It used to be that smoking and drinking alcohol were the biggest risk factors for cancers that develop in the mouth and throat. Those trends may be changing, according to a new study. That new study uncovered that cancers that appear in the throat right behind the mouth have increased, primarily in developed countries. The trend has been most prevalent in men under the age of 60, the researchers found. These increases, the authors suggested, may be linked to human papillomavirus (HPV), a sexually transmitted virus that’s associated with a number of cancers, including oral cancers.
Anil K. Chaturvedi, PhD, of the National Cancer Institute, led this study that examined incidence trends for oropharyngeal (part of the throat behind the mouth) and oral cavity (mouth) cancers in 23 countries across four continents. The researchers examined the countries’ cancer registry data for the years 1983 to 2002.
In the study’s introduction, the authors noted that oral cavity cancers (OCC) have declined recently in most parts of the world due to the declines in tobacco use. At the same time, oropharyngeal cancers (OPC) have risen over the past 20 years in some countries. OPC rates were compared to those of OCC and lung cancers to distinguish the potential role of HPV from smoking-related cancer trends.
The researchers tracked specific OPC sites, including base of the tongue, tonsils, oropharynx and pharynx (throat). OCC sites included the tongue, gums, floor of the mouth, palate (roof of the mouth) and other areas of the mouth.
Here’s what the researchers learned:
- OPC increased significantly among men in the United States, Australia, Canada, Japan and Slovakia. Incidence trends for OCC in these countries were either not significant or there was a significant decline in OCC.
- Among women, there was an increase in both OPC and OCC cases in Denmark, Estonia, France, the Netherlands, Poland, Slovakia, Switzerland and the United Kingdom.
- In Denmark and the United Kingdon, both OPC and OCC increased significantly, with stronger increases seen in OPC than in OCC.
- Increasing OPC incidence in men was accompanied by decreasing incidence in lung cancer.
- For women, however, increasing OPC incidence occurred at the same time as increasing Lung Cancer incidence.
- OPC incidence rose substantially more for younger men under the age of 60 than in older ages in the United States, Australia, Canada, Slovakia, Denmark and the United Kingdom.
- For OCC, a similar statistically significant increase at younger ages was seen only in the United Kingdom, while OCC incidence decreased significantly at younger ages in the United States, Australia and Canada.
The authors of this study pointed out that recent research has suggested that about 60 to 70 percent of OPCs in the US are caused by HPV infection, compared with less than 10 percent in less economically developed areas. The researchers wrote, “Our results underscore the potential for increasing global relevance of HPV as a cause of OPC.”
They added that the reasons for higher increases seen in men are not clear and warrant more investigation.
“This male predominance also has important implications for male HPV vaccination policy in several countries,” according to the researchers.
Meanwhile, tobacco and alcohol use remain major risk factors for both OPC and OCC, with OCC incidence two to four times higher than OPC in most parts of the world, “…underscoring the need for prevention strategies targeted toward tobacco and alcohol use,” the authors concluded.
1. This study was published November 18 in the Journal of Clinical Oncology.
2. The research was supported by the National Cancer Institute and by a grant from the Institut National du Cancer.
3. One of the authors disclosed financial ties with two pharmaceutical companies.