Field Cancerisation of the Upper Aerodigestive Tract: Screening for Second Primary Cancers of the Oesophagus in Cancer Survivors

Tobacco, alcohol, and betel quid are the main causes of squamous cell cancers of the upper aerodigestive tract. These substances can cause multifocal carcinogenesis leading to multiple synchronous or  metachronous cancers of the oesophagus, head and neck region, and lungs (‘field cancerisation’). Globally there are several million people who have survived either head and neck squamous cell cancer (HNSCC) or lung cancer (LC). HNSCC and LC survivors are at increased risk of developing second primary  malignancies, including second primary cancers of the oesophagus. The risk of second primary oesophageal squamous cell cancer (OSCC) ranges from 8-30% in HNSCC patients. LC and HNSCC survivors should be offered endoscopic surveillance of the oesophagus. Lugol chromoendoscopy is the traditional and best evaluated screening method to detect early squamous cell neoplasias of the oesophagus. More recently, narrow band imaging combined with magnifying endoscopy has been established as an alternative screening method in Asia. Low-dose chest computed tomography (CT) is the best evidencebased screening technique to detect (second primary) LC and to reduce LC-related mortality. Low-dose chest CT screening is therefore recommended in OSCC, HNSCC, and LC survivors. In addition, OSCC survivors should undergo periodic pharyngolaryngoscopy for early detection of second primary HNSCC. Secondary prevention aims at quitting smoking, betel quid chewing, and alcohol consumption. As field  cancerisation involves the oesophagus, the bronchi, and the head and neck region, the patients at risk are best surveilled and managed by an interdisciplinary team.