Imaging findings of immune checkpoint inhibitor associated pancreatitis

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.

Clinical characteristics and prognosis of pancreatitis associated with immune checkpoint inhibitors

BACKGROUND AND OBJECTIVE

Immune checkpoint inhibitors (ICIs) have shown remarkable efficacy against various cancers in clinical practice. However, ICIs can cause immune checkpoint inhibitor-associated pancreatic injury, often leading to drug withdrawal, and then patients must go to specialized treatment. The patients, their primary tumors are sensitive to ICIs therapy, may experience treatment delays due to such adverse reactions. Therefore, there is a need for systematic clinical researches on immune-related pancreatic toxicity to provide a clinical basis for its prevention and treatment.

METHODS

This study involved the collection of data from patients treated with ICIs and addressed pancreatic injury with preemptive treatment before continuing ICIs therapy. Then, we also statistically analyzed the incidence of pancreatic injury in patients with different courses and combined treatment, and the success rate of rechallenge treatment.

RESULTS

The study included 62 patients, with 33.9% (21/62) experiencing varying degrees of pancreatic injury. Patients with pancreatic injury, 10 cases evolved into pancreatitis, representing 47.6% (10/21) in the pancreatic injury subgroup and 16.1% (10/62) of the total patient cohort. Preemptive treatment was administered to 47.6% (10/21) of patients with pancreatitis, the effective rate was 100%. Among these patients, 70% (7/10) underwent successful rechallenge with ICIs. The occurrence of pancreatic injury was positively correlated with the treatment duration (P < 0.05) but showed no significant correlation with combination therapies (P > 0.05).

CONCLUSION

The likelihood of pancreatic injury increased with longer treatment durations with ICIs; no significant association was found between the incidence of ICIs-related pancreatic damage and combination therapies. Preemptive treatment for immune-related pancreatitis is feasible, allowing some patients to successfully undergo rechallenge with ICIs therapy.

Review article: Contemporary management of gastrointestinal, pancreatic and hepatic toxicities of immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are effective oncologic agents which frequently cause immune-related adverse events (irAEs) which can impact multiple organ systems. Onco-Gastroenterology is a novel and emerging subspecialty within gastroenterology focused on cancer treatment-related complications. Gastroenterologists must be prepared to identify and manage diverse immune-mediated toxicities including enterocolitis, hepatitis, pancreatitis and other ICI-induced toxicities.

AIM

To provide a narrative review of the epidemiology, diagnostic evaluation and management of checkpoint inhibitor-induced gastrointestinal and hepatic toxicities.

METHODS

We searched Cochrane and PubMed databases for articles published through August 2023.

RESULTS

Gastrointestinal and hepatic irAEs include most commonly enterocolitis and hepatitis, but also pancreatitis, oesophagitis, gastritis, motility disorders (gastroparesis) and other rarer toxicities. Guidelines from the National Comprehensive Cancer Network, American Society of Clinical Oncology and European Society for Medical Oncology, in combination with emerging cohort and clinical trial data, offer strategies for management of ICI toxicities. Evaluation of irAEs severity by formal classification and clinical stability, and a thorough workup for alternative etiologies which may clinically mimic irAEs underlie initial management. Treatments include corticosteroids, biologics and other immunosuppressive agents plus supportive care; decisions on dosing, timing and choice of steroid adjuncts and potential for subsequent checkpoint inhibitor dosing are nuanced and toxicity-specific.

CONCLUSIONS

Expanding clinical trial and cohort data have clarified the epidemiology and clinical characteristics of gastrointestinal, pancreatic and hepatic toxicities of ICIs. Guidelines, though valuable, remain based principally on retrospective cohort data. Quality prospective, controlled studies may refine algorithms for treatment and potential immunotherapy rechallenge.

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.

