Detection of immune-related adverse events by medical imaging in patients treated with anti-programmed cell death 1

Double Whammy: A Case Report of Immune Checkpoint Inhibitor Colitis and Concomitant Cytomegalovirus Colitis in a Patient on Nivolumab

Immune checkpoint inhibitors commonly cause gastrointestinal immune-related adverse effects. These patients also carry an increased risk of concomitant infections. This 66-year-old man with immune checkpoint inhibitor colitis was discovered to have concurrent Yersinia and Cytomegalovirus colitis. Such infections may mimic or complicate disease course. Hence, clinicians must monitor patient symptoms, have a low threshold for infectious testing and colonoscopy, and consider treatment strategies to mitigate their risk.

Hepatotoxicity in Cancer Immunotherapy: Diagnosis, Management, and Future Perspectives

Cancer immunotherapy, particularly immune checkpoint inhibitors, has positively impacted oncological treatments. Despite its effectiveness, immunotherapy is associated with immune-related adverse events (irAEs) that can affect any organ, including the liver. Hepatotoxicity primarily manifests as immune-related hepatitis and, less frequently, cholangitis. Several risk factors, such as pre-existing autoimmune and liver diseases, the type of immunotherapy, and combination regimens, play a role in immune-related hepatotoxicity (irH), although reliable predictive markers or models are still lacking. The severity of irH ranges from mild to severe cases, up to, in rare instances, acute liver failure. Management strategies require regular monitoring for early diagnosis and interventions, encompassing strict monitoring for mild cases to the permanent suspension of immunotherapy for severe forms. Corticosteroids are the backbone of treatment in moderate and high-grade damage, alone or in combination with additional immunosuppressive drugs for resistant or refractory cases. Given the relatively low number of events and the lack of dedicated prospective studies, much uncertainty remains about the optimal management of irH, especially in the most severe cases. This review presents the main features of irH, focusing on injury patterns and mechanisms, and provides an overview of the management landscape, from standard care to the latest evidence.

18 F-FDG PET/CT for Detection of Immunotherapy-Induced Hypophysitis-A Case-Control Study

PURPOSE

Hypophysitis occurs in up to 10% of patients treated with immune-checkpoint inhibitors (ICIs). MRI shows no abnormalities of the pituitary gland in one third of patients. A delayed diagnosis increases the risk for life-threatening adrenal crisis, underscoring the need for early detection. This study evaluates the diagnostic accuracy FDG PET/CT in detecting ICI-induced hypophysitis in a cohort of melanoma patients.

MATERIALS AND METHODS

Patients with metastatic melanoma and ICI-induced hypophysitis, who underwent FDG PET/CT 90 days before to 10 days after diagnosis, were compared with an age- and sex-matched control group of patients undergoing ICI treatment without signs of hypophysitis. The ratio of SUV max of the pituitary gland to the SUV mean of the blood pool (target-to-background ratio [TBR]) was calculated. Diagnostic accuracy of the TBR was assessed using area under the receiver operating characteristics curve analysis.

RESULTS

A total of 28 patients was included. The majority of patients with hypophysitis received ipilimumab/nivolumab (64.3%, 9/14). Visual assessment of the TBR distribution demonstrated a positive correlation with decreasing time to diagnosis. To evaluate diagnostic performance, only patients with FDG PET/CT 50 days before to 8 days after diagnosis (11/14) were included. TBR was significantly higher in these compared with the control group (median [interquartile range], 2.78 [2.41] vs 1.59 [0.70], respectively; P = 0.034). A sensitivity of 72.7% and a specificity of 90.9% were achieved at a TBR threshold of 2.41 (area under the receiver operating characteristics curve = 0.769).

CONCLUSIONS

Our findings suggest that, in patients undergoing ICI treatment for metastatic melanoma, a pituitary TBR of approximately 2.4 may indicate impending ICI-induced hypophysitis.

Incidence of thyroid dysfunction caused by immune checkpoint inhibitors combined with chemotherapy: A systematic review and meta-analysis

BACKGROUND

The combination of immune checkpoint inhibitors (ICIs) and chemotherapy as a first-line treatment for triple-negative breast cancer (TNBC) has been associated with many adverse reactions. Thyroid dysfunction, the most common adverse reaction of the endocrine system, has also attracted significant attention. This study aimed to analyse the effect of ICIs combined with chemotherapy on thyroid function in patients with TNBC.

METHODS

As of November 4, 2023, we searched the PubMed, Web of Science, and Cochrane Library databases for clinical trials of ICIs combined with chemotherapy for the treatment of TNBC. The incidence of hypothyroidism and hyperthyroidism was calculated using a random-effects model.

RESULTS

In the final analysis, 3,226 patients from 19 studies were included. The total incidence of all-grade hypothyroidism induced by the combination of ICIs and chemotherapy in treating TNBC (12% (95% confidence intervals(CI): 0.10-0.15)) was higher than that of hyperthyroidism (5% (95% CI: 0.04-0.06)). Pembrolizumab combined with chemotherapy caused the highest incidence of all grades of hypothyroidism for 13% (95% CI: 0.05-0.06). Durvalumab combined with chemotherapy caused the highest incidence of all grades of hyperthyroidism, at 7% (95% CI: 0.03-0.11). ICIs combined with chemotherapy caused a higher incidence of all grades of hypothyroidism in advanced TNBC (15% (95% CI: 0.13-0.17)) than in early stage TNBC (10% (95% CI: 0.07-0.13)).

CONCLUSION

In TNBC, the incidence of hypothyroidism caused by the combination of ICIs and chemotherapy was significantly higher than that caused by hyperthyroidism. Pembrolizumab combined with chemotherapy resulted in the highest incidence of hypothyroidism. The incidence of hypothyroidism in patients with advanced TNBC was significantly higher than that in patients with early stage TNBC. In addition, ICIs combined with chemotherapy resulted in 16 out of 3,226 patients experiencing grade ≥ 3 thyroid dysfunction. Although the incidence of severe thyroid dysfunction is low, it requires attention.

PROSPERO

CRD42023477933.

Ultrasound Imaging of Tumor Vascular CD93 with MMRN2 Modified Microbubbles for Immune Microenvironment Prediction

Vascular microenvironment is found to be closely related to immunotherapy efficacy. Identification and ultrasound imaging of the unique vascular characteristics, able to predict immune microenvironment, is important for immunotherapy decision-making. Herein, it is proved that high CD93 expression in the tumor vessels is closely related to the poor immune response of prostate cancer. For ultrasound molecular imaging of CD93, CD93-targeted microbubbles (MBs) consist a gaseous core and the MMRN2 (Multimerin-2) containing cell membrane (CM) /lipid hybrid membrane is then synthesized. In vitro and in vivo assays demonstrate that these MBs can recognize CD93 efficiently and then accumulate within tumor regions highly expressing CD93. Contrast-enhanced ultrasound (CEUS) imaging with CD93-targeted MBs demonstrates that targeted ultrasound intensity is negatively related to inflammatory tumor immune microenvironment (TIME) and cytotoxic T cell infiltration. Together, endothelial expression of CD93 in tumor is a unique predictor of immunosuppressive microenvironment and CD93-targeted MBs have a great potential to evaluate tumor immune status.

