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- (A) Squamous cell carcinoma and adenocarcinoma are the two
most common histological types of esophageal cancers [ 9 ].
The etiology, geographic/ethic distribution, pathogenesis,
and biological behavior of them are different. It is not surpris-
ing that the prognosis of patients with these two types of
esophageal cancers is actually different even they presented
with the same stage. In the two most recent editions of the
Staging Manual, there is separate staging for esophageal squa-
mous cell carcinoma and adenocarcinoma.
(B) Patients having esophageal cancer with some histologi-
cal types having glandular differentiation could use the prog-
nostic staging group for esophageal adenocarcinoma. These
cancer types comprise adenoid cystic carcinoma, mucoepider-
moid carcinoma, mixed neuroendocrine carcinoma as well as
undifferentiated carcinoma with adenocarcinoma component.
It is worth noting that patients with esophageal adenosqua-
mous carcinoma adopt the prognostic staging group of esoph-
ageal squamous cell carcinoma. - The splitting of the prognostic staging for three groups in dif-
ferent phases of patients with esophageal adenocarcinoma is
based on the survival data obtained from WECC. It is worth
noting that in clinical staging and pathological stage, the crite-
ria for esophageal squamous cell carcinoma and adenocarci-
noma are different. For post-neoadjuvant pathological (yp)
staging, the criteria for determining the staging for esophageal
squamous cell carcinoma and adenocarcinoma are identical.
The survival of patients with post-neoadjuvant pathological
(yp) staging is less distinctive between different staging groups.
In addition, these patients have poorer survival for early stag-
ing groups when compared with corresponding group of
patients without neoadjuvant therapy. - T stage measures the extent of the carcinoma in the wall of the
esophagus and the adjacent tissue. T0 is no residual malig-
nancy detected (after neoadjuvant therapy). Tis means high-
grade glandular dysplasia of the esophagus. Starting from the
eighth edition of the AJCC Cancer Staging Manuel, T1 is sub-
divided into T1a and T1b. T1a is intramucosal adenocarci-
noma in which the carcinoma invades lamina propria or
muscularis mucosae. T1b is submucosal adenocarcinoma in
which the carcinoma invades submucosa (Fig. 1 ). T2 is adeno-
carcinoma that invades muscularis propria (Fig. 2 ). T3 is
defined when the carcinoma reaches the adventitia (Fig. 3 ). T4
is adenocarcinoma that invades structure adjacent to the
esophagus. The documentation of T4 needs clinical or radio-
logical findings. Ongoing from the seventh edition, T4 has
two subgroups: T4a and T4b. T4a is generally resectable
tumor invading the pleura, pericardium, azygous vein or dia-
phragm or peritoneum. T4b is usually unresectable tumor that
Alfred K. Lam