Prognostic significance of normalized distance from maximum standardized uptake value to tumor centroid on [18F]FDG PET/CT in head and neck squamous cell carcinoma.

Objective: The maximum [¹⁸F]FDG uptake of a cancer lesion has been found to relocate from the center to the periphery during progression. This behavior suggests that the normalized distances from the hotspot of radiotracer uptake to the tumor centroid (NHOC) and to the tumor perimeter (NHOP) could serve as novel geometric PET parameters indicative of tumor aggressiveness. This study aimed to explore the prognostic relevance of NHOC and NHOP in [¹⁸F]FDG PET/CT for predicting the response to concurrent chemoradiotherapy (CCRT) and progression-free survival (PFS) in patients with head and neck squamous cell carcinoma (HNSCC).

Materials and methods: We retrospectively reviewed 116 HNSCC patients who received CCRT and were assessed with pre-treatment (PET1) and three months post-treatment PET/CT (PET2). Along with conventional PET parameters, NHOC and NHOP for primary tumors on PET1 and the percent changes in NHOC and NHOP between PET1 and PET2 were measured.

Results: Of all the PET1 parameters assessed, NHOC was the most effective in predicting the CCRT response, achieving an area under the receiver operating characteristic curve of 0.645. In multivariate logistic regression and survival analysis, NHOC identified as an independent predictor for both complete metabolic response (P = .028) and PFS (P = .006). In a subgroup of 46 patients exhibiting residual primary tumors on PET2, both the percent changes in NHOC (P = .048) and NHOP (P = .041) were significantly associated with PFS.

Conclusions: NHOC and the percent changes in NHOC and NHOP following CCRT may serve as effective [¹⁸F]FDG PET/CT parameters for predicting clinical outcomes in HNSCC patients.