Integrating Artificial Intelligence and PET Imaging for Drug Discovery: A Paradigm Shift in Immunotherapy

The integration of artificial intelligence (AI) and positron emission tomography (PET) imaging has the potential to become a powerful tool in drug discovery. This review aims to provide an overview of the current state of research and highlight the potential for this alliance to advance pharmaceutical innovation by accelerating the development and deployment of novel therapeutics. We previously performed a scoping review of three databases (Embase, MEDLINE, and CENTRAL), identifying 87 studies published between 2018 and 2022 relevant to medical imaging (e.g., CT, PET, MRI), immunotherapy, artificial intelligence, and radiomics. Herein, we reexamine the previously identified studies, performing a subgroup analysis on articles specifically utilizing AI and PET imaging for drug discovery purposes in immunotherapy-treated oncology patients. Of the 87 original studies identified, 15 met our updated search criteria. In these studies, radiomics features were primarily extracted from PET/CT images in combination (n = 9, 60.0%) rather than PET imaging alone (n = 6, 40.0%), and patient cohorts were mostly recruited retrospectively and from single institutions (n = 10, 66.7%). AI models were used primarily for prognostication (n = 6, 40.0%) or for assisting in tumor phenotyping (n = 4, 26.7%). About half of the studies stress-tested their models using validation sets (n = 4, 26.7%) or both validation sets and test sets (n = 4, 26.7%), while the remaining six studies (40.0%) either performed no validation at all or used less stringent methods such as cross-validation on the training set. Overall, the integration of AI and PET imaging represents a paradigm shift in drug discovery, offering new avenues for more efficient development of therapeutics. By leveraging AI algorithms and PET imaging analysis, researchers could gain deeper insights into disease mechanisms, identify new drug targets, or optimize treatment regimens. However, further research is needed to validate these findings and address challenges such as data standardization and algorithm robustness.

A comparison of 18 F-FDG PET-based radiomics and deep learning in predicting regional lymph node metastasis in patients with resectable lung adenocarcinoma: a cross-scanner and temporal validation study

OBJECTIVE

The performance of 18 F-FDG PET-based radiomics and deep learning in detecting pathological regional nodal metastasis (pN+) in resectable lung adenocarcinoma varies, and their use across different generations of PET machines has not been thoroughly investigated. We compared handcrafted radiomics and deep learning using different PET scanners to predict pN+ in resectable lung adenocarcinoma.

METHODS

We retrospectively analyzed pretreatment 18 F-FDG PET from 148 lung adenocarcinoma patients who underwent curative surgery. Patients were separated into analog (n = 131) and digital (n = 17) PET cohorts. Handcrafted radiomics and a ResNet-50 deep-learning model of the primary tumor were used to predict pN+ status. Models were trained in the analog PET cohort, and the digital PET cohort was used for cross-scanner validation.

RESULTS

In the analog PET cohort, entropy, a handcrafted radiomics, independently predicted pN+. However, the areas under the receiver-operating-characteristic curves (AUCs) and accuracy for entropy were only 0.676 and 62.6%, respectively. The ResNet-50 model demonstrated a better AUC and accuracy of 0.929 and 94.7%, respectively. In the digital PET validation cohort, the ResNet-50 model also demonstrated better AUC (0.871 versus 0.697) and accuracy (88.2% versus 64.7%) than entropy. The ResNet-50 model achieved comparable specificity to visual interpretation but with superior sensitivity (83.3% versus 66.7%) in the digital PET cohort.

CONCLUSION

Applying deep learning across different generations of PET scanners may be feasible and better predict pN+ than handcrafted radiomics. Deep learning may complement visual interpretation and facilitate tailored therapeutic strategies for resectable lung adenocarcinoma.

Integrating [18F]-Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography with Radiation Therapy and Immunomodulation in Precision Therapy for Solid Tumors

[18F]-FDG positron emission tomography with computed tomography (PET/CT) imaging is widely used to enhance the quality of care in patients diagnosed with cancer. Furthermore, it holds the potential to offer insight into the synergic effect of combining radiation therapy (RT) with immuno-oncological (IO) agents. This is achieved by evaluating treatment responses both at the RT and distant tumor sites, thereby encompassing the phenomenon known as the abscopal effect. In this context, PET/CT can play an important role in establishing timelines for RT/IO administration and monitoring responses, including novel patterns such as hyperprogression, oligoprogression, and pseudoprogression, as well as immune-related adverse events. In this commentary, we explore the incremental value of PET/CT to enhance the combination of RT with IO in precision therapy for solid tumors, by offering supplementary insights to recently released joint guidelines.

Image-Guided Precision Medicine in the Diagnosis and Treatment of Pheochromocytomas and Paragangliomas

In this comprehensive review, we aimed to discuss the current state-of-the-art medical imaging for pheochromocytomas and paragangliomas (PPGLs) diagnosis and treatment. Despite major medical improvements, PPGLs, as with other neuroendocrine tumors (NETs), leave clinicians facing several challenges; their inherent particularities and their diagnosis and treatment pose several challenges for clinicians due to their inherent complexity, and they require management by multidisciplinary teams. The conventional concepts of medical imaging are currently undergoing a paradigm shift, thanks to developments in radiomic and metabolic imaging. However, despite active research, clinical relevance of these new parameters remains unclear, and further multicentric studies are needed in order to validate and increase widespread use and integration in clinical routine. Use of AI in PPGLs may detect changes in tumor phenotype that precede classical medical imaging biomarkers, such as shape, texture, and size. Since PPGLs are rare, slow-growing, and heterogeneous, multicentric collaboration will be necessary to have enough data in order to develop new PPGL biomarkers. In this nonsystematic review, our aim is to present an exhaustive pedagogical tool based on real-world cases, dedicated to physicians dealing with PPGLs, augmented by perspectives of artificial intelligence and big data.

Adverse Effects of Immune-Checkpoint Inhibitors: A Comprehensive Imaging-Oriented Review

Immune-checkpoint inhibitors (ICIs) are immunomodulatory monoclonal antibodies, which increase antitumor immunity of the host and facilitate T-cell-mediated actions against tumors. These medications have been used in recent years as a weapon against advanced stage malignancies, such as melanoma, renal cell carcinoma, lymphoma, small or non-small cell lung cancer, and colorectal cancer. Unfortunately, they are not free from possible adverse effects (immune-related adverse events-irAEs) that mainly affect skin, gastrointestinal, hepatic, and endocrine systems. Early diagnosis of irAEs is essential to correctly and rapidly manage patients, with ICIs suspension and therapies administration. Deep knowledge of the imaging and clinical patterns of irAEs is the key to promptly rule out other diagnoses. Here, we performed a review of the radiological signs and differential diagnosis, based on the organ involved. The aim of this review is to provide guidance to recognize the most significant radiological findings of the main irAEs, based on incidence, severity, and the role of imaging.

Retroperitoneal Inflammation Detected on FDG PET/CT in Patient on Long-Term Immunotherapy

ABSTRACT

A 68-year-old man with a history of pulmonary adenocarcinoma on maintenance pembrolizumab presented for surveillance imaging. 18 F-FDG PET/CT demonstrated new ill-defined right retroperitoneal and presacral soft tissue stranding with associated FDG uptake suggestive of inflammation. Biopsy results revealed fibroadipose tissue with extensive lymphoplasmacytic inflammation concerning for immunotherapy-related toxicity. The patient was subsequently taken off pembrolizumab, which he had been on for approximately 3 years. Recognition of immunotherapy-related adverse effects and how they can manifest on 18 F-FDG PET/CT is important for prompt cessation of treatment.

Positron emission tomography molecular imaging to monitor anti-tumor systemic response for immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) achieve a milestone in cancer treatment. Despite the great success of ICI, ICI therapy still faces a big challenge due to heterogeneity of tumor, and therapeutic response is complicated by possible immune-related adverse events (irAEs). Therefore, it is critical to assess the systemic immune response elicited by ICI therapy to guide subsequent treatment regimens. Positron emission tomography (PET) molecular imaging is an optimal approach in cancer diagnosis, treatment effect evaluation, follow-up, and prognosis prediction. PET imaging can monitor metabolic changes of immunocytes and specifically identify immuno-biomarkers to reflect systemic immune responses. Here, we briefly review the application of PET molecular imaging to date of systemic immune responses following ICI therapy and the associated rationale.

