The Beginnings of the Proof:
A 2006 study that was published in the Journal of Biological Chemistry (1) first found the extremely strong link between acid reflux and esophageal cancer. According to the study, the enzyme NOX5-S has the potential to produce unnatural stresses on cellular structure and lead to DNA damage when exposed to acid. Because a similar type of cell damage occurs in the body during the onset of acid reflux, the researchers were able to showcase the strong probability of a link between the damage caused by acid reflux and cancers inside of the body.
This study marked the first time that researchers have been able to observe and prove a direct pathway between acid reflux and esophageal cancer. Previous studies had hinted at a link, but been unable to prove such a claim.
Subsequent studies conducted by the University of Michigan, the Cleveland Clinic and others have upheld and expanded upon the findings of the Journal of Biological Chemistry study.
A lead researcher at Rhode Island Hospital and senior author Weibaio Cao summarized the findings of this and subsequent studies by stating that although the role of acid is controversial, there is definitely a negative effect within the body that is caused by the exposure of the NOX5-S enzyme to acid. The risk that an individual has of developing esophageal cancer can also be determined in a statistically significant way by measuring the signaling pathway between acid and the enzyme within the body.
Researchers were initially clued into a possibility of the link between reflux disease and cancer because of the dramatic rise in esophageal cancer over the past few decades. This report was published in CA: A Cancer Journal for Clinicians (2). General cancers of the stomach had actually been decreasing over the same time period that esophageal cancer in particular had been increased to almost seven times its initial recorded rate at the beginning of the 1960s.
The Day to Day Pathways of Cancer:
Generally accepted science has found that the following conditions are risk factors for esophageal cancer:
- Age: Though acid reflux can be found in children too, more than 80% of the cases of esophageal cancer are found in individuals aged 55 or older.
- Gender: Men are three times more likely to develop esophageal cancer than women.
- Weight: Individuals who have been diagnosed as obese are many times more likely to develop esophageal cancer than those who maintain a healthy weight.
- Smoking or tobacco use: Smokers, individuals who dip snuff and those who are exposed to second hand smoke on a day to day basis are significantly more likely to develop esophageal cancer than those whose lives are relatively smoke free.
- Alcohol: The risk of getting esophageal cancer rises with alcohol intake. The process can be reversed by drinking less alcohol.
- Diet: Individuals who eat more fruits and vegetables are at significantly less risk of developing esophageal cancer.
A link between all of the above risk factors is that a rise in the age, gender, weight, smoking, alcohol and diet risks coincide with a rise in the acid production within the body. Although not all people with these risk factors develop acid reflux, the rate of development of the condition in high risk individuals is significantly higher. High risk individuals who have not been diagnosed with acid reflux will still have higher instances of the enzyme NOX5-S in the body, which also coincides with a higher instance of esophageal cancer.
The Process of Developing Esophageal Cancer:
There are many ways in which acid reflux can affect the body to be at a higher risk of esophageal cancer. Achalasia, tylosis and esophageal webs are the most prevalent.
Achalasia refers to a condition in which the lower esophagus does not properly relax. Because of this, foods will tend to collect in the esophagus, which will become irritated, partially because of the buildup of acid.
Tylosis is a condition which causes extra layers of growth on the hands and feet. Individuals with this condition may also develop growths within the esophagus, which creates acid builds within the esophagus as well.
Esophageal webs tend to narrow the esophagus, exposing it to an increased chance of irritation from acid buildup during the process of digestion. As with achalasia, food and liquid will become stuck inside of the esophagus. Individuals with this condition will tend to have trouble swallowing and may develop brittle fingernails and irritation of the tongue.