Distant metastases related to lip carcinomas occur very exceptionally (0.5-2%) and can be expected in cases of advanced tumors with advanced regional disease. Distant metastases from oral cavity carcinomas variy over a broad interval (8-17%) and depend also on the stage of disease.
The knowledge of the presence of distant metastases is vital for the planning of further treatment. From a clinical point of view, patients with lip and oral cavity can be divided into a group where the risk of distant metastases is low, and into a high-risk one.
In low-risk group patients (stages I, II and III) the risk of the incidence of distant metastases is 3%, and the diagnostic approach should consist of an X-ray of the lungs and liver tests. Further examinations are necessary if there are symptoms suggesting the presence of distant metastases or previous examinations are abnormal.
The high-risk group (stage IV) and all patients with locoregional relapse have a risk of distant metastases of approximately 10% and the best treatment consists of a positron emission tomography (PET) scan. If a PET scanner is not available it is recommended to run a computed tomography scan of the lungs and liver tests.
If any clinical investigation is abnormal further tests are necessary.