The most common sites of metastases are local lymphatics, followed by lung metastases. Bone metastases occur in about 15% of the patients. Brain metastases are rare and are seen mainly in patients with nasopharyngeal cancer. It is also important to remember that second primaries in the aerodigestive tract are not uncommon. Depending on tobacco and alcohol history, a second cancer of the head and neck, esophagus, or lung may occur in up to 20% of patients at some time in the course of their disease, especially if they continue to smoke and drink.
Reference: Calabresi P, Schein PS (eds): Basic Principles and Clinical Management of Cancer, 2nd ed. New York, Macmillan, 1993.