Radiomics-guided checkpoint inhibitor immunotherapy for precision medicine in cancer: A review for clinicians

Immunotherapy using immune checkpoint inhibitors (ICIs) is a breakthrough in oncology development and has been applied to multiple solid tumors. However, unlike traditional cancer treatment approaches, immune checkpoint inhibitors (ICIs) initiate indirect cytotoxicity by generating inflammation, which causes enlargement of the lesion in some cases. Therefore, rather than declaring progressive disease (PD) immediately, confirmation upon follow-up radiological evaluation after four-eight weeks is suggested according to immune-related Response Evaluation Criteria in Solid Tumors (ir-RECIST). Given the difficulty for clinicians to immediately distinguish pseudoprogression from true disease progression, we need novel tools to assist in this field. Radiomics, an innovative data analysis technique that quantifies tumor characteristics through high-throughput extraction of quantitative features from images, can enable the detection of additional information from early imaging. This review will summarize the recent advances in radiomics concerning immunotherapy. Notably, we will discuss the potential of applying radiomics to differentiate pseudoprogression from PD to avoid condition exacerbation during confirmatory periods. We also review the applications of radiomics in hyperprogression, immune-related biomarkers, efficacy, and immune-related adverse events (irAEs). We found that radiomics has shown promising results in precision cancer immunotherapy with early detection in noninvasive ways.

The combined tumor-nodal glycolytic entropy improves survival stratification in nonsmall cell lung cancer with locoregional disease

OBJECTIVE

To investigate whether combining primary tumor and metastatic nodal glycolytic heterogeneity on 18 F-fluorodeoxyglucose PET ( 18 F-FDG PET) improves prognostic prediction in nonsmall cell lung cancer (NSCLC) with locoregional disease.

METHODS

We retrospectively analyzed 18 F-FDG PET-derived features from 94 patients who had undergone curative treatments for regional nodal metastatic NSCLC. Overall survival (OS) and progression-free survival (PFS) were analyzed using univariate and multivariate Cox regression models. We used the independent prognosticators to construct models to predict survival.

RESULTS

Combined entropy (entropy derived from the combination of the primary tumor and metastatic nodes) and age independently predicted OS (both P = 0.008) and PFS ( P = 0.007 and 0.050, respectively). At the same time, the Eastern Cooperative Oncology Group status was another independent risk factor for unfavorable OS ( P = 0.026). Our combined entropy-based models outperformed the traditional staging system (c-index = 0.725 vs. 0.540, P < 0.001 for OS; c-index = 0.638 vs. 0.511, P = 0.003 for PFS) and still showed prognostic value in subgroups according to sex, histopathology, and different initial curative treatment strategies.

CONCLUSION

Combined primary tumor-nodal glycolytic heterogeneity independently predicted survival outcomes. In combination with clinical risk factors, our models provide better survival predictions and may enable tailored treatment strategies for NSCLC with locoregional disease.

Emerging and Evolving Concepts in Cancer Immunotherapy Imaging

Criteria based on measurements of lesion diameter at CT have guided treatment with historical therapies due to the strong association between tumor size and survival. Clinical experience with immune checkpoint modulators shows that editing immune system function can be effective in various solid tumors. Equally, novel immune-related phenomena accompany this novel therapeutic paradigm. These effects of immunotherapy challenge the association of tumor size with response or progression and include risks and adverse events that present new demands for imaging to guide treatment decisions. Emerging and evolving approaches to immunotherapy highlight further key issues for imaging evaluation, such as dissociated response following local administration of immune checkpoint modulators, pseudoprogression due to immune infiltration in the tumor environment, and premature death due to hyperprogression. Research that may offer tools for radiologists to meet these challenges is reviewed. Different modalities are discussed, including immuno-PET, as well as new applications of CT, MRI, and fluorodeoxyglucose PET, such as radiomics and imaging of hematopoietic tissues or anthropometric characteristics. Multilevel integration of imaging and other biomarkers may improve clinical guidance for immunotherapies and provide theranostic opportunities.

Advantages of FBPA PET in evaluating early response of anti-PD-1 immunotherapy in B16F10 melanoma-bearing mice: Comparison to FDG PET

Purpose

PET with L-4-borono-2-[18F] fluoro-phenylalanine (FBPA) was reported to be useful to differentiate malignant tumors and inflammation. Although immunotherapy with immune checkpoint inhibitors (ICIs) has been applied to cancer treatment recently, FDG PET may not be suitable to determine the effect of ICIs because of false-positive findings caused by treatment-related inflammation. In this study, we aimed to demonstrate that FBPA PET allowed detection of the early response of anti-PD-1 immunotherapy in tumor-bearing mice, comparing the results with those of FDG PET.

Materials and methods

Mice with B16F10 melanoma tumor xenografts were prepared. Anti-mouse PD-1 antibody or PBS was administered twice intraperitoneally to the tumor-bearing mice on Day 0 (3 days after inoculation) and Day 5 (treatment or control group ). PET/CT imaging was performed twice for each mouse on Day 0 before the anti-PD-1 antibody/PBS administration and on Day 7 using a micro-PET/CT scanner. FBPA and FDG PET/CT studies were conducted separately. SUVmax and the tumor to liver ratio (T/L ratio) were used as parameters exhibiting tumor activity. Tumor uptake volume (TUV) and metabolic tumor volume (MTV) were also calculated for FBPA and FDG, respectively. Changes between pre- and posttreatment SUVmax or T/L ratio were observed using the formula as follows: [(posttreatment parameter values/pretreatment values - 1) × 100] (%).

Results

Tumors in TrG were smaller than those in CoG on Day 7. SUVmax and T/L ratio represented no differences between TrG and CoG in FBPA and FDG PET before treatment. FBPA PET on Day 7 demonstrated that SUVmax, T/L ratio, and TUV in TrG were statistically smaller than those in CoG. %T/L ratio and %SUVmax exhibited the same trend in FBPA PET. However, FDG PET on Day 7 revealed no differences in all parameters between TrG and CoG. T/L ratio and %SUVmax in TrG represented larger values than those in CoG without statistical significances.

Conclusion

This study demonstrated that FBPA PET allowed detection of the early response of anti-PD-1 immunotherapy in B16F10 melanoma-bearing mice. FDG PET did not detect the response. Further studies are required to determine whether FBPA PET is useful in evaluating the treatment effect of ICIs in humans.

Durvalumab-induced thyroiditis in a patient with non-small cell lung carcinoma: a case report and review of pathogenic mechanisms

BACKGROUND

Immune checkpoint inhibitors (ICI) targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 and its ligand (PD-1/PD-L1) have become the current standard-of-care for advanced cancers. This novel therapeutic approach comes with its costs in the form of immune-related adverse events (irAE), including endocrinopathy.

CASE PRESENTATION

A 63-year-old woman was diagnosed with a non-small cell lung carcinoma of the right superior lobe, cT3N2M0. She developed thyrotoxicosis followed by hypothyroidism induced by consolidation immunotherapy with durvalumab (anti-PD-L1). Analysis of the human leukocyte antigen (HLA) region showed HLA-DR4 (susceptible) and DR13 (protective). The possible mechanisms are subsequently discussed in detail.

CONCLUSIONS

The case of a patient with thyroiditis associated with the PD-L1 inhibitor durvalumab is described, highlighting the need for proactive monitoring of thyroid hormone levels. Identifying biomarkers associated with an increased risk of ICI-induced side effects (such as HLA) is of interest for better patient selection, optimal management and improved understanding of the mechanisms involved.

Hypophysitis induced by anti-programmed cell death protein 1 immunotherapy in non-small cell lung cancer: Three case reports

BACKGROUND

Hypophysitis induced by programmed cell death 1 protein (PD-1) immune checkpoint inhibitors is rare and poorly described. We report three patients with non-small cell lung cancer who developed hypophysitis after anti-PD-1 immunotherapy.