Pancreatic injury in patients treated with immune checkpoint inhibitors: a retrospective multicenterstudy

BACKGROUND

Immune checkpoint inhibitor-related pancreatic injury (ICI-PI) is a rare occurrence, which has not been reported in detail. We conducted a retrospective multicenter study to determine the clinical characteristics, risk factors, and treatment of ICI-PI.

METHODS

We reviewed the medical records of patients who received ICIs for malignant tumors between April 2014 and April 2019 at 16 participating hospitals. Patients with elevated pancreatic enzymes or pancreatitis were identified and classified using the Common terminology Criteria for Adverse Events (CTCAE) ver.5.0). The number of patients with pancreatic enzyme elevation was determined and those with pancreatic enzyme elevation of ≥ grade 3 according to CTCAE ver.5.0, or pancreatitis underwent detailed analysis for ICI-PI.

RESULTS

The study enrolled 1069 patients. Nineteen patients (1.8%) had ICI-PI, 5 (0.5%) of whom also had pancreatitis. Four patients had mild pancreatitis, whereas 1 patient had severe pancreatitis, culminating in death. Steroid therapy was administered to 7 of 19 patients, which led to ICI-PI improvement in 5 patients. On the other hand, ICI-PI improved in 9 of 12 patients who were not administered steroid therapy. Six of the 14 patients with ICI-PI improvement were rechallenged with ICI, and ICI-PI relapse occurred in only 1 patient (16.7%), which improved with ICI discontinuation and steroid therapy.

CONCLUSIONS

ICI-PI is a rare occurrence, with a low incidence of pancreatitis, which followed a very serious course in one patient. Although the benefit of steroid therapy for ICI-PI is unclear, ICI rechallenge is acceptable after improvement of ICI-PI without pancreatitis.

Acute pancreatitis associated with pembrolizumab-induced hypertriglyceridemia

INTRODUCTION

Acute pancreatitis (AP) following drug-induced hypertriglyceridemia is a rare clinical phenomenon. Immune checkpoint inhibitors have revolutionized treatment for a variety of solid organ and hematological malignancies. Pembrolizumab is a programmed cell death receptor-1 (PD-1) inhibitor that has shown promising responses in many advanced cancers. However, a constellation of immune-related adverse events has also been described. There are reports of pembrolizumab-induced hypertriglyceridemia, but AP as a result of this side effect remains an exceedingly rare clinical sequela.

CASE REPORT

We delineate a case of a patient with stage IVB non-small-cell lung cancer who developed progressive abdominal pain and nausea following administration of pembrolizumab for four months. Laboratory studies revealed increased serum lipase and triglyceride levels at 12,562 IU/L and 16,901 mg/dL, respectively. The diagnosis of AP was made based on the revised Atlanta classification criteria. After ruling out alternative causes, pembrolizumab-induced hypertriglyceridemia was considered the likely etiology of AP.

MANAGEMENT AND OUTCOME

The patient was transferred to the medical intensive care unit for close monitoring. Treatment was initiated with intravenous fluids, pain medications, and an insulin infusion. However, her hypertriglyceridemia levels remained persistently elevated, necessitating therapeutic apheresis. She recovered well with no complications after triglyceride apheresis.

DISCUSSION

AP following pembrolizumab-associated hypertriglyceridemia remains a rare clinicopathologic entity. Given the widespread clinical use of immune checkpoint inhibitors, knowledge of such rare adverse events is crucial. Evaluation of serum triglyceride levels before and after initiating pembrolizumab therapy may be mandated, especially in patients with metabolic comorbidities.

Incidence of Pancreatic Injury and Pancreatitis in Patients Treated With Immune Checkpoint Inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are being increasingly used to treat advanced malignancies. ICI-induced pancreatic injury (ICI-PI), which is an immune-related adverse event that may be a risk factor of ICI-associated pancreatitis, is not well documented in the literature.

METHODS

Consecutive patients who received ICIs for advanced malignancies from August 2015 through October 2022 were analyzed for the incidence of ICI-PI based on the Common Terminology Criteria for Adverse Events and ICI-associated pancreatitis. The imaging, clinical, and pathological findings of ICI-associated pancreatitis were also assessed.

