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.