CASE SUMMARY

Both case 1 and case 2 presented with common symptoms of fatigue, nausea, and vomiting. However, case 3 showed rare acute severe symptoms such as hoarse voice, bucking, and difficulty in breathing even when sitting. Following two cycles of immunotherapy in case 3, the above severe symptoms and pituitary gland enlargement were found on magnetic resonance imaging at the onset of hypophysitis. These symptoms were relieved after 10 d of steroid treatment. Case 3 was the first patient with these specific symptoms, which provided a new insight into the diagnosis of hypophysitis. In addition, we found that the clinical prognosis of patients with hypophysitis was related to the dose of steroid therapy. Case 3 was treated with high-dose hormone therapy and her pituitary-corticotropic axis dysfunction returned to normal after more than 6 mo of steroid treatment. Cases 1 and 2 were treated with the low-dose hormone, and dysfunction of the pituitary-corticotropic axis was still present after up to 7 mo of steroid treatment.

CONCLUSION

The clinical symptoms described in this study provide a valuable reference for the diagnosis and treatment of immune-related hypophysitis.

Emerging Biomaterials Imaging Antitumor Immune Response

Immunotherapy is one of the most promising clinical modalities for the treatment of malignant tumors and has shown excellent therapeutic outcomes in clinical settings. However, it continues to face several challenges, including long treatment cycles, high costs, immune-related adverse events, and low response rates. Thus, it is critical to predict the response rate to immunotherapy by using imaging technology in the preoperative and intraoperative. Here, the latest advances in nanosystem-based biomaterials used for predicting responses to immunotherapy via the imaging of immune cells and signaling molecules in the immune microenvironment are comprehensively summarized. Several imaging methods, such as fluorescence imaging, magnetic resonance imaging, positron emission tomography imaging, ultrasound imaging, and photoacoustic imaging, used in immune predictive imaging, are discussed to show the potential of nanosystems for distinguishing immunotherapy responders from nonresponders. Nanosystem-based biomaterials aided by various imaging technologies are expected to enable the effective prediction and diagnosis in cases of tumors, inflammation, and other public diseases.

Artificial intelligence and radiomics: fundamentals, applications, and challenges in immunotherapy

Immunotherapy offers the potential for durable clinical benefit but calls into question the association between tumor size and outcome that currently forms the basis for imaging-guided treatment. Artificial intelligence (AI) and radiomics allow for discovery of novel patterns in medical images that can increase radiology’s role in management of patients with cancer, although methodological issues in the literature limit its clinical application. Using keywords related to immunotherapy and radiomics, we performed a literature review of MEDLINE, CENTRAL, and Embase from database inception through February 2022. We removed all duplicates, non-English language reports, abstracts, reviews, editorials, perspectives, case reports, book chapters, and non-relevant studies. From the remaining articles, the following information was extracted: publication information, sample size, primary tumor site, imaging modality, primary and secondary study objectives, data collection strategy (retrospective vs prospective, single center vs multicenter), radiomic signature validation strategy, signature performance, and metrics for calculation of a Radiomics Quality Score (RQS). We identified 351 studies, of which 87 were unique reports relevant to our research question. The median (IQR) of cohort sizes was 101 (57–180). Primary stated goals for radiomics model development were prognostication (n=29, 33.3%), treatment response prediction (n=24, 27.6%), and characterization of tumor phenotype (n=14, 16.1%) or immune environment (n=13, 14.9%). Most studies were retrospective (n=75, 86.2%) and recruited patients from a single center (n=57, 65.5%). For studies with available information on model testing, most (n=54, 65.9%) used a validation set or better. Performance metrics were generally highest for radiomics signatures predicting treatment response or tumor phenotype, as opposed to immune environment and overall prognosis. Out of a possible maximum of 36 points, the median (IQR) of RQS was 12 (10–16). While a rapidly increasing number of promising results offer proof of concept that AI and radiomics could drive precision medicine approaches for a wide range of indications, standardizing the data collection as well as optimizing the methodological quality and rigor are necessary before these results can be translated into clinical practice.

Quantitative imaging biomarkers of immune-related adverse events in immune-checkpoint blockade-treated metastatic melanoma patients: a pilot study

PURPOSE

To develop quantitative molecular imaging biomarkers of immune-related adverse event (irAE) development in malignant melanoma (MM) patients receiving immune-checkpoint inhibitors (ICI) imaged with 18F-FDG PET/CT.

METHODS

18F-FDG PET/CT images of 58 MM patients treated with anti-PD-1 or anti-CTLA-4 ICI were retrospectively analyzed for indication of irAE. Three target organs, most commonly affected by irAE, were considered: bowel, lung, and thyroid. Patient charts were reviewed to identify which patients experienced irAE, irAE grade, and time to irAE diagnosis. Target organs were segmented using a convolutional neural network (CNN), and novel quantitative imaging biomarkers - SUV percentiles (SUVX%) of 18F-FDG uptake within the target organs - were correlated with the clinical irAE status. Area under the receiver-operating characteristic curve (AUROC) was used to quantify irAE detection performance. Patients who did not experience irAE were used to establish normal ranges for target organ 18F-FDG uptake.

RESULTS

A total of 31% (18/58) patients experienced irAE in the three target organs: bowel (n=6), lung (n=5), and thyroid (n=9). Optimal percentiles for identifying irAE were bowel (SUV95%, AUROC=0.79), lung (SUV95%, AUROC=0.98), and thyroid (SUV75%, AUROC=0.88). Optimal cut-offs for irAE detection were bowel (SUV95%>2.7 g/mL), lung (SUV95%>1.7 g/mL), and thyroid (SUV75%>2.1 g/mL). Normal ranges (95% confidence interval) for the SUV percentiles in patients without irAE were bowel [1.74, 2.86 g/mL], lung [0.73, 1.46 g/mL], and thyroid [0.86, 1.99 g/mL].

CONCLUSIONS

Increased 18F-FDG uptake within irAE-affected organs provides predictive information about the development of irAE in MM patients receiving ICI and represents a potential quantitative imaging biomarker for irAE. Some irAE can be detected on 18F-FDG PET/CT well before clinical symptoms appear.

Translating Molecules into Imaging—The Development of New PET Tracers for Patients with Melanoma

Melanoma is a deadly disease that often exhibits relentless progression and can have both early and late metastases. Recent advances in immunotherapy and targeted therapy have dramatically increased patient survival for patients with melanoma. Similar advances in molecular targeted PET imaging can identify molecular pathways that promote disease progression and therefore offer physiological information. Thus, they can be used to assess prognosis, tumor heterogeneity, and identify instances of treatment failure. Numerous agents tested preclinically and clinically demonstrate promising results with high tumor-to-background ratios in both primary and metastatic melanoma tumors. Here, we detail the development and testing of multiple molecular targeted PET-imaging agents, including agents for general oncological imaging and those specifically for PET imaging of melanoma. Of the numerous radiopharmaceuticals evaluated for this purpose, several have made it to clinical trials and showed promising results. Ultimately, these agents may become the standard of care for melanoma imaging if they are able to demonstrate micrometastatic disease and thus provide more accurate information for staging. Furthermore, these agents provide a more accurate way to monitor response to therapy. Patients will be able to receive treatment based on tumor uptake characteristics and may be able to be treated earlier for lesions that with traditional imaging would be subclinical, overall leading to improved outcomes for patients.

Interpretation of 2-[18F]FDG PET/CT in Hodgkin lymphoma patients treated with immune checkpoint inhibitors

The development of immunotherapy has revolutionized cancer treatment, improving the outcome and survival of many patients. Immune checkpoint inhibitors (ICIs), the most common form of immunotherapy, use antibodies to restore T-cells' anti-tumor activity. Immune checkpoint inhibitors are gaining ground in the therapeutic strategy across various cancers. Although widely used in solid tumors, ICIs have shown remarkable efficacy in patients with Hodgkin lymphoma. 2-[¹⁸F]Fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/CT is the gold standard to stage and monitor responses in Hodgkin lymphoma. This article reviewed the use of 2-[¹⁸F]FDG-PET/CT in patients with Hodgkin lymphoma treated with ICI, focusing on image interpretation for response monitoring and detecting adverse events. Key Points • Immune checkpoint inhibitors have dramatically improved the outcome of patients with cancer. Their mechanisms of action induce inflammatory processes that might translate into a high 2-[¹⁸F]FDG uptake visible on 2-[¹⁸F]FDG-PET/CT, requiring an adaptation of the evaluation criteria. • PET readers should be aware of new patterns of response observed with immunotherapy in assessing treatment response in HL patients. • -[¹⁸F]FDG-PET/CT has an unparalleled ability of assessing tumor response, visualizing signs of immune activation as well as immune-related adverse events in a one-stop-shop examination.