RESULTS

This study enrolled 843 patients. In multivariable analyses, dual or simultaneous immunotherapy and ≥10 cycles of ICI administration were significant predictive factors for all grades of pancreatic injury, including grade ≥3. Notably, patients who received simultaneous immunotherapy exhibited a higher incidence of grade ≥3 pancreatic injuries compared with those receiving asynchronous immunotherapy in univariable analysis ( P = 0.032). One-fifth of the patients (16/70) with grade ≥3 pancreatic injuries had imaging evidence of pancreatitis similar to mild acute pancreatitis. ICI-associated pancreatitis was observed in 5.7% (48/843) of patients, including 1.8% (15/843) with moderate-to-severe pancreatitis (grade ≥2). Symptomatic cases (0.36%, 3/843) were treated with steroids with favorable outcomes. Immunohistochemistry for CD4 and CD8 revealed greater infiltration of CD8 + than CD4 + lymphocytes.

DISCUSSION

Simultaneous immunotherapy and dual immunotherapy are risk factors of ICI-PI. Although most patients diagnosed with ICI-PI and ICI-associated pancreatitis were asymptomatic and had a low mortality likelihood, long-term outcomes, including endocrine and exocrine function, should be carefully monitored.

Immune Checkpoint Inhibitor-induced Pancreatitis with Pancreatic Enlargement Mimicking Autoimmune Pancreatitis: A Case Report and Review of the Literature

A 61-year-old woman was administered 35 cycles of pembrolizumab for the treatment of recurrent endometrial cancer, achieving a complete response. She presented with asymptomatic pancreatic enlargement and elevated hepatobiliary enzymes, but amylase and lipase levels were within the normal ranges. Intrapancreatic bile duct stenosis due to pancreatic enlargement was present, mimicking autoimmune pancreatitis on computed tomography performed before the onset of clinical manifestations. A histological examination of a biopsy specimen showed lymphocyte and plasma cell infiltration with dense fibrosis in the stroma. The patient was successfully treated with oral prednisolone. There were no manifestations of recurrent pancreatitis after tapering the prednisolone dose.

Autoimmune pancreatitis: Biopsy interpretation and differential diagnosis

Autoimmune pancreatitis (AIP) is classified into type 1 (IgG4-related) and type 2 (IgG4-unrelated) and the interpretation of pancreatic biopsy findings plays a crucial role in their diagnosis. Needle biopsy of type 1 AIP in the acute or subacute phase shows a diffuse lymphoplasmacytic infiltrate, storiform fibrosis, obliterative phlebitis, and the infiltration of many IgG4-positive plasma cells. In a later phase, changes become less inflammatory and more fibrotic, making interpretations more challenging. Confirmation of the lack of 'negative' findings that are unlikely to occur in type 1 AIP (e.g., neutrophilic infiltration, abscess) is important to avoid an overdiagnosis. The number of IgG4-positive plasma cells increases to >10 cells/high-power field (hpf), and the IgG4/IgG-positive plasma cell ratio exceeds 40 %. However, these are minimal criteria and typical cases show >30 positive cells/hpf and a ratio >70 % even in biopsy specimens. Therefore, cases with a borderline increase in this number or ratio need to be diagnosed with caution. In cases of ductal adenocarcinoma, the upstream pancreas rarely shows type 1 AIP-like changes; however, the ratio of IgG4/IgG-positive plasma cells is typically <40 %. Although the identification of a granulocytic epithelial lesion (GEL) is crucial for type 2 AIP, this finding needs to be interpreted in conjunction with a background dense lymphoplasmacytic infiltrate. An isolated neutrophilic duct injury can occur in peritumoral or obstructive pancreatitis. Drug-induced pancreatitis in patients with inflammatory bowel disease often mimics type 2 AIP clinically and pathologically. IL-8 and PD-L1 are potential ancillary immunohistochemical markers for type 2 AIP, requiring validation studies.

