Oral cancer is a general term used to describe cancerous tissue located in the lips, gums, mouth floor, cheek linings, tongue, or in the soft or hard palate in the roof of the mouth. In many cases, cancers in these tissues belong to a group of cancers known as squamous cell carcinomas; these carcinomas spread relatively quickly and can produce serious health repercussions far beyond the mouth and its structures. Most people know that smoking and the use of other tobacco products seriously increase risks for the onset of oral cancer. However, a clear majority of people with cancers of the mouth also drink excessive amounts of alcohol.
Strictly speaking, oral cancers only appear in the structures contained inside the mouth; another group of similar cancers, called oropharyngeal cancers, appear in the structures that form the throat. Depending on their specific location, cancers in the tongue or soft palate may be viewed as either oral or oropharyngeal cancers. Roughly 90 percent of all oral and oropharyngeal cancers originate in cells called squamous cells, which form the skin-like surfaces inside the mouth, as well as actual skin on the body’s exterior surfaces. The remaining 10 percent of cancers in the mouth or throat appear in glandular tissue (the saliva glands, adenoids, or lymph glands), or in the melanin-producing pigment cells.
Smoking and the use of smokeless tobacco are the two main factors in the development of oral cancer. In addition to excessive alcohol consumption, other potential contributing factors include maintenance of poor oral and dental hygiene habits, use of medications that diminish normal immune function, the presence of a mouth ulcer, repeated irritation from fillings or dentures, and the presence of an HPV (human papillomavirus) infection in the body. More than 50 percent of all oral cancers are only discovered after they spread to the throat, neck or some other location, the US National Library of Medicine reports. While roughly 90 percent of people whose cancer hasn’t spread (metastasized) will survive for at least five years after diagnosis, very few people with metastasized oral cancer survive this long.
Alcohol has toxic effects on a wide variety of cells located throughout the body. Much of this damage occurs when cells (especially those located in the liver) attempt to break down individual alcohol molecules and eliminate them from the body. This breakdown process produces a substance called acetaldehyde, which is also toxic and can increase risks for cancerous changes in exposed cells. Acetaldehyde is especially associated with the onset of cancerous changes in the mouth, throat and other portions of the upper digestive tract, the authors of a study published in 2009 in the journal Addiction report. In turn, people who regularly drink excessive amounts of alcohol have greater chances of developing acetaldehyde-related cancer than moderate drinkers or people who don’t drink at all.
Roughly 75 percent of all people with oral or oropharyngeal cancers regularly consume alcohol in amounts that exceed moderate levels (two drinks a day for men and one drink a day for women). When compared to moderate drinkers or non-drinkers, heavy drinkers develop these cancers anywhere from three to six times as frequently. Specific increases in alcohol-related cancer risks vary according to the part of the mouth or throat under consideration. In all likelihood, risks remain the same regardless of the specific type of alcohol (wine, beer, liquor, etc.) that a given drinker prefers.
People who drink heavily and smoke moderately are roughly twice as likely to develop oral or oropharyngeal cancer as people who just drink heavily or people who just smoke. Compared to people who don’t smoke or drink at all, people who drink heavily and smoke heavily may have as much as 35 times the risks for mouth or throat cancer. Doctors refer to the combined effects of alcohol and smoking as a comorbid relationship. This type of relationship occurs whenever simultaneous use of two or more substances, or the simultaneous presence of two or more diseases, triggers health outcomes that are significantly worse than use of a single substance or the presence of a single disease could cause on its own.
In the past, some researchers have voiced concern that daily use of alcohol-containing mouthwashes could potentially elevate a person’s lifetime risks for the onset of oral or oropharyngeal cancer. However, according to the results of a variety of studies conducted throughout the 2000s, the amount of alcohol contained in these products does not increase cancer risks, even when used regularly.