Teaching cancer imaging in the era of precision medicine: Looking at the big picture

The role of imaging in cancer diagnosis and treatment has evolved at the same rapid pace as cancer management. Over the last twenty years, with the advancement of technology, oncology has become a multidisciplinary field that allows for researchers and clinicians not only to create individualized treatment options for cancer patients, but also to evaluate patients’ response to therapy with increasing precision. Familiarity with these concepts is a requisite for current and future radiologists, as cancer imaging studies represent a significant and growing component of any radiology practice, from tertiary cancer centers to community hospitals.

In this review we provide the framework to teach cancer imaging in the era of genomic oncology. After reading this article, readers should be able to illustrate the basics cancer genomics, modern cancer genomics, to summarize the types of systemic oncologic therapies available, their patterns of response and their adverse events, to discuss the role of imaging in oncologic clinical trials and the role of tumor response criteria and to display the future directions of oncologic imaging.

Harnessing big data to characterize immune-related adverse events

Immune-checkpoint inhibitors (ICIs) have transformed patient care in oncology but are associated with a unique spectrum of organ-specific inflammatory toxicities known as immune-related adverse events (irAEs). Given the expanding use of ICIs, an increasing number of patients with cancer experience irAEs, including severe irAEs. Proper diagnosis and management of irAEs are important to optimize the quality of life and long-term outcomes of patients receiving ICIs; however, owing to the substantial heterogeneity within irAEs, and despite multicentre initiatives, performing clinical studies of these toxicities with a sufficient cohort size is challenging. Pioneering studies from the past few years have demonstrated that aggregate clinical data, real-world data (such as data on pharmacovigilance or from electronic health records) and multi-omics data are alternative tools well suited to investigating the underlying mechanisms and clinical presentations of irAEs. In this Perspective, we summarize the advantages and shortcomings of different sources of 'big data' for the study of irAEs and highlight progress made using such data to identify biomarkers of irAE risk, evaluate associations between irAEs and therapeutic efficacy, and characterize the effects of demographic and anthropometric factors on irAE risk. Harnessing big data will accelerate research on irAEs and provide key insights that will improve the clinical management of patients receiving ICIs.

Prognostic value of immunotherapy-induced organ inflammation assessed on 18FDG PET in patients with metastatic non-small cell lung cancer

PURPOSE

We evaluated the prognostic value of immunotherapy-induced organ inflammation observed on ¹⁸FDG PET in patients with non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICPIs).

METHODS

Data from patients with IIIB/IV NSCLC included in two different prospective trials were analyzed. ¹⁸FDG PET/CT exams were performed at baseline (PET_Baseline) and repeated after 7-8 weeks (PET_Interim1) and 12-16 weeks (PET_Interim2) of treatment, using iPERCIST for tumor response evaluation. The occurrence of abnormal organ ¹⁸FDG uptake, deemed to be due to ICPI-related organ inflammation, was collected.

RESULTS

Exploratory cohort (Nice, France): PET_Interim1 and PET_Interim2 revealed the occurrence of at least one ICPI-induced organ inflammation in 72.8% of patients, including midgut/hindgut inflammation (33.7%), gastritis (21.7%), thyroiditis (18.5%), pneumonitis (17.4%), and other organ inflammations (9.8%). iPERCIST tumor response was associated with improved progression-free survival (p < 0.001). iPERCIST tumor response and immuno-induced gastritis assessed on PET were both associated with improved overall survival (OS) (p < 0.001 and p = 0.032). Combining these two independent variables, we built a model predicting patients' 2-year OS with a sensitivity of 80.3% and a specificity of 69.2% (AUC = 72.7). Validation cohort (Genova, Italy): Immuno-induced gastritis (19.6% of patients) was associated with improved OS (p = 0.04). The model built previously predicted 2-year OS with a sensitivity and specificity of 72.0% and 63.6% (AUC = 70.7) and 3-year OS with a sensitivity and specificity of 69.2% and 80.0% (AUC = 78.2).

CONCLUSION

Immuno-induced gastritis revealed by early interim ¹⁸FDG PET in around 20% of patients with NSCLC treated with ICPI is a novel and reproducible imaging biomarker of improved OS.

Immune Checkpoint Inhibitor-Associated Colitis: From Mechanism to Management

Immune checkpoint inhibitors (ICIs), as one of the innovative types of immunotherapies, including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors, have obtained unprecedented benefit in multiple malignancies. However, the immune response activation in the body organs could arise immune-related adverse events (irAEs). Checkpoint inhibitor colitis (CIC) is the most widely reported irAEs. However, some obscure problems, such as the mechanism concerning gut microbiota, the confusing differential diagnosis with inflammatory bowel disease (IBD), the optimal steroid schedule, the reintroduction of ICIs, and the controversial prognosis features, influence the deep understanding and precise diagnosis and management of CIC. Herein, we based on these problems and comprehensively summarized the relevant studies of CIC in patients with NSCLC, further discussing the future research direction of this specific pattern of irAEs.

Response criteria for immunotherapy and the radiologic patterns of immune-related adverse events

Immunotherapy has revolutionized clinical outcomes in both early-stage and advanced-stage malignancies. Immunotherapy has improved patient survival in both solid and hematologic disorders with the potential added benefit of less toxicity compared to conventional cytotoxic chemotherapy. Imaging plays a fundamental role in monitoring treatment response and assessment of immune-related adverse events, e.g. pneumonitis, colitis, etc. Familiarity with the current strategies of immune-related response evaluation and their limitations is essential for radiologists to guide clinicians with their treatment decisions. Radiologists should be aware of the wide spectrum of immune-related adverse events and their various radiological features as well as the patterns of treatment response associated with immunotherapies.

Adverse Effects and Toxicity of Immune Checkpoint Inhibitors For Patients With Urothelial Carcinoma

Urothelial carcinoma (UC) occupies a high incidence among all the genitourinary malignancies. Immune checkpoint inhibitors (ICIs), as alternative treatments of metastatic urothelial carcinoma (mUC), have been applied in the treatment of mUC after chemotherapy failure, with comparable efficacy and safety. ICIs can enhance anti-tumor T cell reactivity and promote immune control over the cancerous cells by blocking cytotoxic T-lymphocyte antigen 4 (CTLA-4) or the combination of PD-1 and PD-L1. In the treatment of urothelial carcinoma, ICIs show obvious advantage and can enhance survival rates. However, their adverse effects are gradually manifested with increasing clinical applications. Therefore, we review the adverse effects and toxicity of ICIs in patients with UC, aiming to provide sound theoretical references and therapeutic strategies for their clinical application.

Immune-related cholangitis induced by immune checkpoint inhibitors: a systematic review of clinical features and management

BACKGROUND AIMS

Immune checkpoint inhibitors (ICIs) improve the survival of patients with advanced tumors. However, immune-related adverse events limit the use of ICIs. Although liver toxicity has been concerned gradually, little is known about bile duct injury associated with ICIs. Hence, this review aims to describe clinicopathological features, imaging, and management of immune-mediated cholangitis (IMC) induced by ICIs.

METHODS

We retrieved the literature from the PubMed database for case reports and series of IMC induced by ICIs. IMC was then classified as small-ducts type, large-ducts type and mixed type. Biochemical parameters, pathological characteristics, imaging features, treatment and response were evaluated and compared among three patterns.

