Esophageal cancer is diagnosed by direct endoscopic visualisation and biopsy. The definitive diagnosis is made through endoscopic biopsies.
Endoscopic appearance
On endoscopy the appearance of EAC and ESCC is similar, but their location differs: most EACs sit in the distal esophagus, while most ESCCs sit in the proximal to middle portion. The tumor is not always a raised nodule; it can take several forms:
- raised nodules
- ulceration
- stricture
- depression
- subtle irregularities
Imaging that adds information
Endoscopy is the gold standard for visualising esophageal cancer, and other modalities add information. A chest radiograph (CXR) can reveal respiratory complications such as aspiration pneumonia. Barium imaging is useful when an esophageal-respiratory fistula is suspected. A CT scan can show thickening of the mucosa and a focal esophageal stricture with proximal dilation, and it can screen for the respiratory or lymph node complications of the cancer.
Improving detection of early cancer
To increase the detection rate of early-stage esophageal cancer and the precision of biopsy, conventional chromoendoscopy can be used. Stains are absorbed by normal cells but not by dysplastic or malignant cells, and this difference in absorption makes tumors stand out during endoscopic imaging. The stains used depend on the expected histology:
- potassium iodide, mostly for ESCC
- methylene blue, acetic acid or indigo carmine, mostly for glandular cancers such as EAC
Another approach, optical chromoendoscopy, uses specific light filters to distinguish normal cells from dysplastic or malignant cells. Some studies show that the use of conventional and optical chromoendoscopy increased the rate of diagnosis by 34%. Different endoscopic modalities can show the same tumor very differently: white-light high-resolution endoscopy may reveal only very subtle irregularities, while narrow-band imaging and chromoendoscopy with dyes can distinguish the tumor clearly, even showing its capillary changes.
Screening
The screening program suggested for EAC is the same as the one recommended for Barrett’s esophagus.
For screening of ESCC in high-prevalence areas, Lugol’s chromoendoscopy is used to identify the cells that do not stain. Studies show high sensitivity and specificity, above 90%, for ESCC with Lugol’s chromoendoscopy. The suggested screening schedule is:
- in underdeveloped areas with a high incidence of ESCC, once after age 50
- in countries with enough health accessibility and a high incidence of ESCC, three times after age 40, each 10 years apart
- in patients with a history of head and neck squamous cell cancers, every 6 months to 1 year after completion of cancer treatment