction capabilities. The PET/MRI with [68Ga]Ga-DOTA-peptides has demonstrated higher lesion detection rates and more accurate lesion classification compared to PET/CT. Overall, hybrid imaging offers valuable insights in the diagnosis, staging, and treatment planning of NENs. Further research is needed to refine response assessment criteria and standardize reporting guidelines.

Total metabolic tumor volume on 18F-FDG PET/CT is a game-changer for patients with metastatic lung cancer treated with immunotherapy

PurposeBecause of atypical response imaging patterns in patients with metastatic non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICPIs), new biomarkers are needed for a better monitoring of...

Assessment of perineural spread in advanced cutaneous squamous cell carcinomas treated with immunotherapy

BackgroundCutaneous squamous cell carcinoma (CSCC) has a propensity for perineural spread (PNS) which is associated with poorer treatment outcomes. Immunotherapy is the new standard of care treatment for advanced CSCC resulting in durable responses. PNS is not captured by traditional response assessment criteria used in clinical trials, e.g. RECIST 1.1, and there is limited literature documenting radiological PNS responses to immunotherapy. In this study we assess PNS responses to immunotherapy using a modified grading system.MethodsThis is an Australian single-center retrospective review of patients with advanced CSCC who were treated with immunotherapy between April 2018 and February 2022 who had evidence of PNS on pre-treatment magnetic-resonance imaging (MRI). The primary outcome was blinded overall radiological response in PNS using graded radiological criteria, post-commencement of immunotherapy. Three defined timepoints (< 5 months, 5–10 months, > 10 months) were reviewed. Secondary outcomes included a correlation between RECIST 1.1 and PNS assessments and the assessment of PNS on fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT).ResultsTwenty CSCC patients treated with immunotherapy were identified. Median age was 75.7 years and 75% (n = 15) were male. All patients had locoregionally advanced disease and no distant metastases. Median follow-up was 18.5 months (range: 2–59). 70% (n = 14) demonstrated a PNS response by 5 months. Three patients experienced pseudoprogression. One patient had PNS progression by the end of study follow up. RECIST 1.1 and PNS responses were largely concordant at > 10 months (Cohen’s Kappa 0.62). 5/14 cases had features suspicious for PNS on FDG-PET/CT.ConclusionsPNS response to immunotherapy can be documented on MRI using graded radiological criteria. High response rates were seen in PNS with the use of immunotherapy in this cohort and these responses were largely concordant with RECIST 1.1 assessments. FDG-PET/CT demonstrated limited sensitivity in the detection of PNS.

Advanced Imaging in the Diagnosis and Response Assessment of High-Grade Glioma: AJR Expert Panel Narrative Review.

This AJR Expert Panel Narrative explores the current status of advanced MRI and PET techniques for the post-therapeutic response assessment of high-grade adult-type gliomas, focusing on ongoing clinical controversies in current practice. Discussed techniques that complement conventional MRI and aid the differentiation of recurrent tumor from post-treatment effects include DWI and diffusion tensor imaging; perfusion MRI techniques including dynamic susceptibility contrast (DSC), dynamic contrast-enhanced MRI, and arterial spin labeling; MR spectroscopy including assessment of 2-hydroxyglutarate (2HG) concentration; glucose- and amino acid (AA)-based PET; and amide proton transfer imaging. Updated criteria for Response Assessment in Neuro-Oncology are presented. Given the abundant supporting clinical evidence, the panel supports a recommendation that routine response assessment after HGG treatment should include perfusion MRI, particularly given the development of a consensus recommended DSC-MRI protocol. Although published studies support 2HG MRS and AA PET, these techniques' widespread adoption will likely require increased availability (for 2HG MRS) or increased insurance funding in the United States (for AA PET). The article concludes with a series of consensus opinions from the author panel, centered on the clinical integration of the advanced imaging techniques into posttreatment surveillance protocols.

Differences and Common Ground in 177Lu-PSMA Radioligand Therapy Practice Patterns: International Survey of 95 Theranostic Centers.

