Usefulness of 18F-FDG PET-CT in the Management of Febrile Neutropenia: A Retrospective Cohort from a Tertiary University Hospital and a Systematic Review

Is neutropenia still the main risk factor for invasive aspergillosis? A contemporary university hospital retrospective cohort of invasive aspergillosis in neutropenic and non-neutropenic patients

INTRODUCTION

In times of mold active prophylaxis, invasive aspergillosis (IA) epidemiology is evolving. Presentation in non-neutropenic may differ from neutropenic. We investigated the cases of IA in our center with a focus on differences between neutropenic and non-neutropenic, and analyzed the impact of cryptic and non-fumigatus Aspergillus species.

METHODS

Retrospective observational study including all adult patients admitted to the Puerta de Hierro-Majadahonda Hospital between January 2018 and April 2024 with IA.

RESULTS

112 IA were identified. Only 11 (9.8%) had neutropenia as risk factor for IA. Most frequent risk factors were corticosteroids (77.2%), SOT (46.5%), SARS-CoV2 (29.7%) and CMV replication (28.7%). 89.3% were pulmonary IA with 6 cases (5.4%) of disseminated infection. A. fumigatus was the most frequent species 48 (51.6%). 13 cases (14%) were caused by cryptic Aspergillus spp. Non-neutropenic patients, compared to neutropenic patients, were more likely to have positive fungal cultures (83.2% versus 54.5%, p = 0.023[NS]), and not to present a halo sign (7.4% versus 45.5%, p = 0.003 [NS]). In addition, in non-neutropenic patients, compared to neutropenic patients, there was a trend towards a greater probability of positive GM from BAL (81.3% versus 66.7%, p = 0.304) and a trend towards a lower probability of positive serum GM (25.7% versus 45.5%, p = 0.137). 41/112 (36.6%) cases presented breakthrough IFI and in 51.2%, (21/41 cases), the isolate was resistant to the prior antifungal. One presented A. fumigatus with the TR34-L98H mutation.

CONCLUSION

Risk factors different than neutropenia are currently the most common in IA. The clinical presentation in non-neutropenic patients differs from neutropenic. Resistance to antifungals is emerging especially in breakthrough IA.

What do we know About the Usefulness of 18F-FDG PET-CT for the Management of Invasive Fungal Infection? An International Survey

BACKGROUND

Recent data support 18F-FDG PET-CT for the management of infections in immunocompromised patients, including invasive fungal infection (IFI). However, its role is not well established in clinical practice. We performed an international survey to evaluate the knowledge of physicians about the usefulness of 18F-FDG PET-CT in IFI, in order to define areas of uncertainty.

METHODS

An online survey was distributed to infectious diseases working groups in December 2023-January 2024. It included questions regarding access to 18F-FDG PET-CT, knowledge on its usefulness for IFI and experience of the respondents. A descriptive analysis was performed.

RESULTS

180 respondents answered; 60.5% were Infectious Diseases specialists mainly from Spain (52.8%) and Italy (23.3%). 84.4% had access to 18F-FDG PET-CT at their own center. 85.6% considered that 18F-FDG PET-CT could be better than conventional tests for IFI. In the context of IFI risk, 81.1% would consider performing 18F-FDG PET-CT to study fever without a source and around 50% to evaluate silent lesions and 50% to assess response, including distinguishing residual from active lesions. Based on the results of the follow-up 18F-FDG PET-CT, 56.7% would adjust antifungal therapy duration. 60% would consider a change in the diagnostic or therapeutic strategy in case of increased uptake or new lesions. Uncovering occult lesions (52%) and diagnosing/excluding endocarditis (52.7%) were the situations in which 18F-FDG PET-CT was considered to have the most added value. There was a great variability in responses about timing, duration of uptake, the threshold for discontinuing treatment or the influence of immune status.

CONCLUSION

Although the majority considered that 18F-FDG PET-CT may be useful for IFI, many areas of uncertainty remain. There is a need for protocolized research to improve IFI management.