Pathology and pathobiology of the oesophageal carcinoma

Carcinoma of the oesophagus including carcinoma of gastro-oesophageal junction are rapidly increasing in incidence. During recent years there have been changes in the knowledge surrounding biology of the disease progression. Identification of dysplasia in mucosal biopsies is the most reliable pathologic indicator of an increased risk of development of squamous cell carcinoma and passes through the sequence of chronic esophagitis, low-grade and high-grade dysplasia and invasive carcinoma. Although Barrett's esophagus is a precursor to esophageal adenocarcinoma and have a well described sequence of carcinogenesis: the Barrett's metaplasia-dysplasia-adenocarcinoma sequence, not all patients with this disorder require intensive surveillance. The natural history of dysplasia is poorly understood, particularly in low-risk regions, and prospective follow-up studies are needed. Adjunctive methods to improve reproducibility, such as immunostaining for alpha-methylacyl-coenzyme A racemase (AMACR), show promise, but require confirmation in larger studies. In addition, several controversial methods such as detection of p16, p53, and DNA content abnormalities may help identify patients at particularly high risk for progression to cancer, but these techniques are not yet widely available for routine clinical application. More studies are needed to define other early nonmorphologic biomarkers for risk of squamous cell carcinoma. Recent evidence regarding the importance of several histopathologically derived prognostic factors, such as circumferential resection margin status and lymph node metastases are evaluated, including lymph node micrometastases and the sentinel node concept. With the rising use of multimodal treatments for oesophageal cancer it is important that the response of the tumour to this therapy can be carefully documented by histopathology.