NBI in Oral Cavity Cancer

Patients with primary oral cavity cancer will be examined with Narrow Band Imaging (NBI) at the time of surgery. Olympus® equipment will be used together with straight 5,9 mm endoscopes. First the tumour border seen in white light will be defined. Thereafter endoscopic examination with white light and NBI will be performed and recorded. Then the tumour border seen in white light will be marked with dots by monopolar diathermy. Finally the area is examined again with NBI and if the tumour border is seen outside the border seen in white light, that area is marked by a suture for the pathology report. Since the purpose of this study is to gain knowledge of NBI in oral cavity cancer, the resection margin will be marked at least 10mm from the tumour border as it is seen in white light in the ordinary fashion. However there are evolving evidence that NBI better delineate tumour border in larynx and some data for the oral cavity, therefore any suspected mucosa according to NBI outside the ordinary resection margin will be included with a small margin. There is no uniform definition of the NBI pattern in oral cavity cancer. The planned criteria is changed IPCL type III/IV according to Takano (see ref.) and so called "marked brown dots" as criteria for precancerous or cancerous mucosa according to NBI. The tumour border in white light and NBI will be compared and PAD is considered gold standard. To reach 80% power with 5 % type 1 error, two-sided test, and 25% of the examinations anticipated to show different tumour border with NBI, 49 participants will be needed.