RESULTS

Fifty-three cases of IMC were enrolled. The median values of alkaline phosphatase and alanine transaminase of IMC were 1328 and 156 IU/L. The ALP level of the large-ducts type was higher than that of the small-ducts type (P = 0.021). The main pathological characteristics of small-ducts cholangitis were portal inflammation, bile duct injury and ductular reaction. The imaging features of large-duct cholangitis were bile duct dilatation, stenosis and bile duct wall thickening and irregularity. Forty-eight (90%) cases received immunosuppression therapy. Biliary enzymes reduced in 79% of cases receiving immunosuppression therapy, but only 8.5% of cases returned to normal. It took a long time for biliary enzymes to recover.

CONCLUSIONS

The clinicians should be aware of the possibility of IMC if the biliary enzymes increase significantly after the use of ICIs. The liver function can be improved partially by immunosuppressive therapy in the majority of IMC.

Imaging evaluation of lung cancer treated with PD-1/PD-L1 inhibitors

Immunotherapy (PD-1/PD-L1 inhibitors) has attracted attention for lung cancer treatment and recasted the administration of immunotherapeutics to patients who have advanced/metastatic diseases. Whether in combination or as monotherapy, these medications have become common therapies for certain patients with lung cancer. Moreover, their usage is expected to expand widely in the future. This review aims to discuss the imaging evaluation of lung cancer response to PD-1/PD-L1 therapy with focus on new radiological criteria for immunotherapy response. Abnormal radiological responses (pseudoprogression, dissociative responses, and hyperprogression) and immune-related adverse events are also described.

Immune PET Imaging

Fluorodeoxyglucose (FDG) PET/CT is sensitive to metabolic, immune-related, and structural changes that can occur in tumors in cancer immunotherapy. Unique mechanisms of immune checkpoint inhibitors (ICIs) occasionally make response evaluation challenging, because tumors and inflammatory changes are both FDG avid. These response patterns and sequelae of ICI immunotherapy, such as immune-related adverse events, are discussed. Immune-specific PET imaging probes at preclinical stage or in early clinical trials, which may help guide clinical management of cancer patients treated with immunotherapy and likely have applications outside of oncology for other diseases in which the immune system plays a role, are reviewed.

Immune checkpoint inhibitor related adverse effects and FDG PET/CT findings

Immune check-point inhibitor (ICI) treatments activate the T-cells against tumor. Activated T-cells not only attack the tumor but also healthy cells, causing an autoimmune reaction in various tissues. These immune related adverse effects (IRAE) cause ¹⁸F-fluorodeoxyglucose (FDG) uptake in various tissues due to inflammation. It is important to recognize and report these findings on FDG Positron Emission Tomography/Computed Tomography (PET/CT) studies. FDG PET helps to determine the presence, location and severity of IRAEs. In severe cases, ICI treatments are interrupted or suspended and anti-inflammatory treatments are started. FDG uptake due IRAEs may mimic metastases or disease progression. Their presence may also help predicting response to treatment and have prognostic implications. In this review article, we will provide basic information about ICI treatments, IRAEs and FDG PET/CT findings.

An atypical sarcoid-like reaction during anti-protein death 1 treatment in a patient with metastatic melanoma

We report a case of anti-protein death 1-induced sarcoid-like reaction in a 63-year-old Caucasian male who was diagnosed with stage IV-M1a melanoma. He was initially treated with pembrolizumab monotherapy (Q3W) and had a complete response after 14 cycles. However, relapse was suspected 3 months later with appearance of hilar, mediastinal and hepatic hilar lymph nodes as well as a skin lesion. Biopsy of both the hilar lymph nodes and the skin lesion demonstrated sarcomatoid granulomatosis. Pembrolizumab was discontinued temporarily. While on F-FDG-PET/CT, all sarcoid-like lesions regressed in size and activity, a new hypermetabolic solitary skeletal lesion was detected in a lumbar vertebra, suspicious for metastasis. However, since the patient was asymptomatic, a watchful-waiting attitude was taken. During this period, a spontaneous and complete resolution of the metabolic activity was observed of the skeletal lesion. Until today, the patient remains in complete remission. Current case presents an atypical presentation and evolution of anti-PD-1-induced sarcoid-like reaction, illustrating the difficulty of differentiating it from disease progression. Before considering (re-)initiation of anti-melanoma therapy, a tissue biopsy of one of the suspected lesions may be performed to confirm diagnosis. Physicians treating patients with ICI should be aware of this difficulty and critically assess the nature of lesions suspect of progression in patients responding to ICI and presenting with a sarcoid-like reaction.

Current and Future Role of Medical Imaging in Guiding the Management of Patients With Relapsed and Refractory Non-Hodgkin Lymphoma Treated With CAR T-Cell Therapy

Chimeric antigen receptor (CAR) T-cells are a novel immunotherapy available for patients with refractory/relapsed non-Hodgkin lymphoma. In this indication, clinical trials have demonstrated that CAR T-cells achieve high rates of response, complete response, and long-term response (up to 80%, 60%, and 40%, respectively). Nonetheless, the majority of patients ultimately relapsed. This review provides an overview about the current and future role of medical imaging in guiding the management of non-Hodgkin lymphoma patients treated with CAR T-cells. It discusses the value of predictive and prognostic biomarkers to better stratify the risk of relapse, and provide a patient-tailored therapeutic strategy. At baseline, high tumor volume (assessed on CT-scan or on [18F]-FDG PET/CT) is a prognostic factor associated with treatment failure. Response assessment has not been studied extensively yet. Available data suggests that current response assessment developed on CT-scan or on [18F]-FDG PET/CT for cytotoxic systemic therapies remains relevant to estimate lymphoma response to CAR T-cell therapy. Nonetheless, atypical patterns of response and progression have been observed and should be further analyzed. The potential advantages as well as limitations of artificial intelligence and radiomics as tools providing high throughput quantitative imaging features is described.

Immunotherapy-Related Imaging Findings in Patients with Gynecological Malignancies: What Radiologists Need to Know

Immunotherapy is an effective treatment option for gynecological malignancies. Radiologists dealing with gynecological patients undergoing treatment with immune checkpoint inhibitors should be aware of unconventional immune-related imaging features for the evaluation of tumor response and immune-related adverse events. In this paper, immune checkpoint inhibitors used for gynecological malignancies and their mechanisms of action are briefly presented. In the second part, patterns of pseudoprogression are illustrated, and different forms of immune-related adverse events are discussed.

Biomarkers or factors for predicting the efficacy and adverse effects of immune checkpoint inhibitors in lung cancer: achievements and prospective

Immune checkpoint inhibitors (ICIs) are widely used in lung cancer therapy due to their effectiveness and minimal side effects. However, only a few lung cancer patients benefit from ICI therapy, driving the need to develop alternative biomarkers. Programmed death-ligand 1 (PD-L1) molecules expressed in tumor cells and immune cells play a key role in the immune checkpoint pathway. Therefore, PD-L1 expression is a prognostic biomarker in evaluating the effectiveness of programmed death-1 (PD-1)/PD-L1 inhibitors. Nevertheless, adverse predictive outcomes suggest that other factors are implicated in the response. In this review, we present a detailed introduction of existing biomarkers concerning tumor abnormality and host immunity. PD-L1 expression, tumor mutation burden, neoantigens, specific gene mutations, circulating tumor DNA, human leukocyte antigen class I, tumor microenvironment, peripheral inflammatory cells, and microbiome are discussed in detail. To sum up, this review provides information on the current application and future prospects of ICI biomarkers.

Imaging of T-cell Responses in the Context of Cancer Immunotherapy

Immunotherapy, which promotes the induction of cytotoxic T lymphocytes and enhances their infiltration into and function within tumors, is a rapidly expanding and evolving approach to treating cancer. However, many of the critical denominators for inducing effective anticancer immune responses remain unknown. Efforts are underway to develop comprehensive ex vivo assessments of the immune landscape of patients prior to and during response to immunotherapy. An important complementary approach to these efforts involves the development of noninvasive imaging approaches to detect immune targets, assess delivery of immune-based therapeutics, and evaluate responses to immunotherapy. Herein, we review the merits and limitations of various noninvasive imaging modalities (MRI, PET, and single-photon emission tomography) and discuss candidate targets for cellular and molecular imaging for visualization of T-cell responses at various stages along the cancer-immunity cycle in the context of immunotherapy. We also discuss the potential use of these imaging strategies in monitoring treatment responses and predicting prognosis for patients treated with immunotherapy.

