6. Co-morbidities

Patients with oral cancer may also be prone to co-morbidities, mainly:

Cancers may arise at multiple sites – either synchronously, or later (metachronously, ie at least six months after the primary tumour). Criteria for such SPTs (Figure 1) include:

SPTs may arise because of a genetic predisposition, or from the effects of lifestyle or possibly environment. There is some evidence that SPTs can share some, or even all, genetic markers with the index tumour, indicating that both tumours have arisen from a common clonal progenitor cell. Rare patients have a genetic predisposition to develop multiple tumours because they have an inherited mutation in one allele of the tumour suppressor gene p53 locus (Li Fraumeni syndrome). Patients suffering from Fanconi anaemia, a recessively inherited disease characterized by congenital anomalies and bone marrow failure, also have a predisposition to develop cancer, particularly squamous cell carcinomas in the head and neck and anogenital regions.