Detection of occult bone metastases from head and neck squamous cell carcinoma - Impact of positron emission tomography-computed tomography with fluorodeoxyglucose F 18

Objectives: To assess the ability of positron emission tomography-computed tomography with fluorodeoxyglucose F 18 (FDG-PET/CT) to provide early, accurate detection of bone metastases from head and neck squamous cell carcinoma (HNSCC) and to determine the impact of detecting occult bone metastases on patient care. Design: Retrospective medical chart review. Setting: Single academic medical center. Patients: The study population comprised 13 patients with FDG-PET/CT scans detecting bone lesions suggestive of HNSCC metastases. These patients were identified from a retrospective review of 683 consecutive FDGPET/CT scans performed for initial staging (n = 198) or restaging (n= 485) of HNSCC between October 2002 and December 2005. Main Outcome Measures: Rate of biopsy confirmation of bone lesions detected by FDG-PET/CT as suggestive of metastases, presence of concurrent symptoms or laboratory serologic evidence for bone metastasis, timing of bone metastasis detection relative to initial diagnosis of HNSCC, and change in therapeutic decision making based on bone metastasis detection. Results: Eleven FDG-PET/CT studies that detected bone metastasis were performed to restage a suspected or known recurrence, and 2 studies were performed for radiographic restaging of disease after completion of therapy. Bone biopsy confirmation was performed in 5 patients, and 4 of the biopsy results were positive for metastatic HNSCC. All patients lacked clinical symptoms of bone involvement, and 82% (n = 9) had serum alkaline phosphatase levels in the normal (n = 7) or minimally elevated (n = 2) range. At the time of bone metastasis detection, 6 of the 12 patients (50%) had no other identifiable distant metastatic disease. Furthermore, 2 patients (17%) lacked disease at any other local, regional, or distant site. The identification of bone metastases influenced therapeutic decisions in 5 of 13 cases (38%). Conclusion: Use of FDG-PET/CT in restaging HNSCC allows for detection of occult bone metastases, and this early detection frequently influences therapeutic decision making.