Objectives: The T stage of oral cavity and oropharyngeal squamous cell cancer lesions has a significant impact on patient treatment and overall outcome. Determining the presence and size of palpable lymph nodes also plays an important role in the complex staging of oral cancer. Oral cavity lesions and lymph nodes are often assessed by visual approximation and palpation. The focus of this study was to determine if the introduction of a measurement tool (a ruler) changes the T stage of oral cavity and oropharyngeal lesions and the N stage of lymph nodes.
Materials/methods: Various pieces of felt that represented oral cavity and oropharyngeal lesions were placed on the tongues of cadaver specimens. Several pieces of felt of different shapes were used to represent each T stage in the oral cavity and oropharyngeal tumour staging system (American Joint Committee on Cancer). Pieces of round clay, of differing sizes, were also placed in the neck of one of the cadavers once a subplatysmal flap was raised. These pieces of clay represented the various node sizes. The study participants were four head and neck surgeons, four senior residents, four junior residents, and five medical students. All subjects were asked to visually inspect the oral cavity and oropharynx of the cadaver and approximate, to the nearest 0.5 cm, the size of the lesion. The subjects were then asked to identify the lymph nodes in the same manner. Once the participants had recorded their answers, they were asked to repeat the process with the aid of a ruler and measure the same lesions and lymph node to the nearest 0.5 cm.
Results/conclusions: In staging of oral cavity and oropharyngeal cancer, the use of a ruler is necessary to increase the accuracy of tumour staging. There was a statistically significant difference in the estimated size of tumours and nodes when using a ruler. The average absolute error using visual estimation of the tumour size was 5.6 mm. When using the ruler, the error was reduced to 1.7 mm. The node size showed the same trend, with average absolute error on visual estimation being reduced from 7.4 mm to 5.2 mm.