177Lu-labeled prostate-specific membrane antigen (PSMA) radioligand therapy effectively treats metastatic castration-resistant prostate cancer. Patients requiring treatment, and consequently the number of theranostic centers, are expected to increase significantly after Food and Drug Administration and European Medicines Agency approval. This requires standardization or harmonization among theranostic centers. The aim of this study was to assess operational differences and similarities among 177Lu-PSMA treatment centers. Methods: A questionnaire comprising 62 items, designed by a core team of 5 physicians and externally reviewed by international experts, was developed. Study participants were asked to provide answers about their center, patient selection, radiopharmaceuticals, clinical assessment before and after 177Lu-PSMA treatments, laboratory values, treatment discontinuation, posttreatment imaging, and general information. An invitation e-mail to participate in the study was sent in June 2022. Duplicates were removed to allow for only one valid response per center. Results: Ninety-five of 211 (45%) contacted centers completed the questionnaire. Most participating centers were in Europe (51%), followed by America (22%) and Asia (22%). During the 12 mo before this study, a total of 5,906 patients received 177Lu-PSMA therapy at the 95 participating centers. Most of these patients were treated in Europe (2,840/5,906; 48%), followed by Asia (1,313/5,906; 22%) and Oceania (1,225/5,906; 21%). PSMA PET eligibility for 177Lu-PSMA was determined most frequently using 68Ga-PSMA-11 (77%). Additional pretherapy imaging included 18F-FDG PET/CT, CT, renal scintigraphy, and bone scintigraphy at 41 (49%), 27 (32%), 25 (30%), and 13 (15%), respectively, of the 84 centers for clinical standard of care, compassionate care, or local research protocols and 11 (26%), 25 (60%), 9 (21%), and 28 (67%), respectively, of the 42 centers for industry-sponsored trials. PSMA PET eligibility criteria included subjective qualitative assessment of PSMA positivity at 33% of centers, VISION criteria at 23%, and TheraP criteria at 13%. The mean standard injected activity per cycle was 7.3 GBq (range, 5.5-11.1 GBq). Sixty-two (65%) centers applied standardized response assessment criteria, and PSMA PET Progression Criteria were the most applied (37%). Conclusion: Results from this international survey revealed interinstitutional differences in several aspects of 177Lu-PSMA radionuclide therapy, including patient selection, administered activity, and the response assessment strategy. Standardization or harmonization of protocols and dedicated training are desirable in anticipation of increasing numbers of patients and theranostic centers.

Updated Response Assessment in Neuro-Oncology (RANO) for Gliomas.

The response assessment in Neuro-Oncology (RANO) criteria and its versions were developed by expert opinion consensus to standardize response evaluation in glioma clinical trials. New patient-based data informed the development of updated response assessment criteria, RANO 2.0. In a recent study of patients with glioblastoma, the post-radiation brain MRI was a superior baseline MRI compared to the pretreatment MRI, and confirmation scans were only beneficial within the first 12weeks of completion of radiation in newly diagnosed disease. Nonenhancing disease evaluation did not improve the correlation between progression-free survival and overall survival in newly diagnosed and recurrent settings. RANO 2.0 recommends a single common response criteria for high- and low-grade gliomas, regardless of the treatment modality being evaluated. It also provides guidance on the evaluation of nonenhancing tumors and tumors with both enhancing and nonenhancing components.

Automated segmentation of ablated lesions using deep convolutional neural networks: A basis for response assessment following laser interstitial thermal therapy.

Laser interstitial thermal therapy (LITT) of intracranial tumors or radiation necrosis enables tissue diagnosis, cytoreduction, and rapid return to systemic therapies. Ablated tissue remains in situ, resulting in characteristic post-LITT edema associated with transient clinical worsening and complicating post-LITT response assessment. All patients receiving LITT at a single center for tumors or radiation necrosis from 2015 to 2023 with ≥9 months of MRI follow-up were included. An nnU-Net segmentation model was trained to automatically segment contrast-enhancing lesion volume (CeLV) of LITT-treated lesions on T1-weighted images. Response assessment was performed using volumetric measurements. Three hundred and eighty four unique MRI exams of 61 LITT-treated lesions and 6 control cases of medically managed radiation necrosis were analyzed. Automated segmentation was accurate in 367/384 (95.6%) images. CeLV increased to a median of 68.3% (IQR 35.1-109.2%) from baseline at 1-3 months from LITT (P = 0.0012) and returned to baseline thereafter. Overall survival (OS) for LITT-treated patients was 39.1 (9.2-93.4) months. Lesion expansion above 40% from volumetric nadir or baseline was considered volumetric progression. Twenty-one of 56 (37.5%) patients experienced progression for a volumetric progression-free survival of 21.4 (6.0-93.4) months. Patients with volumetric progression had worse OS (17.3 vs 62.1 months, P = 0.0015). Post-LITT CeLV expansion is quantifiable and resolves within 6 months of LITT. Development of response assessment criteria for LITT-treated lesions is feasible and should be considered for clinical trials. Automated lesion segmentation could speed the adoption of volumetric response criteria in clinical practice.