Radiologic Predictors of Disease Recurrence in Nasopharyngeal Carcinoma: A Retrospective Evaluation of MRI and 18F-FDG-PET/CT Parameters

<b>Background/Objectives:</b> NPC is a radiosensitive malignancy with high recurrence rates despite therapeutic advances. This study aimed to identify radiologic and metabolic predictors of recurrence in newly diagnosed NPC by integrating MRI and ¹⁸F-FDG PET/CT parameters. <b>Methods:</b> Fifty-two patients with biopsy-proven, previously untreated NPC who underwent pre-treatment MRI and ¹⁸F-FDG PET/CT were retrospectively analyzed. Local tumor features, nodal status, and response patterns were evaluated using MRI and PET/CT-derived metrics: SUVmax, SUVmean, SUVpeak, MTV, and TLG. The post-treatment MRI response was categorized into six patterns. Univariate and multivariate analyses were performed to identify independent predictors. <b>Results:</b> Recurrence occurred in 27% of patients. Based on the multivariate analysis, PNI, extensive PPS invasion, GTV, and metastatic LN count were identified as independent predictors of recurrence (PNI: OR = 1.60, <i>p</i> = 0.029; PPS: OR = 1.23, <i>p</i> = 0.027; GTV: OR = 1.08, <i>p</i> = 0.042; LN count: OR = 1.20, <i>p</i> = 0.031). PNI and PPS invasion were significantly associated with local failure (HR = 8.21, <i>p</i> = 0.008 and HR = 3.52, <i>p</i> = 0.043, respectively). GTV was independently associated with an increased risk of local (HR = 1.14, <i>p</i> = 0.021) and distant recurrence (HR = 1.19, <i>p</i> = 0.024). The presence of metastatic disease at diagnosis (HR = 6.27, <i>p</i> = 0.027) and a higher LN count (HR = 1.17, <i>p</i> = 0.028) were also linked to distant failure. <b>Conclusions:</b> Imaging-derived predictors including GTV, PNI, LN burden, and MRI-based response patterns demonstrate prognostic value for disease recurrence in NPC and may guide risk-adapted treatment strategies.