Introduction
Synchronous malignancies occurring along the upper aerodigestive tract was originally discovered by Billroth1 and Slaughter2, with the latter proposing the theory of ‘field cancerization’. The theory of ‘field cancerization’ suggested that with exposure to tobacco and alcohol, synchronous multifocal malignancies can occur in oesophagus and lung for patients with primary head and neck squamous cell carcinomas (HNSCCs). The rate of occurrence of such synchronousmalignancies can be as high as 23%3-6 and their overall survival can be 50% worse when compared with first primaries. Oesophagoscopy and bronchoscopy had beenthe procedure of choice for screening synchronous malignancies along the upper aerodigestive tract7-9. Debates however existed on whether the routine use of them were warranted as there were concerns over risks and cost of procedure and increasing waiting time before start of treatment10-13. The aim of this study is therefore to find out the rate of such synchronousmalignancies in patients with primary HNSCCs, the risk factors for its occurrence and the effectiveness of oesophagoscopy and bronchoscopy in a single center with Chinese population.