Oral Tongue Cancer

Abstract

Localised cancers of the tongue are an ideal indication for brachytherapy because there is a major requirement for local control while maintaining structure and function. (8) The most common etiological factor is tobacco, which can be compounded by alcohol intake. Men are more commonly affected than women. (21) The most important prognostic factor is the extent of disease as indicated by TNM staging. (23,16) The microscopic form of tumour may also have a bearing on outcome. Exophytic tumours do better than ulcerating and infiltrating tumours. (16) As for malignant melanoma, there is a correlation between the depth of tumour penetration and the probability of lymph node involvement. (28) Radical surgery will provide acceptable cure rates in patients with tongue cancer but often at the expense of poor function; brachytherapy is therefore preferable for T1 and small T2 tumours. (21) 2 Anatomical Topography The anterior two thirds of the tongue lie in the oral cavity (mobile tongue). The posterior third (base of tongue) is in the oropharynx and the junction between the two is at the insertion of the anterior faucial pillar and the line of the circumvallate papillae. Eighty-five per cent of tumours arise on the lateral border of the oral tongue, 10 to 15% on the ventral surface and 5% or less from the dorsal surface. (21) Tumours spread through the muscle of the tongue to the floor of mouth and mandible. Lymphatic drainage is to the jugulo-digastric nodes. The submental, submandibular and upper and lower cervical nodes may also become involved. Thirty to 40% of patients may have palpable lymph nodes on presentation. Of those who are clinically node-negative, approximately 30% may harbour subclinical disease. The risk of node involvement is increased by increasing size of tumour and depth of penetration into muscle. (28) 3 Pathology