G07 - Role of PET/TC in the pre-surgery staging of oral cavity cancers

Abstract

Background: Among head and neck cancers oral cavity squamous cell carcinomas (OCSCC) account for about one third of the cases. Traditionally the pre-surgical staging has been based on lymph nodes evaluation by means of Computed Tomography (CT). The superiority of Positron Emission Tomography (PET)/CT in detecting regional nodal involvement has been claimed by some studies recently published. The aim of this study was to evaluate the impact of PET/CT imaging on nodal staging of patients undergoing surgery for OCSCC and to compare PET/CT with CT in this specific setting. Patients and methods: A retrospective analysis has been conducted on a data-base registry from a single institution. The study population consisted of 50 patients affected by OCSSC who were evaluated with both PET/CT and CT before undergoing surgery on the primary tumor and neck dissection. The study population consisted of 29 males and 21 females, median age was 63 years, the most common involved siites were the retromolar trigonus and the gingival fornyx (34%) and the mobile tongue (28%). After neck dissection (selective or radical, 34% bilateral) the pathologic specimens were thoroughly reviewed by an experienced pathologist. Twenty-nine cases (58%) were classified as T4 and 28 (56%) as N0. Results: Neck dissection resulted in the presence of lymph node metastases in 44% of the patients. PET/CT detected true positive nodes in 20 of 22, and true negative nodes in 21 of 28 specimens while CT detected true positive nodes in 16 of 17 and true negative nodes in 18 of 23 specimens. Sensitivity and specificity of PET/TC were 91% and 75% respectively with an accuracy rate of 82%; sensitivity and specificity of CT were 94% and 78% respectively with an accuracy rate of 85%. Both figures are comparable with previously published data. No significant statistical differences were found between PET/CT and CT (p = 0.823). Conclusions: In our study PET/CT was an effective tool to assess the nodal stage of OCSCC, but did not prove to be more accurate than CT. While its role in detecting unknown primaries and distant metastases is well consolidated, further randomized trials will help in claryfing its real usefulness in loco-regional disease. According to our data some patients could be overstaged, nonetheless the fear of overtreatment with neck dissection is counterbalanced by the effective prophylactic role of the procedure.