Oesophageal Carcinoma

Description

Oesophageal carcinoma is a malignant tumour that originates in the epithelial lining of the oesophagus. It is the seventh most common malignancy globally and the sixth most common cause of cancer-related deaths worldwide. The primary types of oesophageal cancer are squamous cell carcinoma, more common in lower and middle-income countries, and adenocarcinoma, more frequent in higher-income nations. The most common presenting symptom is dysphagia, often associated with weight loss.

Pathogenesis

The precise pathogenesis of oesophageal carcinoma is multifactorial and varies by subtype. It typically involves genetic mutations that accumulate over time, driven by various risk factors. In adenocarcinoma, gastric acid reflux, leading to Barrett’s oesophagus, is a major risk factor. Squamous cell carcinoma often associates with smoking and excessive alcohol use.

Subtypes

• Squamous cell carcinoma (SCC): Most common. Arises from the squamous epithelial cells that line the oesophagus. Typically located in the upper and middle parts. Can be associated with Plummer-Vinson Syndrome.
• Adenocarcinoma (AC): Arises from the glandular cells located at the gastroesophageal junction or distal oesophagus. Often associated with Barrett’s oesophagus.

Epidemiology, Risk Factors & Associations

• Most common in individuals aged 55 and older

Risk factors include:

• Smoking (risk increases with the duration and number of cigarettes smoked)
• Alcohol consumption (especially for SCC)
• Gastro-oesophageal reflux disease (GORD) and Barrett’s oesophagus (especially for AC)
• Achalasia of the stomach cardia (increases risk by 30x)
• Obesity (BMI > 30 increases risk of AC, likely due to associated with GORD)
• Dietary factors – poor nutrition and low fruit and vegetable intake. Food rich in nitrates and nitrosamines.
• Plummer–Vinson syndrome (iron deficiency anaemia and oesophageal webs) – associated with proximal oesophageal squamous cell carcinoma (as with oropharyngeal and laryngeal SCC).

Clinical Features

• Progressive dysphagia (initially with solids, then progressing to liquids)
• Weight loss
• Retrosternal pain or discomfort
• Hoarseness and cough, if recurrent laryngeal nerves are involved
• Possible signs of metastatic disease depending on the site (e.g., liver, lungs, bone)

Complications

• Oesophageal obstruction
• Tracheo-oesophageal fistula
• Metastatic spread, most commonly to liver, lungs, and bone
• Nutritional deficiencies due to swallowing difficulties

Pathological Features

Histopathology

• Macroscopic: Typically a polypoidal or fungating mass in the oesophageal lumen. May also be sessile, pedunculated, lobulated or apple-core lesion. Advanced cases can lead to luminal narrowing.
• Microscopic: Squamous cell carcinomas are composed of atypical squamous cells, often forming keratin pearls. Adenocarcinomas show glandular architecture with dysplasia of columnar epithelium.

Serology

• Anaemia could be present due to chronic bleeding from the tumour.

Biochemistry

• Alkaline phosphatase and liver function tests may be altered in case of liver metastases.

Radiological Features

General Features

• Characteristically demonstrates an irregular luminal narrowing or mass, which can be concentric (“apple-core”) or eccentric. Mucosal irregularity and shouldering are typical. There may be associated proximal oesophageal dilatation.
• Morphologies
  • Infiltrative, shelf-like margins
  • Annular, constricting
  • Polypoidal
  • Ulcerative
  • Varicoid
  • Bulky
• May invade into mediastinum and aorta
• Local lymph node enlargement
• Metastases to liver, lung, lymph node and gastrohepatic ligament

CT

• Non-contrast: Demonstrates wall thickening or an oesophageal mass.
• Contrast-enhanced: Enhancing oesophageal wall thickening or mass, often with an irregular lumen.

MRI

• T1WI: The tumour is generally hypointense relative to normal oesophageal wall.
• T2WI: Typically hyperintense relative to the oesophageal wall.
• T1 C+: Shows enhancement after contrast administration.
• DWI/ADC: Restriction of diffusion may be seen.

PET FDG

• Typically shows high FDG uptake within the primary tumour and any metastatic lymph nodes or distant metastases.

Fluoroscopy (Barium Swallow)

• Shows irregular narrowing of the lumen (“rat tail” or “apple core” sign) and mucosal irregularity.

Grading and Staging

The TNM (Tumour, Node, Metastasis) staging system is used. Detailed criteria depends on the cancer subtype (adenocarcinoma or squamous cell carcinoma).

Diagnosis

The definitive diagnosis is made by endoscopic biopsy of the tumour, confirming malignancy on histopathological analysis. Radiological studies provide information on the extent of the disease.

Differential Diagnosis

• Benign oesophageal stricture (typically has smooth tapered narrowing)
• Leiomyoma (usually well-defined, homogeneously hypoechoic on EUS)
• Leiomyosarcoma
• Lymphoma – Usually secondary metastatic disease. Primary is rare (oesophagus/stomach lacks lymphocytes). Usually infiltrative, ulcerating, polyploid or endoexophytic.
• Caustic ingestion
• Gastro-oesophageal reflux disease (GORD)
• Achalasia (bird beak sign but without a mass lesion)

Management

Treatment depends on the stage of the disease and includes a combination of surgery, radiation therapy, and chemotherapy. For local disease, oesophagectomy is typically performed. Neo-adjuvant chemo-radiotherapy may be used in locally advanced disease. Palliative measures such as stenting may be utilised in advanced/metastatic disease or in those unfit for surgery.