371P - The role of FDG-PET/CT in the assessment of response to radiation therapy in head and neck cancers: A systematic review and meta-analysis

Background

Head and neck cancers (HNCs) are a challenging disease to treat due to their anatomical complexity and high propensity for locoregional recurrence. Radiation therapy is a crucial component of treatment approach for HNCs. However, assessing the response to therapy can be difficult, particularly in the early post-treatment period. Positron emission tomography (PET) with the glucose analogue [18F] fluorodeoxyglucose (FDG) has shown promising results in the assessment of treatment response in HNCs. Therefore, this systematic review is written to evaluate the role of FDG-PET/CT in the assessment of response to radiotherapy in HNCs.

Methods

A comprehensive search of electronic databases was conducted, including EMBASE, Scopus, Pubmed, PMC, and Science Direct from inception to April 2023. Studies were included if they reported on the use of FDG-PET/CT for assessing treatment response in HNCs treated with radiation therapy. Quality assessment using Newcastle-Ottawa Scale and data extraction were performed independently by three reviewers.

Results

16 studies reporting on a total of 348 patients were included in this analysis. The data assessed in the included studies were diverse, including the evaluation of the diagnostic performance of FDG-PET/CT, the comparison with conventional imaging techniques, the ability to avoid neck dissections, or assessed which patient population would derive most benefit from post-treatment FDG-PET/CT scan. Despite their diversity, almost all studies have showed that FDG-PET/CT scan is a reliable method to evaluate residual or recurrent tumour within 6 months post-(chemo)radiation therapy with pooled sensitivity of 84% and pooled specificity of 90%. There was a moderate risk of bias due to selection bias. Also, confirmation of positive nodal disease at the time of diagnosis and prior to therapy is an important shortcoming in most included studies.

Conclusions

FDG-PET/CT within 6 months after (chemo)radiotherapy in HNCs patients is a reliable method for ruling out residual/recurrent nodal disease and obviates the need for therapeutic intervention. However, further standardization of the PET technique is required.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.