Imaging Findings in Patients with Immune Checkpoint Inhibitor-Induced Arthritis

Musculoskeletal ultrasound characteristics of checkpoint inhibitor-associated inflammatory arthritis

BACKGROUND

Cancer immunotherapy with checkpoint inhibition (ICI) has revolutionized the treatment of solid cancers; however, it is associated with a spectrum of immune-related adverse events (irAEs), including inflammatory arthritis. Here we report our experience with the use of point-of-care musculoskeletal ultrasound (MSKUS) and provide a description of MSKUS findings in patients with definite musculoskeletal irAEs.

METHODS

Patients ≥18 years who received ICI at the Mass General Cancer Center from 2010-2019 were referred to rheumatology by oncology for evaluation of musculoskeletal symptoms following ICI therapy. Fifty-five patients with suspected MSK irAEs had MSKUS performed and interpreted by the same ultrasonographer. Findings were reviewed and confirmed by a blinded US reader. US findings in patients with definite de novo MSK irAEs were reviewed and correlated with the presence or absence of documented clinical synovitis and with available synovial fluid analysis.

RESULTS

Thirty-four out of fifty-five patients (62 %) had definite de novo irAE. Seven patients were identified with alternative etiologies assisted by diagnostic MSKUS. Twenty patients with definite de novo irAE had clinical evidence of synovitis at the time of the initial MSKUS examination, while 14 did not. Among patients with clinically evident synovitis, MSKUS examination confirmed inflammatory pathology in all patients. The most common MSKUS features identified were grade 2 or higher synovial thickening (80 %), hyperemia measured by color power Doppler (CPD) signal (70 %), and tenosynovitis (60 %). Among the 14 patients without clinically evident synovitis, inflammatory features were identified in 10 patients (71 %); the most common features identified were > grade 1 synovial proliferation, hyperemia and tenosynovitis. Of 15 patients who underwent synovial fluid analysis, 7 patients had synovial fluid cell counts < 2000 cells/µL considered traditionally within the 'non-inflammatory' range, and all 7 patients were noted to have inflammatory MSKUS findings.

CONCLUSION

Point-of-care MSKUS is a valuable tool in the evaluation of potential MSK irAEs. Our data demonstrates its ability to expediate early identification of subclinical synovitis and/or tenosynovitis even when synovial fluid analysis is within the traditional non-inflammatory range.

Severe Polymyalgia Rheumatica-Like Syndrome Induced by Immune Checkpoint Inhibitor: A Case Report and Literature Review

Immune checkpoint inhibitors (ICIs) have dramatically improved the prognosis of patients with cancers. However, ICIs can provoke systemic toxicities, which are known as immune-related adverse events (irAEs). Polymyalgia rheumatica (PMR)-like syndrome induced by ICI is one of the most common rheumatic irAEs. However, the management of PMR-like syndrome has not been established yet, and the optimal dose of corticosteroids remains unknown, especially for severe cases. A man in his 60s with advanced esophageal squamous cell carcinoma receiving nivolumab and ipilimumab therapy presented with a fever. Subsequently, the patient experienced bilateral femoral pain and progressive fatigue and was unable to stand within a week. The diagnosis of polymyalgia rheumatica (PMR)-like syndrome was made, and high-dose glucocorticoid therapy was started. The symptoms subsided the next day, and the corticosteroids could be quickly tapered into 10 mg over 3 weeks. The patient had sustained disease control 1 year after ICIs were discontinued. High-dose glucocorticoid therapy achieved prompt improvement of symptoms of PMR-like syndrome, even in a severe case, without compromising the anti-tumor effect of ICIs. However, the ideal treatment approach remains unknown, and prospective clinical studies are needed to determine the best strategy, especially in severe cases.

Immune-Related Adverse Events Induced by Immune Checkpoint Inhibitors and CAR-T Cell Therapy: A Comprehensive Imaging-Based Review

Immunotherapy has revolutionized oncology care, improving patient outcomes in several cancers. However, these therapies are also associated with typical immune-related adverse events due to the enhanced inflammatory and immune response. These toxicities can arise at any time during treatment but are more frequent within the first few months. Any organ and tissue can be affected, ranging from mild to life-threatening. While some manifestations are common and more often mild, such as dermatitis and colitis, others are rarer and more severe, such as myocarditis. Management depends on the severity, with treatment being held for >grade 2 toxicities. Steroids are used in more severe cases, and immunosuppressive treatment may be considered for non-responsive toxicities, along with specific organ support. A multidisciplinary approach is mandatory for prompt identification and management. The diagnosis is primarily of exclusion. It often relies on imaging features, and, when possible, cytologic and/or pathological analyses are performed for confirmation. In case of clinical suspicion, imaging is required to assess the presence, extent, and features of abnormalities and to evoke and rule out differential diagnoses. This imaging-based review illustrates the diverse system-specific toxicities associated with immune checkpoint inhibitors and chimeric antigen receptor T-cells with a multidisciplinary perspective. Clinical characteristics, imaging features, cytological and histological patterns, as well as the management approach, are presented with insights into radiological tips to distinguish these toxicities from the most important differential diagnoses and mimickers-including tumor progression, pseudoprogression, inflammation, and infection-to guide imaging and clinical specialists in the pathway of diagnosing immune-related adverse events.

