Esophageal Cancer Staging

Fig. 6.1

7th edition TNM classifications. T is classified as Tis: high-grade dysplasia; T1 cancer invades lamina propria, muscularis mucosae, or submucosa, T2 cancer invades muscularis propria, T3 cancer invades adventitia, T4a resectable cancer invades adjacent structures such as the pleura, pericardium, or diaphragm, and T4b unresectable cancer invades other adjacent structures, such as the aorta, vertebral body, or trachea. N is classified as N0 no regional lymph node metastasis, N1 regional lymph node metastases involving 1–2 nodes, N2 regional lymph node metastases involving 3–6 nodes, and N3 regional lymph node metastases involving 7 or more nodes. M is classified as M0 no distant metastasis and M1 distant metastasis

Table 6.1

2010 7th edition AJCC/UICC TNM classifications

Primary tumor (T)
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	High-grade dysplasia^a
T1	Tumor invades lamina propria, muscularis mucosae, or submucosa
T1a	Tumor invades lamina propria or muscularis mucosae
T1b	Tumor invades submucosa
T2	Tumor invades muscularis propria
T3	Tumor invades adventitia
T4	Tumor invades adjacent structures
T4a	Resectable tumor invading pleura, pericardium, or diaphragm
T4b	Unresectable tumor invading other adjacent structures, such as the aorta, vertebral body, trachea, etc.
Regional lymph nodes (N)^b
NX	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1	Regional lymph node metastases involving 1–2 nodes
N2	Regional lymph node metastases involving 3–6 nodes
N3	Regional lymph node metastases involving 7 or more nodes
Distant metastasis (M)
M0	No distant metastasis
M1	Distant metastasis
Histopathologic type
Squamous cell carcinoma
Adenocarcinoma
Histologic grade (G)
GX	Grade cannot be assessed—stage grouping as G1
G1	Well differentiated
G2	Moderately differentiated
G3	Poorly differentiated
G4	Undifferentiated—stage grouping as G3 squamous
Location ^c
Upper or middle—cancers above lower border of inferior pulmonary vein
Lower—below inferior pulmonary vein

Notes

^aIncludes all noninvasive neoplastic epithelium that was previously called carcinoma in situ. Cancers stated to be noninvasive or in situ are classified as Tis.

^bNumber must be recorded for total number of regional nodes sampled and total number of reported nodes with metastases.

^cLocation (primary cancer site) is defined by position of upper (proximal) edge of tumor in esophagus

A regional lymph node has been redefined to include any paraesophageal lymph node extending from cervical nodes to celiac nodes (Table 6.1). Data analyses support convenient coarse groupings of the number of cancer-positive nodes (2–4). Regional lymph node (N) classification comprises N0 (no cancer-positive nodes), N1 (1 or 2), N2 (3–6), and N3 (7 or more). N classifications for cancers of the esophagus and esophagogastric junction are identical to stomach cancer N classifications.

The subclassifications M1a and M1b have been eliminated, as has MX (Table 6.1). Distant metastases are simply designated M0, no distant metastasis, and M1, distant metastasis.

7th Edition: Nonanatomic Cancer Characteristics

Nonanatomic classifications identified as important for stage grouping (Table 6.1) are histopathologic cell type, histologic grade, and tumor location (Fig. 6.2). The difference in survival between adenocarcinoma and squamous cell carcinoma is best managed by separate stage groupings for stages I and II. Increasing histologic grade is associated with incrementally decreasing survival for early-stage cancers. For adenocarcinoma, distinguishing G1 and G2 (well and moderately differentiated) from G3 (poorly differentiated) is important for stage I and stage IIA cancers. For squamous cell carcinoma, distinguishing G1 from G2 and G3 is important for stage I and II cancers. Tumor location (upper and middle thoracic versus lower thoracic) is important for grouping T2–3N0M0 squamous cell cancers.