18F-fluorodeoxyglucose dual-head positron emission tomography as a procedure for detecting simultaneous primary tumors in cases of head and neck cancer

Abstract

Second primary tumors are a leading cause of death among patients with head and neck cancer; therefore, early detection of these tumors is necessary. In the current study, the authors aimed to evaluate the diagnostic capacity of (18)F-fluorodeoxyglucose dual-head positron emission tomography (FDG-PET) for detecting second primary tumors in patients presenting with primary head and neck cancer. The authors prospectively studied a case series of 68 consecutive patients with a primary tumor in the oral cavity or oropharynx. Within a period of 3 weeks, clinical examination, chest X-ray, computed tomography, and ultrasonography of the head and neck were performed on all patients. Irrespective of the results, patients underwent FDG-PET of the head, neck, and chest. Due to its low yield in the detection of second primary tumors, panendoscopy was not used in this study. All patients were followed up for at least 6 months to assess the number of simultaneous and synchronous tumors missed by FDG-PET. In 12 of 68 patients (18%; 95% confidence interval [CI]: 8-28%), a second simultaneous primary malignant tumor was found by FDG-PET. Five of these tumors (7%; 95% CI: 1-13%) were also detected by clinical or radiologic examination (P = 0.016). With one exception, all tumors were found in the epithelium of the upper digestive and respiratory tract. However, even when the patient with a second primary tumor in the thyroid was excluded from evaluation, FDG-PET significantly improved the detection rate of second primaries (P = 0.031). In none of the 68 patients studied were additional simultaneous or synchronous primary tumors found during follow-up. The use of FDG-PET significantly increases the rate of detection of simultaneous second primary tumors. The results of our study suggest that most of the second primary tumors are detected in an early stage.