Autoimmune pancreatitis: Cornerstones and future perspectives

Autoimmune pancreatitis (AIP) is an autoimmune subtype of chronic pancreatitis resulting from the aberrant immune response against the pancreas, leading to inflammation and fibrosis. Although AIP is rare, its incidence is increasing and is often misdiagnosed as other pancreatic diseases. AIP is commonly classified into two types. Type 1 AIP (AIP-1) is typically associated with elevated serum immunoglobulin G4 (IgG4) levels and systemic manifestations, while type 2 AIP is typically a more localized form of the disease, and may coexist with other autoimmune disorders, especially inflammatory bowel diseases. Additionally, there is emerging recognition of a third type (type 3 AIP), which refers to immunotherapy-triggered AIP, although this classification is still gaining acceptance in medical literature. The clinical manifestations of AIP mainly include painless jaundice and weight loss. Elevated serum IgG4 levels are particularly characteristic of AIP-1. Diagnosis relies on a combination of clinical, laboratory, radiological, and histological findings, given the similarity of AIP symptoms to other pancreatic disorders. The mainstay of treatment for AIP is steroid therapy, which is effective in most cases. Severe cases might require additional imm-unosuppressive agents. This review aims to summarize the current knowledge of AIP, encompassing its epidemiology, etiology, clinical presentation, diagnosis, and treatment options. We also address the challenges and controversies in diagnosing and treating AIP, such as distinguishing it from pancreatic cancer and managing long-term treatment, highlighting the need for increased awareness and knowledge of this complex disease.

Exocrine Pancreatic Insufficiency Induced by Immune Checkpoint Inhibitors

BACKGROUND

Scant data describe exocrine pancreatic insufficiency (EPI) secondary to immune checkpoint inhibitor (ICI) use. The goal of this study is to describe the incidence, risk factors, and clinical characteristics of patients with ICI-related EPI.

PATIENTS AND METHODS

A single center, retrospective case-control study was performed of all ICI-treated patients at Memorial Sloan Kettering Cancer Center between January 2011 and July 2020. ICI-related EPI patients had steatorrhea with or without abdominal discomfort or weight loss, started pancrelipase after initiation of ICI, and demonstrated symptomatic improvement with pancrelipase. Controls were matched 2:1 by age, race, sex, cancer type, and year of ICI start.

RESULTS

Of 12 905 ICI-treated patients, 23 patients developed ICI-related EPI and were matched to 46 controls. The incidence rate of EPI was 1.18 cases per 1000 person-years and the median onset of EPI was 390 days after the first dose of ICI. All 23 (100%) EPI cases had steatorrhea that improved with pancrelipase, 12 (52.2%) had weight loss, and 9 (39.1%) had abdominal discomfort; none had changes of chronic pancreatitis on imaging. Nine (39%) EPI patients had episodes of clinical acute pancreatitis preceding the onset of EPI, compared to 1 (2%) control (OR 18.0 (2.5-789.0), P < .001). Finally, the EPI group exhibited higher proportions of new or worsening hyperglycemia after ICI exposure compared with the control group (9 (39.1%) vs. 3 (6.5%), P < .01).

CONCLUSION

ICI-related EPI is a rare but clinically significant event that should be considered in patients with late onset diarrhea after ICI treatment and often is associated with development of hyperglycemia and diabetes.

Pancreatitis as immune-related adverse event during pembrolizumab therapy for multiple lung metastases from renal pelvic cancer

Introduction

Pembrolizumab administration has become the standard of care for patients with urothelial carcinoma, though a variety of adverse events have been reported. Presented here is a rare case of pancreatitis that occurred as an immune-related adverse event.

