Cognitive impairment causes a delay in diagnosis and treatment of the various cancer entities, resulting in reduced surgical outcomes and patient survival. However, no investigations have been carried out as to whether an association exists between cognitive functioning and tumour size in patients with oral squamous cell carcinoma (OSCC). In this study, 46 patients with OSCC were evaluated by using a screening test for dementia, consisting of a combination of the mini-mental state examination and the clock test (81% sensitivity and 90% specificity). Test scores were correlated with tumour size according to the TNM staging system, which was categorized as being either limited (T1, T2; n=24) or advanced (T3, T4; n=22). No difference in age (P=0.172), sex (P=0.330), the percentage of drinkers (P=0.090) or the percentage of smokers (P=0.484) was evident between the groups. Patients with advanced tumour size scored significantly lower (median 5.5 of 9 possible points) when compared with those having tumours of a limited size (median 9 of 9 possible points; P=0.005). The median score of patients with T3/T4 tumours suggested the need for comprehensive neuropsychological evaluations for dementia. In conclusion, this study has demonstrated the correlation of reduced cognitive functioning in patients with advanced OSCC. As a consequence, instructions for the identification of early signs and of symptoms of oral cancer are strongly recommended for relatives and nursing staff of patients with cognitive impairment. Such patients might need immediate treatment for oral cancer but might not be able to understand the significance of their symptoms and therefore present late, often too late.