Polymyalgia rheumatica and giant cell arteritis induced by immune checkpoint inhibitors: A systematic literature review highlighting differences from the idiopathic forms

INTRODUCTION

An altered immune tolerance disturbed by immune checkpoint inhibitors (ICIs) may contribute to new-onset polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). This systematic literature review (SLR) examines the characteristics of PMR and GCA-like syndromes following anticancer treatment with ICIs, summarizing their demographic, clinical and treatment-related features to provide insights whether they differ from the idiopathic forms.

METHODS

The SLR was conducted in Medline and EMBASE databases from inception to July 2024, and in the EULAR/ACR abstract database (2021-2023). ICI-induced PMR and GCA syndromes were compared to the primary forms of the diseases using data from studies that included both groups as comparators. For manuscripts lacking direct comparisons, we summarized the main findings and discussed the differences using systematic reviews or large observational studies on the primary forms.

RESULTS

From 1237 screened abstracts, 46 met the inclusion criteria, involving 358 patients (314 with ICI-PMR and 44 with ICI-GCA). ICI-PMR had an estimated pooled prevalence of 0.1% [95% CI: 0.07%, 0.14%] among ICI recipients and 15.9% [95% CI: 12.6%, 19.9%] among patients experiencing rheumatic immune-related adverse events. Patients with ICI-PMR had a male-to-female ratio of 1.7:1 and a mean age of 71 ± 4 years. Most cases were associated with PD1/PDL1 blockers (87%). Clinical features included inflammatory pain in the girdles (100%), though pelvic girdle involvement was under-reported in some cases (3/28 studies). Peripheral arthritis was present in 35% of patients. Laboratory tests showed normal or slightly elevated inflammatory markers in 26% of cases. Glucocorticoids (GCs) led to symptom improvement in 84% of cases although 20% required immunosuppressive treatment and 14% experienced relapses. ICI-GCA had a prevalence of 0.06% among ICI recipients, with equal gender distribution and a mean age of 71 ± 5 years. Most patients received anti-PD1/PDL1 blockers (57%). Clinical manifestations included cephalic symptoms (75%), permanent visual loss (23%) and symptoms related to large-vessel involvement (54%). High-dose GCs were effective, with 96% achieving remission, though 17% experienced relapses.

CONCLUSIONS

ICI-induced PMR and GCA may have distinct clinical profiles compared to idiopathic forms, with potentially milder symptoms and better treatment responses. Further studies are needed to confirm these findings and better understand the long-term outcomes and pathophysiology of these conditions.

Is 18F-FDG-PET/CT an Optimal Imaging Modality for Detecting Immune-Related Adverse Events after Immune-Checkpoint Inhibitor Therapy? Pros and Cons

Immunotherapy with immune checkpoint inhibitors (ICIs) has revolutionized contemporary oncology, presenting efficacy in various solid tumors and lymphomas. However, ICIs may potentially overstimulate the immune system, leading to immune-related adverse events (irAEs). IrAEs may affect multiple organs, such as the colon, stomach, small intestine, kidneys, skin, lungs, joints, liver, lymph nodes, bone marrow, brain, heart, and endocrine glands (e.g., pancreas, thyroid, or adrenal glands), exhibiting autoimmune inflammation. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is commonly used in oncology for staging and assessment of therapy responses, but it may also serve as a tool for detecting irAEs. This review aims to present various patterns of metabolic activation associated with irAEs due to ICI treatment, identifiable through 18F-FDG PET/CT. It describes the advantages of early detection of irAEs, but also presents the challenges in differentiating them from tumor progression. It also delves into aspects of molecular response assessment within the context of pseudoprogression and hyperprogression, along with typical imaging findings related to these phenomena. Lastly, it summarizes the role of functional PET imaging in oncological immunotherapy, speculating on its future significance and limitations.

Immune Checkpoint Inhibitor-induced Inflammatory Arthritis: Current Approaches to Management

The introduction of immune checkpoint inhibitors (ICIs) has changed the landscape of the treatment of cancer. Several immune-related adverse events (irAEs) have now been described such as ICI-inflammatory arthritis (IA), sicca syndrome, polymyalgia rheumatica, myositis, and vasculitis as a consequence of immune activation. The onset of the ICI-IA can vary from after the first infusion of ICIs to a delayed presentation a year or more after ICI initiation. Ultimately, baseline patient and tumor characteristics, the types of immunotherapies used, pre-existing autoimmune diseases, and/or other irAEs, as well as patient preferences will all shape the discussions around ICI-IA management.