Case presentation

An 81-year-old man undergoing treatment with pembrolizumab for multiple lung metastases from renal pelvic cancer was presented with a fever and diagnosed with pancreatitis based on elevated pancreatic enzyme levels and imaging findings. There was no history of alcohol consumption or findings indicating gallstones, elevated liver enzymes, or abdominal complications. The patient was diagnosed with immune-related adverse event pancreatitis and treated with Lactate Ringer's solution (3000 mL/day) and steroids, during which his condition improved.

Conclusion

Although pancreatitis is a rare complication, it should always be considered as a potential immune-related adverse event in patients treated with an immune checkpoint inhibitor such as pembrolizumab.

Immune Checkpoint Inhibitor-Induced (Type 3) Autoimmune Pancreatitis

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICI) have revolutionized cancer care and work primarily by blocking CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), and/or PD-1 (programmed cell death protein 1), and/or PD-L1 (programmed death-ligand 1), thereby providing highly efficacious anti-tumor activity. However, this unmitigated immune response can also trigger immune related adverse events (irAEs) in multiple organs, with pancreatic irAEs (now referred to as type 3 Autoimmune pancreatitis (AIP) being infrequent.

RECENT FINDINGS

Type 3 AIP is a drug-induced, immune mediated progressive inflammatory disease of the pancreas that may have variable clinical presentations viz., an asymptomatic pancreatic enzyme elevation, incidental imaging evidence of pancreatitis, painful pancreatitis, or any combination of these subtypes. Management is largely supportive with intravenous fluid hydration, pain control and holding the inciting medication. Steroids have not been shown to demonstrate a clear benefit in acute management. A rapid development pancreatic atrophy is observed on imaging as early as 1 year post initial injury. Type 3 AIP is a chronic inflammatory disease of the pancreas that though predominantly asymptomatic and mild in severity can lead to rapid organ volume loss regardless of type of clinical presentation and despite steroid therapy.

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.

PET/CT molecular imaging in the era of immune-checkpoint inhibitors therapy

Cancer immunotherapy, especially immune-checkpoint inhibitors (ICIs), has paved a new way for the treatment of many types of malignancies, particularly advanced-stage cancers. Accumulating evidence suggests that as a molecular imaging modality, positron emission tomography/computed tomography (PET/CT) can play a vital role in the management of ICIs therapy by using different molecular probes and metabolic parameters. In this review, we will provide a comprehensive overview of the clinical data to support the importance of 18F-fluorodeoxyglucose PET/CT (18F-FDG PET/CT) imaging in the treatment of ICIs, including the evaluation of the tumor microenvironment, discovery of immune-related adverse events, evaluation of therapeutic efficacy, and prediction of therapeutic prognosis. We also discuss perspectives on the development direction of 18F-FDG PET/CT imaging, with a particular emphasis on possible challenges in the future. In addition, we summarize the researches on novel PET molecular probes that are expected to potentially promote the precise application of ICIs.

The diagnosis of immune-related pancreatitis disguised as multifocal lesions on MRI by endoscopic ultrasound-guided fine-needle biopsy: A case report

Immune checkpoint inhibitor (ICI)–related acute pancreatitis (irAP) is a rare, potentially life-threatening immune-related adverse event. Whereas CT and MRI remain first-line diagnostic imaging modalities, more patients are presenting with atypical irAP as ICI use increases. To appropriately manage these events, it is important to catalog these presentations and provide comprehensive clinical, radiological, and pathological descriptions to guide evidence-based practice. Here, we present the case of a 66-year-old man with advanced lung adenocarcinoma who, after the fifth course of toripalimab, developed epigastric discomfort and elevated serum amylase and lipase. irAP was suspected, but MRI revealed atypical, multifocal pancreatic lesions. To exclude metastases, an endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) was performed. EUS revealed a slightly swollen pancreas with heterogeneous echoic signals and scattered hyperechoic areas in the parenchyma without an obvious mass. Histopathological examination of the FNB revealed retention of the normal lobular pancreatic architecture with focal acinar atrophy associated with a CD8⁺ T lymphocyte-predominant infiltrate, further confirming the diagnosis of irAP. After starting glucocorticoids, his symptoms resolved, serum amylase and lipase rapidly decreased to normal, and the abnormal MRI features diminished. irAP can, therefore, present as multifocal lesions on MRI, and, when metastatic disease requires exclusion, EUS-FNB is an effective way to establish a definitive diagnosis. Refining the histopathological and immunopathological criteria for the diagnosis of irAP is now warranted.

