TNM Classification for Esophageal Cancer
The American Joint Committee on Cancer (AJCC) tumor/node/metastasis (TNM) classification system for esophageal and esophagogastric junction cancer is provided below, along with histologic grade and anatomic/prognostic groups for squamous cell carcinoma and adenocarcinoma. [1, 2]
T/N staging
The T indicator is related to the extent of tumor invasion. The T stage (Table 1) has a direct impact on the patient’s stage, the likelihood of metastatic nodal disease, and outcome. [3] The location of the primary tumor does not have a direct correlation with prognosis, but influences management decisions, especially for non-metastatic disease, including surgical planning, consideration of neoadjuvant therapy, and determining radiation fields.
Positron emission tomography–computed tomography (PET-CT) has limited use in the T staging of esophageal cancers; however, it can demonstrate signs of adjacent organ infiltration. Endoscopic ultrasonography (EUS) is the imaging modality of choice for the evaluation of T staging. [4] Advanced (T4) disease is more accurately identified than early (T1) disease [5] ; differentiating Tis, T1a, and T1b disease can be challenging. [6]
EUS can also be used to evaluate regional lymph nodes, allowing for N staging, especially with use of fine needle aspiration (FNA). CT and PET are inadequate for staging celiac and mediastinal lymph nodes. [7, 8, 9, 10] However, CT and EUS together can increase the accuracy of regional lymph node evaluation. [7, 11]
For T and N staging, EUS has good sensitivity and specificity. [5, 7]
M staging
PET-CT is extremely useful for the detection of metastatic disease that may not be identifiable with other imaging modalities. Diagnostic-quality CT images are also useful for additional information in case of uncertainties in the PET images. Fused images are also extremely useful, again, in the localization of subtle metastases and also for guiding a potential percutaneous biopsy.
PET-CT is the gold standard for evaluation of treatment with regard to quantifying metastatic disease response. This becomes particularly important as metabolic response to chemotherapy can often outstrip physical change in the tumor. Metabolic response has been seen to correlate with the histopathologic response, and the 3-year survival is far better in responders than in nonresponders (70% vs. 35%, respectively, in a study of esophageal junction adenocarcinoma). [12]
Pathologic staging
Histopathologic staging after surgical or endoscopic resection (Table 5) and postneoadjuvant therapy (Table 6) can be used for prognostication and guiding further management. [13]
Table 1. TNM Classification (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence of primary tumor |
Tis |
High-grade dysplasia,* defined as malignant cells confined by the basement membrane |
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, azygos vein, diaphragm, or peritoneum |
T4b |
Unresectable tumor invading other adjacent structures, such as the aorta, vertebral body, and trachea |
*High-grade dysplasia includes all noninvasive neoplastic epithelial lesions formerly called carcinoma in situ; that term is no longer used for columnar mucosae anywhere in the gastrointestinal tract. |
|
Regional lymph nodes (N) |
|
NX |
Regional lymph node(s) cannot be assessed |
N0 |
