Introduction
Squamous cell carcinoma of the hypopharynx (HPSCC) accounts for approximately 3%–5% of all head and neck cancers,1and has the poorest prognosis in primary head and neck cancers due to delayed diagnosis and the high frequency of regional neck lymph node metastasis and distant metastasis. Furthermore, the prognosis of these patients is influenced by the occurrence of second primary malignancies (SPMs).2
The theory of “field cancerization,” explained by Slaughter et al3 in 1953, states that repeated exposure of carcinogens can result in the development of multiple tumors throughout the upper aerodigestive tract (UADT). In patients with HPSCC, SPMs are common, with an incidence of 10%–50%,2,4-6 and the esophagus is the most common site. In our previous report,7 16% of the patients with HPSCC developed SPMs and esophagus is the most common site of SPMs (43%). The SPMs that occurred in the non-head and neck area had poorer survival than those in the head and neck area (30% vs. 58% at 3 years, p=0.002).
In the past, esophageal squamous cell neoplasms (ESCNs) were often diagnosed late and required highly invasive treatment.8 Recently, the improvement of endoscopy technology helps with the early detection and treatment of second primary ESCNs.9 Several published studies have investigated the efficacy of endoscopy screening for patients with newly-diagnosed head and neck cancer;9,10 however, it is interesting and important to put more effort into understanding the incidence of ESCNs and to determine the risk factors for developing metachronous second primary ESCNs in patients with treated HPSCC.
The aim of our study was to evaluate the effectiveness of image-enhanced endoscopy (IEE) for the detection of ESCNs in patients with newly-diagnosed and treated HPSCC.