Pancreatic injury following immune checkpoint inhibitors: A systematic review and meta-analysis

Background: Pancreatic injury (pancreatitis, amylase/lipase elevation) is a rare adverse event of immune checkpoint inhibitors (ICIs). With the high number of clinical studies on ICIs, the incidence and characteristics of associated pancreatic injury (PI) need to be reevaluated.

Methods: A systematic review and meta-analysis was conducted to assess the incidence of PI in cancer patients who received ICIs in randomized controlled trials (RCTs). PubMed, Embase, the ASCO, ESMO, and AACR conference proceedings before 1 April 2022, were investigated for relevant research.

Results: 50 RCTs involving 35,223 patients were included. The incidence of ICIs-PI was 2.22% (95% CI = 1.94%–2.53%). The incidence of PI was 3.76% (95% CI = 1.84–7.67%) when combining two ICIs, which was higher than single ICIs [2.25% (95% CI = 1.91–2.65%)]. The ICIs were ranked from high to low based on PI incidence: PD-L1 inhibitors 3.01% (95% CI = 1.86–4.87%), CTLA-4 inhibitors 2.92% (95% CI = 0.99–8.65%) and PD-1 Inhibitor 2% (95% CI = 1.67–2.39%). The ICI with the highest rate of PI was pembrolizumab 7.23.% (95% CI = 1.69–30.89%). In addition, the incidence of severe ICIs-PI was 2.08% (95% CI = 1.76–2.46%); and the incidence of severe PI was 2.32% (95% CI = 1.76–3.06%) when combining two ICIs, which was higher than single ICI [1.95% (95% CI = 1.58–2.41%)]. The ICIs were ranked from high to low according to the incidence of severe PI: PD-L1 inhibitors 3.1% (95% CI = 1.7–5.64%), CTLA-4 inhibitors 2.69% (95% CI = 0.76–9.49%), PD-1 inhibitors 1.80% (95% CI = 1.41–2.29%).

Conclusion: Treatment with multiple ICIs result in a higher incidence of PI compared to single ICIs, irrespective of the grade of pancreatic injury. The incidence of PI caused by PD-L1 inhibitors is higher than that of CTLA-4 inhibitors and PD-1 Inhibitor, and Pembrolizumab has the highest rate of ICIs-PI. Although the incidence of ICIs-PI is not high, they are usually severe (≥ grade 3 events).

Type 3 autoimmune pancreatitis (immune checkpoint inhibitor-induced pancreatitis)

PURPOSE OF REVIEW

Type 3 auto-immune pancreatitis (AIP) is a rare immune-related adverse event (irAE) because of immune checkpoint inhibitor (ICI) therapy employed in the management of advanced malignancies. The evaluation and management of this disease entity is not well documented in the literature. We summarize the available information on the clinical profile, diagnosis, and treatment of this disorder.

RECENT FINDINGS

ICI-pancreatic injury (ICI-PI) is a form of AIP, recently termed type 3 AIP, which may present as an asymptomatic lipase elevation or clinical pancreatitis, that is, abdominal pain and elevated lipase. CT findings of pancreatitis may be absent in some cases. Diagnosis is based on a temporal relationship to ICI exposure and the absence of other cause of pancreatitis. Combination ICIs increase the risk of type 3 AIP compared with ICI monotherapy. Though corticosteroids are used for ICIP, their role and benefit remain unclear to date. Holding immunotherapy carries the risk of progression of underlying cancer.

