Non-smokers with oral precancerous lesions at increased risk of cancer

March 7, 2018, University of British Columbia
UBC dentistry PhD candidate Leigha Rock found that oral precancerous lesions in non-smokers are more than twice as likely to progress to cancer. Credit: Moss/Flickr

Precancerous lesions in the mouths of non-smokers are more likely to progress to cancer than those in smokers, new research from the University of British Columbia has found.

Although tobacco use is still one of the strongest risk factors associated with mouth cancers, UBC dentistry PhD candidate Leigha Rock found that oral precancerous lesions in non-smokers are more than twice as likely to progress to . Furthermore, lesions in non-smokers progressed to cancer faster than smoking-associated lesions. The study was published this week in Oral Oncology.

"This is the first published study where the main focus was to examine the difference in risk of progression to oral cancer between non-smokers and smokers with oral precancerous lesions," said Rock, lead author of the study. "While other studies have also reported a higher rate of transformation among non-smokers, we looked at multiple risk factors including genetic markers."

Rock and colleagues looked at case history of 445 patients with oral epithelial dysplasia (OED), a type of precancerous oral lesion, enrolled in the B.C. Oral Cancer Prediction Longitudinal study. One-third of the patients were non-smokers.

"As smoking rates decline, we are seeing an increase in the proportion of these types of lesions in non-smokers," said Rock.

Among the scientists' findings were that lesions on the floor of the mouth in non-smokers were 38 times more likely to progress to cancer than in smokers. The study is also the first to report on quicker progression to cancer in non-smokers: both three-year and five-year rates of progression were seven per cent and 6.5 per cent higher than smokers, respectively.

The researchers suggest that the marked difference in outcomes is due to a difference in the root causes of the lesions. In smokers, the OED is likely the result of environmental factors, whereas in non-smokers, genetic susceptibility or mutations are likely to blame.

"Our findings show that molecular genomic markers can identify high risk , regardless of risky habits like smoking, and should be an important consideration in patient management," said Rock.

The study's results stress the importance of taking seriously, especially when they occur in non-smokers: "If you see a lesion in a smoker, be worried. If you see a lesion in a non-smoker, be very worried. Don't assume it can't be cancer because they're a non-smoker; our research indicates may be at higher risk."

Explore further: Even smokers may benefit from targeted lung cancer treatments

More information: L.D. Rock et al, Characterization of epithelial oral dysplasia in non-smokers: First steps towards precision medicine, Oral Oncology (2018). DOI: 10.1016/j.oraloncology.2018.01.028

Related Stories

Even smokers may benefit from targeted lung cancer treatments

December 13, 2017
Smokers are less likely than non-smokers to have lung cancers caused by targetable genetic changes. But a study published this week in the journal Clinical Cancer Research shows that when they do, smokers benefit just as ...

Who are you without that cigarette?

November 14, 2017
Do you want to be successful at stopping smoking? If so, the main thing is that you should see yourself as a non-smoker. Psychologist Eline Meijer has discovered that smokers who are unable to do this are more likely to resume ...

Increased oral pathogens, decreased bacterial diversity predict precancerous stomach cancer lesions

November 27, 2017
Elevated pathogen colonization and a lack of bacterial diversity in the mouth were identified in people with precancerous lesions that could precede stomach cancer, finds a new study led by New York University College of ...

Among colon cancer patients, smokers have worse outcomes than non-smokers

February 8, 2017
In an analysis of more than 18,000 patients treated for colon cancer, current smokers were 14 percent more likely to die from their colon cancer within five years than patients who had never smoked.

Location of oral cancers differs in smokers, nonsmokers

November 6, 2014
The location of oral cancers differed in smokers and nonsmokers with nonsmokers having a higher proportion of cancers occur on the edge of the tongue, according to a study published online by JAMA Otolaryngology-Head & Neck ...

CDC: Fewer smokers go to the dentist

February 7, 2012
Smokers not only have more problems with their teeth than non-smokers, they also go to the dentist less often.

Recommended for you

Researchers create a drug to extend the lives of men with prostate cancer

March 16, 2018
Fifteen years ago, Michael Jung was already an eminent scientist when his wife asked him a question that would change his career, and extend the lives of many men with a particularly lethal form of prostate cancer.

Machine-learning algorithm used to identify specific types of brain tumors

March 15, 2018
An international team of researchers has used methylation fingerprinting data as input to a machine-learning algorithm to identify different types of brain tumors. In their paper published in the journal Nature, the team ...

Higher doses of radiation don't improve survival in prostate cancer

March 15, 2018
A new study shows that higher doses of radiation do not improve survival for many patients with prostate cancer, compared with the standard radiation treatment. The analysis, which included 104 radiation therapy oncology ...

Joint supplement speeds melanoma cell growth

March 15, 2018
Chondroitin sulfate, a dietary supplement taken to strengthen joints, can speed the growth of a type of melanoma, according to experiments conducted in cell culture and mouse models.

Improved capture of cancer cells in blood could help track disease

March 15, 2018
Tumor cells circulating throughout the body in blood vessels have long been feared as harbingers of metastasizing cancer - even though most free-floating cancer cells will not go on to establish a new tumor.

Area surrounding a tumor impacts how breast cancer cells grow

March 14, 2018
Cancer is typically thought of as a tumor that needs to be removed or an area that needs to be treated with radiation or chemotherapy. As a physicist and cancer researcher, Joe Gray, Ph.D., thinks differently.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.