Squamous in the upper two-thirds, adenocarcinoma in the lower third
Mnemonic
“Squamous is upper and smoking; adenocarcinoma is lower and reflux”:
| Squamous cell | Adenocarcinoma | |
|---|---|---|
| Site | Upper and middle thirds | Lower third, gastro-oesophageal junction |
| Risk factors | Smoking, alcohol, achalasia, Plummer-Vinson, caustic stricture, hot drinks | Barrett’s oesophagus, reflux, obesity |
| Global pattern | Commonest worldwide | Rising, commonest in the West |
“Barrett’s is the bridge”: chronic acid reflux causes intestinal metaplasia of the squamous epithelium to columnar, then dysplasia, then adenocarcinoma. That sequence is why Barrett’s is surveilled endoscopically.
Presentation is late in both: progressive dysphagia, solids before liquids, with weight loss, and by then the tumour has usually breached the wall.
The oesophagus has no serosa through most of its length, only adventitia, which is why local spread happens early and why prognosis is poor.
Expansion
| Squamous cell carcinoma | Adenocarcinoma | |
|---|---|---|
| Site | Upper two-thirds | Lower third |
| Precursor | Squamous dysplasia | Barrett oesophagus |
| Risk factors | Smoking, alcohol, hot drinks, achalasia, caustic stricture, Plummer-Vinson syndrome, nitrosamines | Reflux, obesity, smoking, male sex |
| Global pattern | Commoner worldwide, “oesophageal cancer belt” | Commoner in Western countries and rising |
Barrett oesophagus is intestinal metaplasia of the lower oesophageal squamous epithelium in response to acid, and it progresses through low then high grade dysplasia to adenocarcinoma. Surveillance targets dysplasia rather than metaplasia, since the annual progression rate from non-dysplastic Barrett is low.
Presentation is late in both: progressive dysphagia, initially to solids then to liquids, with weight loss. The absence of a serosa over most of the oesophagus and the rich submucosal lymphatic plexus permit early longitudinal spread, which is why prognosis remains poor.
Plummer-Vinson syndrome (iron deficiency anaemia, glossitis and an oesophageal web) is a recognised premalignant association with squamous carcinoma.