Preventing esophageal cancer is in many, many cases tied directly to someone's acid reflux problems.
When you reflux, stomach acid goes up into your esophagus and can damage it. The damage is varied; I once had a stricture which prevented me from swallowing pills and large bits of food. Hot dogs and other meats were a big no no. In some cases, the damage can cause ulcers.
In the worst cases, the damage leads to a condition called Barrett's Esophagus. A thin barrier of sorts forms on your esophagus. I've read some theories that suggest this could be your body's natural defense trying to protect itself from the acid, by allowing stomach cells to migrate or form in the esophagus. The stomach contains a lining that protects it against acid, and Barrett's cells form a similar lining in the esophagus.
Barrett's has multiple stages. The least threatening is one where no displagia is detected; displagia is, from what I understand, a pre-cancerous change in the Barrett's cells. I actually have this condition.
Then there is Barrett's with displagia; there are two or three degrees of this, depending on how much displagia is detected. When you have this kind of Barrett's you are much more likely to get esophageal cancer than if you don't.
The best way to prevent this kind of cancer is to simply watch what you eat and control your GERD. Follow the advice of your PCP and gastro specialist regarding your diet. Keep your weight at a healthy level, avoid fatty foods, spicy foods, caffeine, alcohol, and anything that might be a "trigger" food for your reflux symptoms. If you're on some kind of PPI (Protein Pump Inhibitor) then keep taking it. These meds can not only prevent reflux but they can help heal the damage to your esophagus.
Even if you have no heartburn, you may still have acid reflux. Watch for other symptoms and keep track of when they happen. Other symptoms include tightness in the chest, sharp pain in the chest or back (especially between the shoulder blades), excessive throat phlegm, frequent coughing that has no other obvious explanation... and those are just a few. If you suffer from any of these frequently it'd be a good idea to see your PCP and mention it.
In the end, try to live a healthy lifestyle, avoid eating late at night and avoid trigger foods and drinks. If you think you have reflux, see your doctor and get a referral to a specialist, who can perform a number of tests to determine if you do or don't have it.