Monday, December 21, 2015
Can Esophageal Cancer Be Prevented?
By: Brian A. Brunson, M.D., Gastroenterology Associates of North-Central Alabama, P.C.
Esophageal adenocarcinoma, or cancer of the lower portion of the esophagus, is one of fastest growing cancers in our country over the last several decades, with the number of new diagnoses growing six-fold from 1975-2001. It carries a poor prognosis, with a 17% five year survival once diagnosed. A condition known as Barrett’s Esophagus (BE) is the primary risk factor for the development of esophageal adenocarcinoma. Up to 1.3% of the general population is affected by BE, although this number is higher in patients seen in a typical gastroenterology practice (up to 5-10%). Barrett’s esophagus is thought to result from prolonged acid exposure in the esophagus, leading to replacement of the normal lining (squamous epithelium) with a specialized lining called intestinal metaplasia. Gastroesophageal reflux disease (GERD), therefore, is the primary disorder that puts a person at risk for BE. It’s most common symptom is heartburn which affects up to 10% of the population on a daily basis and up to 44% of the population on a monthly basis.
While there are no definitive recommendations for screening, most gastroenterologists will perform an upper endoscopy, or EGD, in patients over age 50 who have a history of GERD. This allows direct visualization of the lining of the esophagus and biopsies if there is suspicion for Barrett’s. Multiple studies have suggested that the risk is highest in males over the age of 55 who are overweight or obese. It is not clear, though, if we should screen patients with acid reflux who don’t meet those criteria, although this is still routinely done. Once Barrett’s Esophagus is confirmed by a pathologist, the gastroenterologist is then faced with the decision on how often to repeat the endoscopy to assess for progression towards cancer.
The progression of Barrett’s esophagus to cancer occurs in a stepwise fashion. Reflux of acid, bile, or other intestinal contents into the esophagus results in injury to the esophageal lining. This then leads to inflammation and, in some cases, transformation (metaplasia) into a specialized intestinal lining. In some patients, this will continue to progress to dysplasia, which is a change in the cells of the lining that is much more likely to lead to cancer. Many factors determine which patients develop this higher risk change, including ongoing inflammation and genetics. Treatment of the acid reflux with a class of medicines called proton pump inhibitors (PPIs) does decrease the risk of progression to cancer, but does not completely eliminate it. Therefore, once BE is diagnosed, patients are placed in a standardized protocol for follow up endoscopies and biopsies. After the initial diagnosis, a repeat endoscopy with biopsies is typically performed one year later. If no dysplasia is found at that time, then a surveillance exam is performed every 3 years. Unfortunately, studies have not shown surveillance to be very good at preventing cancer formation, particularly in patients who have dysplasia which is much more likely to turn into cancer.
Surgically removing the esophagus previously was the only true preventative option in patients at high risk for cancer. This surgery carries significant risks and typically requires a prolonged recovery and long-term dietary modifications. Thankfully new techniques to actually treat and eliminate Barrett’s Esophagus have been developed over the last decade. Initial therapies using a laser or a technique called photodynamic therapy brought mixed results and a high risk of complications such as stricture formation.
Newer therapies developed and tested over the last five years include radiofrequency ablation (or RFA) and cryotherapy ablation. Ablation is a technique where tissue is heated or frozen until it is no longer alive. RFA (or the “Halo” procedure) has become the most widely utilized technique in our country and can be performed by gastroenterologists or surgeons with a special interest and training in this field. This procedure is performed during a standard upper GI endoscopy. Special balloon catheters can be used to treat or “ablate” large circumferential segments of Barrett’s tissue. Smaller focal areas can be treated with a catheter with electrodes mounted onto the tip of the endoscope. Clinical trials have shown that RFA completely eliminates the dysplastic or pre-cancerous tissue in greater than 90% of patients at average followup of 2.5 to 3 years. A followup study showed this response persisted out to 5 years in 92% of patients. Depending on the length of the Barrett’s segment, it usually takes at least 2-3 treatment sessions to completely eliminate the abnormal area.
RFA is now recommended by all the major endoscopy and gastroenterology societies for the treatment of all patients with Barrett’s and high grade dysplasia, and in patients with low grade dysplasia confirmed by 2 expert pathologists. Some patients with long segments of Barrett’s tissue without dysplasia may also be candidates, especially young patients (under age 40) or those with a family history of esophageal cancer. The risks of the procedure are very low; less than 1% cumulative risk of developing esophageal strictures and less than 1/1000 risk of perforating the esophagus during the procedure.
In summary, heartburn and gastroesophageal reflux can put you at risk for Barrett’s Esophagus and esophageal cancer. Therefore it is recommended that all patients with symptoms of reflux be evaluated by a gastroenterologist to assess the risk of Barrett’s and need for endoscopy. New low risk, non-invasive and highly effective therapies have been developed to treat and eliminate the pre-cancerous Barrett’s tissue and prevent progression to esophageal cancer.