To our knowledge, this is the most comprehensive analysis of ICI-mediated pericardial disease reported to date.
The incidence of ICI mediated pericardial disease remains unknown. Prior systematic reviews and retrospective studies of patients treated with ICIs have reported varied incidence and prevalence rates.1,5,6 Patients with ICI mediated pericarditis in these studies were often males with lung cancer, and nivolumab and pembrolizumab were the two most common ICIs used.1,7,8 Similarly, in our cohort, we found ICI-associated pericardial disease predominantly affects males, accounting for 72% of cases, with a median age of 63 years. Lung cancer (adenocarcinoma and squamous cell carcinoma) was the most common cancer in our cohort (81% of cases). In a study of 60 patients with advanced NSCLC receiving immunotherapy with either Nivolumab or Pembrolizumab, pericardial effusion was found to be a relatively common complication occurring in 7% of patients.5 We observed that the PD-1 inhibitors Nivolumab and Pembrolizumab were the most commonly implicated ICIs, used in 61% and 34% of cases, respectively.
Understanding the timeframe for the development of pericardial effusion after ICI initiation is crucial for timely diagnosis and management. Our study revealed an average time to onset of pericardial effusion after 4 cycles of ICI therapy. Prior studies have reported ranges as wide as 1 to 12 months.1,8,9 Sawada et al reported a case of a 67-year-old man who developed pericardial effusion which resolved with corticosteroids after 94 cycles of Nivolumab.11 Overall, this suggests that pericarditis may be a risk during any cycle of ICI therapy.
Dyspnea and chest pain were the most reported symptoms in our study. Remarkably, only 19% of patients exhibited ECG abnormalities, and a minority displayed physical exam abnormalities, such as lower extremity edema (5%) and pericardial rub (2%). These findings underscore the occult nature of pericardial disease in cancer patients undergoing immunotherapy. Given the poor sensitivity of ECG and physical examination in detecting ICI-mediated pericardial disease, our findings suggest the necessity of a low threshold for further diagnostic imaging when patients present with symptoms. The wide range of reported incidence in previous studies likely reflects the under-diagnosis of pericardial effusion when limited to cases requiring drainage.8
Currently, there are limited prognostic tools to suggest development of ICI-mediated pericardial disease, our findings highlight the importance of continued surveillance throughout the course of treatment as there can be a significant delay from therapy initiation and the development of pericardial disease.12 Current data suggests baseline EKG and serial troponin measurement to monitor for development.13–15
Despite the assistance of imaging, the diagnosis of ICI-mediated pericardial disease is complex. Causes of effusion including cancer progression, pseudo progression, or infection are other possibilities in this patient population complicating appropriate diagnosis.16 Progression and pseudo progression can be particularly difficult to distinguish from ICI-mediated pericarditis, as patients may present with effusion and imaging evidence of tumor pseudo-growth due to inflammation from response to therapy.17
Interestingly, of 25 patients who underwent cytological testing of their effusions, 11 tested positive for malignant cells. Similarly, Gong et al reported 8 of 15 patients who underwent pericardiocentesis for ICI mediated pericardial effusion had malignant cells present on cytology.10 This finding suggests that pericardial effusion due to ICI may have malignant cells, and that consideration of the overall clinical picture is necessary for accurate diagnosis and differentiation from the similar but distinct entities of malignant pericardial effusion and pseudo progression.
A substantial portion of patients in our study, 68%, required pericardiocentesis, with 41% experiencing cardiac tamponade. These rates mirror those reported in prior studies, underscoring the significant morbidity and mortality associated with pericardial effusion in ICI-treated patients.16 Almost all patients, 92%, had symptomatic improvement with cessation of ICI. ICI therapy was resumed in 38% of patients, and half of these patients experienced recurrence of pericardial effusion. Over a median follow up of 210 days, the mortality rate amongst patients with pericardial effusion was 16%. Gong et al found that patients treated with ICI who developed pericardial effusion had an increased risk of mortality (Hazard Ratio: 1.53) compared with those who did not.10 Thus, the development of ICI mediated pericardial effusion may be a poor prognostic factor for survival.18
Despite our best efforts, our review is not without several limitations. The entirety of our cohort was derived from case reports with inherent publication bias present. Our analysis may overestimate the severity of this condition as severe case are more likely to be reported. Additionally, given the lack of a control group, our results have limited generalizability.