SUMMARY

ICI-PI is a unique form of AIP (type 3) with a distinct disease profile. The majority of patients with ICIPI are asymptomatic and steroid therapy has unclear benefits.

Adverse effects under immune checkpoint inhibitors on [18F]FDG PET/CT imaging

Despite their undisputed contribution to the management of various tumors and the prolongation of patient survival, immune checkpoint inhibitors (ICIs) exert their effect at the cost of toxicity. In the context of the activation of the host immune system triggered by ICIs, collateral, inflammatory side effects, commonly addressed as immune-related adverse events (irAEs) often occur. Early detection of irAEs can be critical for adequate decisions on patient management that may subsequently improve patient outcome. Moreover, the emergence of irAEs has been linked with the antitumor effect elicited by ICIs, thus, their identification may potentially provide prognostic information. Although the diagnosis of irAEs is mainly clinical, some adverse events may be asymptomatic and only diagnosed by imaging modalities. At the same time, radiological signs of irAEs are not necessarily associated with clinical symptoms, however, clinicians should be alerted to their presence. Among imaging modalities [¹⁸F]FDG PET/CT has shown satisfying efficiency in response assessment and monitoring of ICIs' treatment, especially in patients suffering from metastatic melanoma and lung cancer. In this context, [¹⁸F]FDG PET/CT may also be a valuable method for surveillance of irAEs during immunotherapy. This article aims to review the most common adverse events observed on [¹⁸F]FDG PET/CT under immunotherapy and summarize potential results linking PET signs of irAEs with response assessment to ICIs.

Imaging features of toxicities associated with immune checkpoint inhibitors

The past decade has witnessed a change in landscape of cancer management with the advent of precision oncology. Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and have played an important role in improving patient survival. While the patients are living longer, treatment with ICIs are sometimes associated with adverse effects, some of which could be fatal. Radiologists can play a crucial role by early identification of some of these adverse effects during restaging scans. Our paper focuses on the imaging features of commonly occurring ICI toxicities based on organ system.

A Decade of Success in Melanoma Immunotherapy and Targeted Therapy: What Every Radiologist Should Know

ABSTRACT

Treatment strategies for malignant melanoma have rapidly evolved over the past decade. Because of its propensity to develop advanced stage and metastatic disease, melanoma has contributed to the majority of mortalities among patients with skin cancer. The development of novel therapeutics such as immunotherapy and targeted molecular therapies has revolutionized the treatment of patients with advanced stage and metastatic malignant melanoma. Immune checkpoint inhibitors, BRAF/MEK inhibitors, and other revolutionary therapies have demonstrated remarkable success in the treatment of this common malignancy. Along with these advancements in systemic therapies, imaging has continued to play a critical role in the diagnosis and follow-up of patients with malignant melanoma. As the use of these novel therapies continues to expand, knowledge of the evolving therapeutic landscape of melanoma is becoming critical for radiologists. In this review, we provide a primer for radiologists outlining the evolution of immunotherapy and targeted therapy in the treatment of melanoma. We discuss the critical role of imaging in evaluation of treatment response, including a summary of current imaging response guidelines. Last, we summarize the essential role of imaging in the evaluation of potential adverse events seen in patients with malignant melanoma undergoing treatment with immune checkpoint inhibitors.

Clinical Characteristics of ICI-Related Pancreatitis and Cholangitis Including Radiographic and Endoscopic Findings

The indications for immune checkpoint inhibitors (ICIs) have expanded to include carcinomas of various organs. However, as ICI therapy expands, the management of immune-related adverse events (irAEs) has become a problem. ICI-related pancreatitis and cholangitis are relatively rare irAEs. Although some patients with ICI-related pancreatitis and cholangitis are asymptomatic and do not require treatment, there have been reports of patients who did not respond to immunosuppressive therapy and died. Thus, the pathogenesis of ICI-related pancreatitis and cholangitis should be clarified immediately. Currently, the role of endoscopy in the diagnosis and treatment of inflammatory pancreatic and biliary duct diseases is becoming increasingly important. In this review, we summarize clinical characteristics as well as radiographic and endoscopic findings of ICI-related pancreatitis and cholangitis.

