VANCOUVER – A BC research team has identified a set of molecular markers that can better determine whether individuals with oral pre-cancerous lesions are at high risk of having those lesions progress to oral cancer.
The findings were published today in Cancer Prevention Research and represent the only large-scale population study with long-term follow up.
The study was led by Dr. Miriam Rosin, director of the BC Cancer Agency’s BC Oral Cancer Prevention Program, and validated the “loss of heterozygosity” (LOH) analysis the team first discovered 10 years ago. This analysis successfully identified a change in the DNA of genes in specific chromosomes that have been shown to be highly predictive of the development of oral cancer.
Highlights of the findings:
• Patients with oral lesions can be grouped according to risk level.
• Two out of every three high-risk patients progressed to cancer.
• Follow-up and treatment could be tailored to a patient’s risk level.
Oral cancers are a global public health problem with close to 300,000 new cases identified worldwide each year.
Many oral cancers are preceded by pre-cancerous lesions. Severe lesions are
associated with a high cancer progression risk and should be treated definitively. The challenge within the field, however, has been to distinguish which low-grade lesions are the most likely to progress to cancer.
In 2000, Rosin and colleagues studied existing samples of oral premalignant
lesions where progression to cancer was known to have occurred. From those samples, they developed a method for grouping patients into low-risk or high-risk categories based on differences in their DNA.
The current study confirmed the findings from 2000 and also identified two new DNA risk markers that allowed researchers to categorize patients into low, intermediate and high-risk groups.
Compared to low-risk lesions, intermediate-risk lesions have an 11.6-fold increase in progression to cancer, while high-risk lesions have a 52.1-fold increase in progression risk.
The likelihood that low-risk lesions will progress to cancer in five years is 3.1 per cent, while for intermediate-risk lesions, the likelihood jumps to 16.4 per cent in five years and for high-risk lesions, the likelihood is 64.1 per cent.
Dr. Miriam Rosin, director of the BC Cancer Agency’s BC Oral Cancer Prevention Program.
“This study is momentous not only because we were able to validate important oral cancer markers identified a decade ago, but also because we discovered new markers that further refine our knowledge of the chances an oral lesion will become cancerous.”
“There is now a way to differentiate low-risk from high-risk lesions,” said Rosin. “With this knowledge, it is possible to help clinicians identify more appropriate procedures to use on patients and spare individuals with low-risk lesions the discomfort of aggressive treatment.”
A large team of clinicians and scientists contributed to this body of work. Partners include Simon Fraser University, the Oral Biopsy Service at the University of British Columbia and Vancouver General Hospital, the dentistry clinics at the BC Cancer Agency’s Vancouver Centre and Fraser Valley Centre and the oral mucosal clinics at Vancouver General Hospital and the University of British Columbia. The project was funded in large part by the National Institute of Health and the National Institute of Dental and Craniofacial Research with additional funding from the BC Cancer Foundation to support community engagement.
The BC Cancer Agency, an agency of the Provincial Health Services Authority, is committed to reducing the incidence of cancer, reducing the mortality from cancer, and improving the quality of life of those living with cancer. It provides a comprehensive cancer control program for the people of British Columbia by working with community partners to deliver a range of oncology services, including prevention, early detection, diagnosis and treatment, research, education, supportive care, rehabilitation and palliative care. For more information, visit www.bccancer.ca.