Imaging in Rheumatic Immune-related Adverse Events

Since their introduction, immune checkpoint inhibitors have revolutionized cancer treatment by harnessing the body's own immune system as a defense against tumor growth. The downside of activating the immune system is the development of immune-related adverse events (irAEs), which mimic autoimmune disease of various organ systems. The musculoskeletal system is an uncommon, but substantial one for patients and can lead to long-term pain and disability that affects their quality of life. This review summarizes recent literature on imaging forms utilized for diagnosis and assessing treatment response in rheumatic irAEs.

Decoding polymyalgia rheumatica, the role of Nuclear Medicine Imaging

Polymyalgia rheumatica (PMR) is an inflammatory joint disease that presents in patients older than 50 years with prolonged morning pain and stiffness in the shoulder and hip joints and neck. The lack of specific clinical findings, laboratory signs, biomarkers and established imaging methods makes it difficult to diagnose patients with this disease. 18F-FDG PET/CT is a functional imaging technique that is an established tool in oncology and has also proven useful in the field of inflammatory diseases. The aim of this paper is to present literature evidence on the use of molecular imaging methods such as PET/CT for early diagnosis, assessment of disease activity and therapeutic response in PMR. At the same time, the advantages, disadvantages and contraindications of other methods are considered.

Calprotectin in Patients with Rheumatic Immunomediated Adverse Effects Induced by Checkpoints Inhibitors

BACKGROUND

this is an exploratory study to evaluate calprotectin serum levels in patients with rheumatic immune-related adverse events (irAEs) induced by immune checkpoint inhibitor (ICI) treatment.

METHODS

this is a retrospective observational study including patients with irAEs rheumatic syndromes. We compared the calprotectin levels to those in a control group of patients with RA and with a control group of healthy individuals. Additionally, we included a control group of patients treated with ICI but without irAEs to check calprotectin levels. We also analysed the performance of calprotectin for the identification of active rheumatic disease using receiver operating characteristic curves (ROC).

RESULTS

18 patients with rheumatic irAEs were compared to a control group of 128 RA patients and another group of 29 healthy donors. The mean calprotectin level in the irAE group was 5.15 μg/mL, which was higher than the levels in both the RA group (3.19 μg/mL) and the healthy group (3.81 μg/mL) (cut-off 2 μg/mL). Additionally, 8 oncology patients without irAEs were included. In this group, calprotectin levels were similar to those of the healthy controls. In patients with active inflammation, the calprotectin levels in the irAE group were significantly higher (8.43 μg/mL) compared to the RA group (3.94 μg/mL). ROC curve analysis showed that calprotectin had a very good discriminatory capacity to identify inflammatory activity in patients with rheumatic irAEs (AUC of 0.864).

CONCLUSIONS

the results suggest that calprotectin may serve as a marker of inflammatory activity in patients with rheumatic irAEs induced by treatment with ICIs.

Rheumatic Immune-Related Adverse Events due to Immune Checkpoint Inhibitors—A 2023 Update

With the aging of the population, malignancies are becoming common complications in patients with rheumatoid arthritis (RA), particularly in elderly patients. Such malignancies often interfere with RA treatment. Among several therapeutic agents, immune checkpoint inhibitors (ICIs) which antagonize immunological brakes on T lymphocytes have emerged as a promising treatment option for a variety of malignancies. In parallel, evidence has accumulated that ICIs are associated with numerous immune-related adverse events (irAEs), such as hypophysitis, myocarditis, pneumonitis, and colitis. Moreover, ICIs not only exacerbate pre-existing autoimmune diseases, but also cause de novo rheumatic disease–like symptoms, such as arthritis, myositis, and vasculitis, which are currently termed rheumatic irAEs. Rheumatic irAEs differ from classical rheumatic diseases in multiple aspects, and treatment should be individualized based on the severity. Close collaboration with oncologists is critical for preventing irreversible organ damage. This review summarizes the current evidence regarding the mechanisms and management of rheumatic irAEs with focus on arthritis, myositis, and vasculitis. Based on these findings, potential therapeutic strategies against rheumatic irAEs are discussed.

18F-FDG PET molecular imaging: A relevant tool to investigate chronic inflammatory rheumatisms in clinical practice?

18F-Labeled Fluorodeoxyglucose-Positron Emission Tomography (18F-FDG PET) is a molecular imaging tool commonly used in practice for the assessment of many cancers. Thanks to its properties, its use has been progressively extended to numerous inflammatory conditions, including chronic inflammatory rheumatism (CIR) such as rheumatoid arthritis (RA), spondylarthritis (SpAs) and polymyalgia rheumatica (PMR). 18F-FDG PET is currently not recommended for the diagnostic of CIRs. However, this whole-body imaging tool has emerged in clinical practice, providing a general overview of systemic involvement occurring in CIRs. Numerous studies have highlighted the capacity of 18F-FDG PET to detect articular and extra articular involvements in RA and PMR. However, the lack of specificity of 18F-FDG limits its use for diagnosis purpose. Finally, the key question is the definition of the best way to integrate this whole-body imaging tool in the patient's management workflow.