• What is screening?
• Screening for Colorectal Cancer
• Screening and Barrett’s oesophagus

What is screening?

Screening is the process of detecting potentially serious disease at an early stage so that effective treatment can be given before that disease becomes too advanced to treat. When applied to the field of cancer diagnosis screening works best when the disease is relatively common and a clear precancerous stage can be identified.

Colorectal cancer affects 1 in 17 people in their lifetime. The incidence rises with age. Colon polyps precede invasive cancer in many cases. Colon polyps can be seen and remover by colonoscopy. Colonoscopy is the most effective form of screening for bowel cancer and has been shown to reduce deaths from bowel cancer.

Barrett’s oesophagus predisposes to oesophageal cancer. In a population with Barrett’s oesophagus undergoing screening between 1 in 50 and 1 in 150 annual examinations are required to detect one cancer. Screening of Barrett’s oesophagus is done by gastroscopy and biopsy.

Screening and Barrett’s oesophagus

Barrett’s oesophagus or columnar lined oesophagus (CLO) occurs when severe acid reflux causes ulceration of the lining mucosa of the lower gullet (oesophagus). Normally the oesophagus is lined by skin like squamous mucosa. In Barrett’s oesophagus the lining regenerates as an acid resistant stomach type coloumnar mucosa.
Patients with Barrett’s oesophagus are at increased risk of developing oesophageal cancer. Screening is designed to pick up precancerous abnormalities (dysplasia) which can be treated before cancer becomes incurable.

The risk of cancer developing is small however, comparisons of screen detected verses symptomatic cancer showed an earlier stage (more curable) cancer in the screened detected group.

In patients where there is no dysplasia on initial biopsies a 2 year screening interval is thought to be optimal.

In patients where low grade dysplasia is found a extensive repeat biopsy is advocated after a course of strong acid suppressant (PPI) therapy over 8-12 weeks. If dysplasia is not found on repeat biopsy this should be repeated at 6 months and if still absent a 2 year interval is reverted to. If low grade dysplasia persists repeat biopsies at 6 month intervals are recommended if it remains stable.
High grade dysplasia is associated with cancer in 30-40% of cases and if confirmed by 2 expert pathologists surgical excision may be recommended.

New therapies for dysplasia are being developed which do not require oesophageal resection.

Please contact us for more information on screening.