PET‐CT for Detecting Nodal Metastasis in cN0 Early‐Stage Oral Cavity Squamous Cell Carcinoma

Objectives: To determine if positron emission tomography (PET)‐computed tomography (CT) offers any diagnostic advantage over traditional CT neck in assessing the clinically N0 neck in patients with T1 and T2 squamous cell carcinoma (SCC) of the oral cavity. Methods: We performed a retrospective review of patients in the Alberta Cancer Registry who were diagnosed with cT1 or T2N0M0 disease who underwent elective unilateral or bilateral neck dissections. Results of preoperative PET‐CT and CT necks were reviewed for number of “suspicious” lymph nodes. Surgical pathology reports were reviewed to obtain the total number of nodes sampled and number of malignant nodes. Results: Between 2009 and 2011, 148 patients were diagnosed with cT1 or T2N0M0 SCC of the oral cavity. Of these, 62 patients underwent elective neck dissections. Fourteen patients underwent preoperative PET‐CT while 48 patients underwent CT neck alone. Based on final surgical pathology, 6 nodes out of 499 nodes sampled were falsely fludeoxyglucose‐avid in the PET‐CT group while 3 nodes out of 1800 were falsely identified as suspicious on CT neck alone. The overall false positive rate of PET‐CT was significantly higher than CT alone (1.2% vs 0.2%, P <. 001). Both modalities had excellent specificity of >98% for benign nodes in these patients. Conclusions: In patients with cT1 and T2 of the oral cavity and no palpable lymphadenopathy, PET‐CT is no better than CT alone for ruling out nodal metastasis and may have a higher false positive rate.