Fatal Immune Checkpoint Inhibitor-related Pancreatitis

We herein report a case of fatal pancreatitis induced by an immune checkpoint inhibitor. A 62-year-old man with cancer of unknown primary was treated with pembrolizumab. After 12 cycles, immune-related pneumonitis developed and was treated with prednisolone. Three months later, pancreatitis developed, which was successfully treated with hydration and protease inhibitors. Eight months later, another attack of pancreatitis occurred, which did not respond to therapy, including high-dose corticosteroids, and he eventually died. This is the first report describing fatal immune checkpoint inhibitor-related pancreatitis. Despite the rarity of this complication, attention should be paid to its potential severity and treatment.

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.

Pembrolizumab-induced autoimmune side effects of colon and pancreas in a patient with lung cancer

Immune checkpoint inhibitors have been shown to be effective for treating many carcinomas. However, the activated immune response may lead to the development of multiple immune-related adverse events, including rare immune-mediated inflammation due to autoimmune mechanisms. An 82-year-old man was diagnosed with large cell lung cancer (T1aN3M1 stage IVB) and was treated with inhibitors of the programmed cell death receptor-1, pembrolizumab. Diarrhea and melena occurred after six doses of pembrolizumab, and colonoscopy revealed mucosal inflammation of the rectum and sigmoid colon in a continuous manner, resembling the typical endoscopic findings of ulcerative colitis. Subsequently, fever and hyperamylasemia appeared, and the patient was diagnosed with pancreatitis resembling type 2 autoimmune pancreatitis on imaging tests and cytological examination, which showed infiltration of inflammatory cells, mainly neutrophils. Steroid therapy was administered and both, colitis and pancreatitis markedly improved. Here, we present a patient who developed colitis and pancreatitis after ICI treatment for advanced lung cancer. Both are thought to be due to autoimmune side effects of pembrolizumab. Although pancreatitis is a rare irAE, clinicians should be aware of the development of pancreatitis, especially in the case of irAE colitis resembling ulcerative colitis.

Expected and non-expected immune-related adverse events detectable by CT

PURPOSE

Cancer treatments with immune checkpoint inhibitors (ICI) are associated with a unique set of drug toxicities called immune-related adverse events (irAES). The aim of the present study was to describe the radiological manifestation of irAES detectable by CT.

METHOD

Retrospective analysis of 284 patients treated with ICI for various types of advanced cancer; of them, 129 patients were selected, all having been treated with single-agent ICI, and all with a baseline CT scan and follow-up scans available at our Institute. CT examinations were reviewed by two radiologists involved in the study with a consensus reading. Imaging findings consistent with irAES were reported and correlated with clinical-laboratory data.

RESULTS

Immune-related adverse events were found in 25/129 (19.4 %) patients. No statistically significant differences were found in either the prevalence of irAES or in the time of onset of tumour type. Thoracic complications were detected in 14/25 (56.0 %) patients consisting in: 3 radiation recall pneumonia, 3 Transient Asymptomatic Pulmonary Opacities (TAPOs), 3 hypersensitivity pneumonia, 2 diffuse alveolar damage, 2 organizing pneumonia, 1 sarcoid-like reaction. In the remaining 11/25 (44.0 %), there were extra-pulmonary complications: 3 colitis, 4 cholecystitis, 2 pancreatitis and 2 cases of visceral ischemia.

CONCLUSIONS

Radiologists should be aware of the wide spectrum of irAES as they could affect the outcome. Pneumonia is the most frequent irAES; however, the international classification for interstitial lung disease does not seem to be capable of describing all possible drug-related pulmonary toxicities. Additional findings included TAPOs, radiation recall pneumonia and sarcoid-like reaction.

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.