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adenocarcinoma. The factors that define the grades of esophageal
adenocarcinoma are also presented in the eighth edition of the
Manual. Grade 1 (well-differentiated) adenocarcinoma is an adeno-
carcinoma with >95% of tumor composed of well-formed glands.
Grade 2 (moderately differentiated) adenocarcinoma is with
50–95% of the tumor having gland formation. Any adenocarci-
noma with <50% of the tumor demonstrating glandular formation
are classified as grade 3 (poorly differentiated) adenocarcinoma
(Figs. 5 , 6 , and 7 ).
- (A) Table 1 summaries the changes in pathological staging
group from the seventh edition to eighth edition of AJCC
Manual.
(A1) Stage I cancers are divided into stage IA, stage IB, and
stage IC (in contrast to stage IA and stage 1B in the sev-
enth edition). Stage IA is limited to cancers with T1a, N0,
M0, and G1/GX. In the new edition, stage IB cancers are
Fig. 5 Well-differentiated adenocarcinoma
Fig. 6 Moderately differentiated adenocarcinoma
Pathological Staging and Esophageal Adenocarcinoma