Abdominal immune-related adverse events: detection on ultrasonography, CT, MRI and 18F-Fluorodeoxyglucose positron emission tomography

Immune checkpoint inhibitor and chimeric antigen receptor T-cell therapies are associated with a unique spectrum of complications termed immune-related adverse events (irAEs). The abdomen is the most frequent site of severe irAEs that require hospitalization with life-threatening consequences. Most abdominal irAEs such as enterocolitis, hepatitis, cholangiopathy, cholecystitis, pancreatitis, adrenalitis, and sarcoid-like reaction are initially detected on imaging such as ultrasonography (US), CT, MRI and fusion 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT during routine surveillance of cancer therapy. Early recognition and diagnosis of irAEs and immediate management with cessation of immune modulator cancer therapy and institution of immunosuppressive therapy are necessary to avert morbidity and mortality. Diagnosis of irAEs is confirmed by tissue sampling or by follow-up imaging demonstrating resolution. Abdominal radiologists reviewing imaging on patients being treated with anti-cancer immunomodulators should be familiar with the imaging manifestations of irAEs.

Next Generation Imaging Techniques to Define Immune Topographies in Solid Tumors

In recent years, cancer immunotherapy experienced remarkable developments and it is nowadays considered a promising therapeutic frontier against many types of cancer, especially hematological malignancies. However, in most types of solid tumors, immunotherapy efficacy is modest, partly because of the limited accessibility of lymphocytes to the tumor core. This immune exclusion is mediated by a variety of physical, functional and dynamic barriers, which play a role in shaping the immune infiltrate in the tumor microenvironment. At present there is no unified and integrated understanding about the role played by different postulated models of immune exclusion in human solid tumors. Systematically mapping immune landscapes or "topographies" in cancers of different histology is of pivotal importance to characterize spatial and temporal distribution of lymphocytes in the tumor microenvironment, providing insights into mechanisms of immune exclusion. Spatially mapping immune cells also provides quantitative information, which could be informative in clinical settings, for example for the discovery of new biomarkers that could guide the design of patient-specific immunotherapies. In this review, we aim to summarize current standard and next generation approaches to define Cancer Immune Topographies based on published studies and propose future perspectives.

Assessing immune organs on 18F-FDG PET/CT imaging for therapy monitoring of immune checkpoint inhibitors: inter-observer variability, prognostic value and evolution during the treatment course of melanoma patients

BACKGROUND

Immune checkpoint inhibitors (ICIs) have significantly improved survival in advanced melanoma. There is a need for robust biomarkers to identify patients who do not respond. We analysed 14 baseline ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) metrics and their evolution to assess their correlation with patient outcome, compared with 7 established biological markers and 7 clinical variables.

METHODS

We conducted a retrospective monocentric observational study of 29 patients with advanced melanoma who underwent baseline ¹⁸F-FDG PET/CT, followed by an early monitoring PET/CT (iPET) scan after 1 month of treatment and follow-up studies at 3rd (M3PET) and 6th month (M6PET). ¹⁸F-FDG uptake in immune organs (spleen, bone marrow, ileocecal valve) and derived spleen-to-liver (SLR) and bone-to-liver (BLR) ratios were reviewed by two PET readers for reproducibility analysis purposes including 14 PET variables. The most reproducible indexes were used for evaluation as predictors of overall survival (OS) in comparison with PET response using imPERCIST5, whole-body metabolic active tumour volume (WB-MATV) and biological parameters (lactate dehydrogenases (LDH), reactive protein c (CRP), white blood count (WBC), absolute lymphocyte count (ALC), neutrophil to lymphocyte ratio (NLR) and derived neutrophils to lymphocyte ratio).

RESULTS

Strong reproducibility's (intraclass coefficients of correlation (ICC) > 0.90) were observed for spleen anterior SUV_peak, spleen MV, spleen TLG, spleen length and BLR_mean. ICC for SLR_mean and ileocecal SUV_mean were 0.86 and 0.65, respectively. In the 1-year OS 1 group, SLR_mean tended to increase at each time point to reach a significant difference at M6-PET (p = 0.019). The same trends were observed with spleen SUV_peak anterior and spleen length. In the 1-year OS 0 group, a significative increase of spleen length was found at iPET, as compared with baseline PET (p = 0.014) and M3-PET (p = 0.0239). Univariable Kaplan-Meier survival analysis found that i%var spleen length, M3%var SLR_mean, baseline LDH, i%var NLR and response at M6PET were all predictors of 1-year OS.

CONCLUSIONS

SLR_mean is recommended as a prognosticator in melanoma patients under immunotherapy: its increase greater than 25% at 3 months, compared with baseline, was associated with poor outcome after ICIs.

Gastrointestinal adverse events of immunotherapy

Cancer immunotherapy with immune-checkpoint inhibitors (ICIs) has emerged as an effective treatment for different types of cancer. ICIs are monoclonal antibodies that inhibit the signaling pathway that suppress antitumor T-cell activity. Patients benefit from increased overall and progression-free survival, but the enhancement of normal immunity can result in autoimmune manifestations, called immune-related adverse events (IRAEs), which may lead to a discontinuation of cancer therapy and to severe also life-threating events. IRAEs may affect any organs or system in the human body, being the gastrointestinal (GI) tract one of the most involved districts. Imaging plays an important role in recognizing GI IRAEs and radiologist should be familiar with the main spectrum of radiological appearance. Indeed, early detection of GI IRAEs is crucial for proper patient management and reduces morbidity and mortality. The purpose of this review is to present the most relevant imaging manifestation of GI IRAEs.

Impact of PET/CT for Assessing Response to Immunotherapy-A Clinical Perspective

Cancer immunotherapy using immune-checkpoint inhibitors (ICI) has revolutionized the therapeutic landscape of various malignancies like non-small-cell lung cancer or melanoma. Pre-therapy response prediction and assessment during ICI treatment is challenging due to the lack of reliable biomarkers and the possibility of atypical radiological response patterns. Positron emission tomography/computed tomography (PET/CT) enables the visualization and quantification of metabolic lesion activity additional to conventional CT imaging. Various biomarkers derived from PET/CT have been reported as predictors for response to ICI and may aid to overcome the challenges clinicians currently face in the management of ICI-treated patients. In this narrative review, experts in nuclear medicine, thoracic oncology, dermatooncology, hemato- and internal oncology, urological and head/neck tumors performed literature reviews in their respective field and a joint discussion on the use of PET/CT in the context of ICI treatment. The aims were to give a clinical overview on present standards and evidence, to identify current challenges and fields of research and to enable an outlook to future developments and their possible implications. Multiple promising studies concerning ICI response assessment or prediction using biomarkers derived from PET/CT alone or as composite biomarkers have been identified for various malignancies and disease stages. Of interest, additional major incentives in the field may evolve from novel tracers specifically targeting immune-checkpoint molecules which could allow not only response assessment and prognosis, but also visualization of histological tumor cell properties like programmed death-ligand (PD-L1) expression in vivo. Despite the broad range of existing literature on PET/CT-derived biomarkers in ICI therapy, implications for daily clinical practice remain elusive. High-quality prospective data are urgently warranted to determine whether patients benefit from the application of PET/CT in terms of prognosis. At the moment, the lack of such evidence as well as the absence of standardized imaging methods and biomarkers still precludes PET/CT imaging to be included in the relevant clinical practice guidelines.

