Diagnostic Accuracy of ¹⁸F‐FDG‐PET/CT and ¹⁸F‐FDG‐PET/MRI in Detecting Locoregional Recurrence of HNSCC 12 Weeks after the End of Chemoradiotherapy: Single‐Center Experience with PET/MRI

Abstract

Purpose. In head and neck squamous cell carcinoma (HNSCC), the early diagnosis and efficient detection of recurrences and/or residual tumor after treatment play a very important role in patient’s prognosis. Positron emission tomography (PET) using 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG) has become an established method for the diagnosis of suspected recurrence in head and neck carcinomas. In particular, integrated PET/MRI imaging that provides optimal soft tissue contrast and less dental implant artifacts compared to PET/CT is an intriguing technique for the follow-up imaging of HNSCC patients. The aim of this study was to evaluate the benefit of PET/MRI compared to PET/CT in post-treatment follow-up imaging of HNSCC patients. Methods. This retrospective observational cohort study consists of 104 patients from our center with histologically confirmed HNSCC. All patients received chemoradiotherapy (CRT) and underwent 18F-FDG-PET/CT (n = 52) or 18F-FDG-PET/MRI (n = 52) scan 12 weeks after the end of treatment. Image analysis was performed by two independent readers according to a five-point Likert scale analysis. Results. PET/MRI was more sensitive (1.00 vs. 0.77) than PET/CT in the detection of locoregional recurrence. PET/MRI also had better negative (1.00 vs. 0.87) predictive values. AUCs for PET/MRI and PET/CT on patient-based analysis were 0.997 (95% CI 0.989–1.000) and 0.890 (95% CI 0.806–0.974), respectively. The comparison of sensitivity, AUCs, and negative predictive values revealed a statistically significant difference, p < 0.05 . In PET/CT, false-negative and positive findings were observed in the more advanced disease stages, where PET/MRI performed better. Also, false-negative findings were located in the oropharyngeal, laryngeal, and nasopharyngeal regions, where PET/MRI made no false-negative interpretations. Conclusion. Based on these results, PET/MRI might be considered the modality of choice in detecting locoregional recurrence in HNSCC patients, especially in the more advanced stages in the oral cavity, larynx, or nasopharynx.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

“…In a retrospective study conducted on 23 patients with ACC, 18 F-FDG PET/CT added significant information to MRI and CT, detecting ACC primary sites with 87% sensitivity and upstaging 19% of patients compared to conventional imaging [176]. In another study of 36 patients with ACC, the addition or combination of 18 F-FDG-PET/CT to MRI improved the detection of local tumors and metastatic spread and was found to be beneficial in restaging [177]. 18 F-FDG PET/CT has higher sensitivity and diagnostic accuracy as compared to MRI for staging loco-regional tumor extension [177].…”

“…In another study of 36 patients with ACC, the addition or combination of 18 F-FDG-PET/CT to MRI improved the detection of local tumors and metastatic spread and was found to be beneficial in restaging [177]. 18 F-FDG PET/CT has higher sensitivity and diagnostic accuracy as compared to MRI for staging loco-regional tumor extension [177]. In one study, the sensitivity, specificity, and accuracy of detection of local tumors on 18 F-FDG PET/CT versus MRI were reported at 96% versus 89%, 89% versus 89%, and 94% versus 89%, respectively [176].…”

“…Moreover, another case report has shown the utility of 68 Ga-DOTATATE PET/CT for the accurate staging of ONB in the sphenoclival region. 68 Ga-DOTATATE PET/CT along with 177 Lu-DOTATATE have been used in identifying SSTR-expressing ONB patients [231,232]. 68 Ga-DOTATATE PET/CT has shown usefulness in the identification of residual tumors after resection and lesions in areas, including brain parenchyma, that did not show abnormal radiotracer uptake on 18 F-FDG PET/CT scans.…”

“…Sparse but intriguing data from case reports and a cohort study report successful administration of peptide receptor radionuclide therapy (PRRT) in patients with ONB [232,235]. 68 Ga-DOTATATE PET/CT has been used to identify SSTR-expressing ONB patients for 177 Lu-DOTATATE therapy [231,232]. Hasan et al [232] reported a cohort of seven patients undergoing 177 Lu-DOTATATE in unresectable recurrent or metastastic ONB and showed clinical and imaging responses in most patients.…”

A head-to-head comparison of 2-[18F]FDG PET/CT and 2-[18F]FDG PET/MR in patients with nasopharyngeal carcinoma under different disease settings

“…Queiroz et al compared cePET/MR with cePET/CT in 87 patients with suspected recurrence of head and neck cancer and suggested that cePET/MR may be better at specifying possible tumor recurrence with obscure FDG uptake than cePET/CT(28). PET/MR has been recommended as an alternative modality to PET/CT in postchemoradiotherapy evaluation(29).Apart from tumor recurrence, distant metastasis is the primary cause of death in NPC. Zhou et al reported that the diagnostic performance of PET/MR is superior to that of PET/CT in detecting liver metastasis…”