Discussion
The occurrence of SPMs is a crucial issue in the treatment of HPSCC.
Previous observations have shown that the frequency of SPMs vary from
7-36%, according to the anatomical site of original primary. In
particular, second primary ESCNs are more frequently found in patients
with HPSCC. This phenomenon is supported by the concept of field
carcinogenesis.4-6,9,15-18The average prevalence of
second primary ESCNs in patients with HPSCC in a recent systemic review
was 15.2% (413 of 3386, 95% CI: 11.4-19.0).19 In
terms of sublocation, the average prevalence of esophageal lesions
screened both synchronously and metachronously in patients with
hypopharyngeal tumors of seven studies was 28.0% (161 of 574, 95% CI:
22.5-33.5).
Our study analyzed 99 patients with HPSCC who received IEE screening of
the upper gastrointestinal tract. We used the triple endoscopy
combination of conventional white-light endoscopy (WLE), narrow-band
imaging with magnification (NBI-M) and Lugol chromoendoscopy to detect
suspicious ESCNs. The prevalence of second primary ESCNs in the ND group
was 27%, and 33% in the FU group. Our results were similar to those
obtained studies and represented that relatively high chance of
synchronous and metachronous esophageal malignancies could be detected
through IEE compared with traditional white light endoscopy.20
In the ND group, 8 of the 30 patients (27%) was found second primary
ESCNs in the IEE screening with varies histology, including severe
dysplasia, carcinoma in situ, and SCC. It is essential to evaluate the
UADT before definitive treatments and may change the treatment
planning.18
SPMs have a significant effect on the survival of patients with primary
head and neck cancers, and are a major threat to the morbidity and
mortality of patients with HPSCC after treatment. Second primary
esophageal cancer, especially, is known to be associated with a poor
prognosis.21,22 Patients with second primary ESCNs
have significantly lower survival rates (HR 2.75/2.79, 95% CI
1.11~6.82/1.15~6.80, p =
0.03/0.02 in multivariate analyses) than those without second primary
ESCNs.23
In the FU group, 23 of the 69 patients (33%) had second primary ESCNs
in the IEE examination. According to previous
studies,24,25 the risk analysis of clinical parameters
revealed that alcohol exposure and N3 disease of HPSCC were the most
important independent risk predictors for simultaneous esophageal
lesions. Some studies showed that an age of under 50 years was also a
risk predictor on univariate analysis as well.26,27Our study shows only those with previous history of SPMs-UADT had higher
incidence of second primary ESCN than those without the history (35%
vs. 13%, p =0.0343). Therefore, routine IEE screening of the
esophagus is recommended for HPSCC patients, especially at those with
previous history of SPMs in the UADT.
Most oncologists agree that early diagnosis and treatment are the best
way to manage SPMs in head and neck cancer. Imaged-enhanced endoscopy
has become a useful screening tool for precancerous or early cancerous
lesions in the esophagus by means of dye- or optical-based
techniques.28 When using the combination of
chromoendoscopy with Lugol solution and NBI system with high-resolution
ME, the margin and invasiveness of the neoplasia can be well delineated
and predicted.28-30
More and more researchers have suggested that routine screening of ESCNs
in patients with head and neck cancer is recommended. In clinical
practice, however, a comprehensive UGI endoscopy may not be possible in
treated HPSCC patients because of local tumor obstruction or structural
changes after surgery or irradiation. It is important to find out the
characteristics of high-risk second primary ESCNs occurrence groups for
more detailed surveillance arrangement. Also, it is also important to
know the role of endoscopy in patients without dysphagia or other GI
symptoms. In our study of the FU group, there was significant difference
in clinical T-classification and treatment modalities of ESCNs between
patients with symptoms and those without symptoms; patients without
symptoms at the time of UGI screening had less advanced T stages (44%
vs. 0%, p = 0.0359), and had a higher percentage of non-minimal
invasive therapy (75% vs. 0%, p = 0.0013).