No regional lymph node metastasis |
N1 |
Metastasis in 1-2 regional lymph nodes |
N2 |
Metastasis in 3-6 regional lymph nodes |
N3 |
Metastasis in 7 or more regional lymph nodes |
Distant metastasis (M) |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
Table 2. Histologic grade (Open Table in a new window)
Histologic grade (G) |
|
GX |
Grade cannot be assessed—stage grouping as G1 |
G1 |
Well differentiated |
G2 |
Moderately differentiated |
G3 |
Poorly differentiated or undifferentiated* |
*If undifferentiated with glandular component, stage as G3 adenocarcinoma; if undifferentiated with squamous cell component, or tumor remains undifferentiated after further testing, group as G3 squamous cell carcinoma. |
Table 3. Squamous cell carcinoma location (Open Table in a new window)
X |
Location unknown |
Upper |
Cervical esophagus to lower border of azygos vein |
Middle |
Lower border of azygos vein to lower border of inferior pulmonary vein |
Lower |
Lower border of inferior pulmonary vein to stomach, including gastroesophageal junction |
Table 4. Clinical stage groups (Open Table in a new window)
Stage Group |
cT |
cN |
cM |
---|---|---|---|
Squamous cell carcinoma |
|||
0 |
Tis |
N0 |
M0 |
I |
T1 |
N0–1 |
M0 |
II |
T2 |
N0–1 |
M0 |
T3 |
N0 |
M0 |
|
III |
T3 |
N1 |
M0 |
T1–3 |
N2 |
M0 |
|
IVA |
T4 |
N0–2 |
M0 |
T1–4 |
N3 |
M0 |
|
IVB |
T1–4 |
N0–3 |
M1 |
Adenocarcinoma |
|||
0 |
Tis |
N0 |
M0 |
I |
T1 |
N0 |
M0 |
IIA |
T1 |
N1 |
M0 |
IIB |
T2 |
N0 |
M0 |
III |
T2 |
N1 |
M0 |
T3–4a |
N0–1 |
M0 |
|
IVA |
T1–4a |
N2 |
M0 |
T4b |
N0–2 |
M0 |
|
T1–4 |
N3 |
M0 |
|
IVB |
T1–4 |
N0–3 |
M1 |
Table 5. Pathologic stage groups (Open Table in a new window)
Stage group |
pT |
pN |
pM |
Grade |
Location |
---|---|---|---|---|---|
Squamous cell carcinoma |
|||||
0 |
Tis |
N0 |
M0 |
N/A |
Any |
IA |
T1a |
N0 |
M0 |
G1, X |
Any |
IB |
T1b |
N0 |
M0 |
G1–3, X |
Any |
T1a |
N0 |
M0 |
G2–3 |
Any |
|
T2 |
N0 |
M0 |
G1 |
Any |
|
IIA |
T2 |
N0 |
M0 |
G2–3, X |
Any |
T3 |
N0 |
M0 |
Any |
Lower |
|
T3 |
N0 |
M0 |
G1 |
Upper/middle |
|
IIB |
T3 |
N0 |
M0 |
G2–3 |
Upper/middle |
T3 |
N0 |
M0 |
GX |
Any |
|
T3 |
N0 |
M0 |
Any |
X |
|
T1 |
N1 |
M0 |
Any |
Any |
|
IIIA |
T1 |
N2 |
M0 |
Any |
Any |
T2 |
N1 |
M0 |
Any |
Any |
|
IIIB |
T4a |
N0–1 |
M0 |
Any |
Any |
T3 |
N1 |
M0 |
Any |
Any |
|
T2–3 |
N2 |
M0 |
Any |
Any |
|
IVA |
T4a |
N2 |
M0 |
Any |
Any |
T4b |
N0–2 |
M0 |
Any |
Any |
|
T1–4 |
N3 |
M0 |
Any |
Any |
|
IVB |
T1–4 |
N0–3 |
M1 |
Any |
Any |
Adenocarcinoma |
|||||
0 |
Tis |
N0 |
M0 |
N/A |
|
IA |
T1a |
N0 |
M0 |
G1, X |
|
IB |
T1a |
N0 |
M0 |
G2 |
|
T1b |
N0 |
M0 |
G1–2, X |
||
IC |
T1 |
N0 |
M0 |
G3 |
|
T2 |
N0 |
M0 |
G1–2 |
||
IIA |
T2 |
N0 |
M0 |
G3, X |
|
IIB |
T1 |
N1 |
M0 |
Any |
|
T3 |
N0 |
M0 |
Any |
||
IIIA |
T1 |
N2 |
M0 |
Any |
|
T2 |
N1 |
M0 |
Any |
||
IIIB |
T4a |
N0–1 |
M0 |
Any |
|
T3 |
N1 |
M0 |
Any |
||
T2–3 |
N2 |
M0 |
Any |
||
IVA |
T4a |
N2 |
M0 |
Any |
|
T4b |
N0–2 |
M0 |
Any |
||
T1–4 |
N3 |
M0 |
Any |
||
T1–4 |
N0–3 |
M1 |
Any |
||
N/A = not applicable; X = not defined |
Table 6. Post-neoadjuvant therapy staging (Open Table in a new window)
Stage Group |
ypT |
ypN |
ypM |
---|---|---|---|
I |
T0-2 |
N0 |
M0 |
II |
T3 |
N0 |
M0 |
IIIA |
T0-2 |
N1 |
M0 |
IIIB |
T4a |
N0 |
M0 |
T3 |
N1 |
M0 |
|
T0-3 |
N2 |
M0 |
|
IVA |
T4a |
N1-2, X |
M0 |
T4b |
N0-2 |
M0 |
|
T1-4 |
N3 |
M0 |
|
IVB |
T1–4 |
N0–3 |
M1 |