Application and Prospects of Molecular Imaging in Immunotherapy

Recently, immunotherapies that target the interactions of programmed cell death 1 (PD-1) with its major ligands, programmed death ligand 1 (PD-L1) and programmed death ligand 2 (PD-L2), have achieved significant success. To date, several immune checkpoint inhibitors targeting the PD-1/PD-L1 pathway have been developed to treat melanoma, non-small cell lung cancer, head and neck cancer, renal cell carcinoma, and urothelial carcinoma. Despite promising outcomes with immunotherapy, there are many limitations to several current immune biomarkers for predicting immune benefits and to traditional imaging for evaluating the efficacy and prognosis of immunotherapy and monitoring adverse reactions. In this review, we recommend a novel imaging method, molecular imaging. This paper reviews the application and prospects of molecular imaging in the context of current immunotherapies in regard to the following aspects: 1) detecting the expression of PD-1/PD-L1; 2) evaluating the efficacy of immunotherapy; 3) assessing patient prognosis with immunotherapy; 4) monitoring the toxicity of immunotherapy; and 5) other targets imaging.

The Role of 18F-FDG PET/CT in Guiding Precision Medicine for Invasive Bladder Carcinoma

Bladder cancer (BC) is the 10th most common cancer worldwide. Approximately one quarter of patients with BC have muscle-invasive disease (MIBC). Muscle-invasive disease carries a poor prognosis and choosing the optimal treatment option is critical to improve patients’ outcomes. Ongoing research supports the role of 2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography (18F-FDG PET) in guiding patient-specific management decisions throughout the course of MIBC. As an imaging modality, 18F-FDG PET is acquired simultaneously with either computed tomography (CT) or MRI to offer a hybrid approach combining anatomical and metabolic information that complement each other. At initial staging, 18F-FDG PET/CT enhances the detection of extravesical disease, particularly in patients classified as oligometastatic by conventional imaging. 18F-FDG PET/CT has value in monitoring response to neoadjuvant and systemic chemotherapy, as well as in localizing relapse after treatment. In the new era of immunotherapy, 18F-FDG PET/CT may also be useful to monitor treatment efficacy as well as to detect immune-related adverse events. With the advent of artificial intelligence techniques such as radiomics and deep learning, these hybrid medical images can be mined for quantitative data, providing incremental value over current standard-of-care clinical and biological data. This approach has the potential to produce a major paradigm shift toward data-driven precision medicine with the ultimate goal of personalized medicine. In this review, we highlight current literature reporting the role of 18F-FDG PET in supporting personalized management decisions for patients with MIBC. Specific topics reviewed include the incremental value of 18F-FDG PET in prognostication, pre-operative planning, response assessment, prediction of recurrence, and diagnosing drug toxicity.

Immune checkpoint inhibitor-associated pituitary adverse events: an observational, retrospective, disproportionality study

PURPOSE

The aim of this study was to identify and characterize immune checkpoint inhibitors (ICIs)-associated pituitary adverse events (AEs).

METHODS

This is a retrospective disproportionality study based on VigiBase, the World Health Organization (WHO) global database of individual case safety reports (ICSRs), with a study period from January 1, 2011 to March 6, 2019. Information component (IC) and reporting odds ratio (ROR) are measures of disproportionate analysis. IC was used to evaluate the association between ICIs and pituitary AEs, while ROR was used to evaluate the differences in reporting of pituitary AEs between different ICI subgroups.

RESULTS

The following ICI-associated pituitary diseases have been increasingly reported: hypophysitis (835 reports; information component 6.74 [95% CI 6.63-6.83]), hypopituitarism (268; 6.12 [95% CI 5.92-6.27]), pituitary enlargement (28; 5.19 [95% CI 4.57-5.63]). The anti-CTLA-4 subgroup had a stronger association with hypophysitis/hypopituitarism than the anti-PD (anti-PD-1 or anti-PD-L1) subgroup (ROR 8.0 [95% CI 6.7-9.6]). Among ICI-associated hypophysitis/hypopituitarism cases, the proportion of male was higher than female (630 [63.9%] vs 356 [36.1%]). Anti-CTLA-4 subgroup and ICI combination (nivolumab plus ipilimumab) subgroup both had a significantly earlier onset time than anti-PD subgroup (67 days [IQR 48-87]; 90 [IQR 34-155]; 140 [IQR 62-218], both p < 0.05). Other endocrinopathies that co-occurred with hypophysitis/hypopituitarism were adrenal insufficiency, thyroid dysfunction, diabetes mellitus and diabetes insipidus. Gastrointestinal disorder was the most common concurrent disease except for endocrinopathies.

CONCLUSIONS

ICI-associated pituitary adverse events have significantly increased, and their clinical characteristics should be kept in mind by oncologists and endocrinologists who manage patients treated by immunotherapy.

Thyroid Toxicity Following Immune Checkpoint Inhibitor Treatment in Advanced Cancer

Background: Inhibitory antibodies against cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death-1 (PD-1) have antitumor efficacy and are now standard of care in the management of multiple cancer subtypes. However, the use is complicated by the development of autoimmunity, which can occur in multiple organ systems. Thyroiditis is the most common immune-related adverse event. Summary: Immune checkpoint inhibitor (ICI)-associated thyroiditis affects over 10% of treated patients. PD-1 inhibitors are associated with greater risk of thyroid dysfunction relative to CTLA-4 inhibitors, although the highest risk occurs with combined anti-CTLA-4 and anti-PD-1 treatment. Onset is typically rapid, within weeks to months and both hyperthyroidism and hypothyroidism can occur. The most frequent pattern of thyroid dysfunction is transient hyperthyroidism with evolution to hypothyroidism over four to six weeks. Most cases are asymptomatic and resolve without dedicated treatment. There is no sex or age predominance, and predictive risk factors have not been reliably identified. Thyroid autoantibodies are variably present and are not clearly related to the risk or progression of thyroid dysfunction following treatment with an ICI. Observational data suggest that development of ICI-associated thyroiditis may predict improved survival. Conclusions: ICI-associated thyroiditis is a distinct clinical entity. Mechanisms underlying etiology remain largely unknown. Awareness among health professionals is important to limit morbidity and avoid unnecessary periods of untreated hypothyroidism.

Imaging and clinical manifestations of immune checkpoint inhibitor-related colitis in cancer patients treated with monotherapy or combination therapy

PURPOSE

To determine the frequency, imaging, and clinical manifestations of immune checkpoint inhibitor (ICI)-related colitis in cancer patients on monotherapy or combination therapy.

METHODS

The electronic medical records of 1044 cancer patients who received ICIs were retrospectively reviewed to identify 48 patients who had a clinical diagnosis of immune-related colitis. Imaging studies were reviewed to identify patients with imaging manifestations of colitis. Demographic data, type of ICIs, symptoms, presence of other immune-related adverse events (irAEs), and management were recorded.

RESULTS

There was imaging evidence of immune-related colitis in 34 patients (24 men; median age: 63.5 years). The median time to onset of colitis was 75 days (IQR 25-75, 49.5-216 days) in patients receiving monotherapy (group 1) and 78 days (IQR 25-75, 44.3-99.5 days) in patients undergoing combination therapy (group 2) following start of ICI. Symptoms included diarrhea (91.1% [31 of 34]), nausea/vomiting (52.9% [18 of 34]), and abdominal pain (52.9% [18 of 34]). The most common imaging findings were bowel wall thickening (97% [33 of 34]) and fluid-filled colon (82.3% [28 of 34]). Colitis was diffuse in 21 of 34 (61.8%) patients. Imaging manifestations did not differ between the two groups (p > 0.05). Steroids and antibiotics were used to treat colitis in 29 of 34 (85.2%) and 13 of 34 (38.2%) patients, respectively. No patients in group 1 experienced concurrent irAEs, but 5 of 18 (27.8%) of patients in group 2 had other irAEs (p = 0.046).

CONCLUSION

Immune-related colitis occurred in 3.3% of patients receiving ICIs with bowel wall thickening, fluid-filled colon and pancolitis being the most common imaging manifestations. Imaging manifestations did not differ between patients receiving monotherapy or combination therapy. However, concurrent irAEs were significantly observed in patients undergoing combination therapy.