Esophageal Cancer - Staging

Esophageal cancer patients tend to have locally advanced at time of presentation as there is no serosa covering the esophagus to act as a physical barrier. Intramural lymphatics allow for early access and spread of tumor to lymphatics even in tumors invading the lamina propria (T1a) or the submucosa (T1b) .

Squamous cell and adenocarcinoma are the two most common histologies in esophageal cancer. Adenocarcinomas represent 75% and SCCs represent ~25% of all esophageal cancers. SCC carries a worse prognosis. The risk factors are different for each entity.

Squamous cell carcinoma risk factors include: smoking, alcohol use, Achalasia (esophageal motility disorder), tylosis (hyperkeratinization of palms and soles), prior thoracic irradiation, prior head and neck cancer, and Plummer-Vinson syndrome (iron-deficiency anemia, glossitis, esophageal webs).

Adenocarcinoma risk factors include: smoking, gastric reflux, Barrett's esophagus, prior thoracic irradiation.

Other rare histologies include: lymphoma, sarcoma (leimyosarcomas most common), melanoma, neuroendocrine (small cell), adenoid cystic, mucoepidermoid carcinoma

Initial presenting symptoms are invariably dysphagia and weight loss. Other symptoms include cough, odynophagia and hemoptysis. Voice hoarseness suggests likely involvement of the left recurrent laryngeal nerve.

Initial work-up after full history and physical include:

• CBC, LFTs, SMA7, albumin, protein, Alk phos
  
• Endoscopic ultrasound + biopsy
• Panendoscopy
• CT chest and abdo
  
• PET scan is better than CT for assessing nodes and mets (Sensitivity ~90%)
• Barium swallow
• PFTs pre-RT

Anatomy
The Cervical Esophagus is found 15 to 20 cm from the incisors it is bounded by the hypopharynx and the sternal notch. The Upper Thoracic Esophagus is found from 20 - 25 cm bounded by the sternal notch and the Azygous vein. The Middle Thoracic Esophagus is at 25 - 30 cm bounded by the Azygous Vein and the Pulmonary Arteries. The Lower Thoracic Esophagus is at 30 - 40 cm bounded by the Pulmonary Arteries and the GE Junction.


TNM Staging
T1a = lamina propria
T1b = submucosa invasion
T2 = invades muscularis propria
T3 = invades advetitia (no serosa)
T4a = Resectable tumor invading pleura, pericardium, diaphragm
T4b = Unresectable tumor invading adjacent structures (ie trachea, aorta, vertebra)

N1 = 1-2 regional LN
N2 = 3-6 regional LN
N3 = > 6 regional LN

AJCC Staging (The 2009 7th ed AJCC stages SCC and Adenoca's differently and adds Grade and location as criteria.... really annoying)

SCC incorporates both grade and location (for stage I & II)
Stage IA: T1N0 G1
Stage IB: T1N0 G2-3; T2-3N0 G1 L
Stage IIA: T2-3N0 G2-3 L; T2-3N0 G1 U/M
Stage IIB: T2-3N0 G2-3 U/M; T1-2N1
Stage IIIA: T3N1; T4aN0; T1-2N2
Stage IIIB: T3N2
Stage IIIC: T4aN1-2; T4bNx; TxN3
Stage IV: TxNxM1

Adenocarcinomas only use grade for Stage I & II
Stage IA: T1N0 G1-2
Stage IB: T1N0 G3; T2N0 G1-2
Stage IIA: T2N0 G3
Stage IIB: T3N0; T1-2N1
Stage IIIA: T3N1; T1-2N2; T4aN0
Stage IIIB: T3N2
Stage IIIC: T4aN1-2; T4bNx; TxN3
Stage IV: TxNxM1

Justifications for using such a complicated staging system.... data analysis demonstrates that prognosis is affected by grade, location, and histological cancer type.

5-year OS
Stage I: 50-60%
Stage II: 40%
Stage III: 20%
Stage IV: <5%

Prognosis is the same between SCC and Adenocarcinoma because of the changes to the TNM staging system. This wasn't the case before the change.