55 Outcomes of FDG PET-CT in Surveillance of Residual Nodal Metastases Following Non-Surgical Management of Head and Neck Squamous Cell Carcinoma: A Retrospective Review

Abstract

Abstract Aim Assessing the role of positron emission tomography-computed tomography (PET-CT) surveillance in detecting residual disease in nodal metastasis, following non-surgical treatment of Head and neck squamous cell carcinoma (HNSCC), such as chemoradiotherapy or radical radiotherapy. To analyse differences in outcomes between HPV positive and HPV negative cancers. Method Retrospective analysis of 327 patients in South Wales, with histologically proven HNSCC was conducted. All patients were treated non-surgically and post-treatment PET-CT scans were obtained. Patients with PET-CT showing incomplete responses had further analysis of outcomes assessed via surgical histology of the nodes. Outcomes in patients with p16 positive disease were recorded to determine outcomes in HPV positive individuals. Results 64 individuals had residual nodal tumours according to PET-CT. 18 out of 43 patients had a negative histology for malignancy, of which 12 showed p16 positive disease. PET-CT showed a false positive in 41.8% of patients, with a positive predictive value of 58%. 225 patients in total were p16 positive, and 38 out of the 64 residual patients had p16 positive disease. There was no significant difference in outcomes between p16 positive and negative patients. Conclusions Our study concurs with similar literature, that primary CRT in N2 and N3 nodal metastasis followed by PET-CT surveillance minimises unnecessary neck dissections and triple modality treatment. Further research needs to be conducted however, to determine the efficacy of PET-CT surveillance compared to planned neck dissections. Furthermore, outcomes in p16 positive patients requires additional ongoing research to best determine surveillance techniques and long-term health outcomes.