Nikhil Prasad Fact checked by:Thailand Medical News Team Jun 15, 2026 1 hour, 10 minutes ago
Medical News: A major new Japanese study has found that people diagnosed with gastrointestinal (GI) cancers often have significantly worse oral health than the general population, raising fresh concerns that chronic dental problems may play a larger role in cancer development than previously believed. Researchers discovered that patients with cancers affecting the digestive system had substantially higher levels of tooth decay, severe gum disease, and hidden dental infections, suggesting that long-term oral disease could be linked to cancer-related processes in the body.
Study finds gastrointestinal cancer patients have significantly higher rates of tooth decay, gum disease, and hidden dental
infections than the general population.
Researchers Uncover a Broader Oral-Cancer Connection
The study, titled “Comprehensive Evaluation of Oral Diseases in Patients with Gastrointestinal Cancers: Epidemiological Evidence from a 10-Year Retrospective Study,” was conducted by scientists from the Department of Operative Dentistry at Hokkaido University Hospital, the Department of Restorative Dentistry at the Hokkaido University Graduate School of Dental Medicine, the Department of Restorative Dentistry at the Hokkaido University Faculty of Dental Medicine, and the Department of Gastroenterology and Hepatology at the Hokkaido University Faculty of Medicine in Japan.
While previous research has mainly focused on gum disease as a possible contributor to gastrointestinal cancers, this investigation took a much broader look. The researchers examined not only periodontal disease but also tooth decay and apical periodontitis, a serious infection at the root of a tooth that often goes unnoticed until significant damage has occurred.
The team analyzed oral health records from 218 patients with gastrointestinal cancers who underwent dental evaluations between 2015 and 2025. Their findings were then compared with national dental health data from Japan.
Tooth Decay Levels Were Consistently Higher
One of the most striking findings involved the DMFT score, a standard dental measurement that records the number of decayed, missing, and filled teeth throughout a person's lifetime.
Across every adult age group studied, GI cancer patients had significantly higher DMFT scores than the national average. For example, individuals aged 45 to 54 had an average DMFT score of 20.1 compared with 13.4 in the general population. Among those aged 55 to 64, the score was 22.7 compared with 15.7 nationally. Similar differences were seen in older age groups.
Researchers believe this is important because the DMFT score reflects a lifetime history of oral disease and chronic exposure to harmful oral bacteria. Rather than showing a temporary dental problem, it acts as a record of long-term oral health damage accumulated over many years.
Hidden Dental Infections Were Extremely Common
Another alarming discovery was the high prevalence of apical periodontitis. Overall, 46.3 percent of cancer patients had at least one infected tooth root lesion. In some age groups the numbers were even higher.
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Among patients aged 45 to 54, more than 56 percent had apical periodontitis, while nearly 65 percent of those aged 65 to 74 were affected. Many patients had multiple infected lesions at the same time.
These infections can continuously release bacteria and inflammatory substances into the bloodstream, potentially contributing to widespread inflammation throughout the body.
Severe Gum Disease Also Stood Out
The researchers also found dramatically elevated rates of severe periodontal disease. Deep periodontal pockets, a key sign of advanced gum disease, were much more common among GI cancer patients than among the general Japanese population.
For patients aged 65 to 74, nearly 95 percent had periodontal pockets measuring at least 4 millimeters, compared with just over 56 percent in national survey data. Severe pockets measuring 6 millimeters or more were also far more prevalent, indicating extensive gum damage and inflammation.
This
Medical News report notes that the combination of severe tooth decay, gum disease, and root infections points to what researchers describe as “oral disease clustering,” where multiple chronic oral conditions occur together and may collectively influence overall health.
How Could Oral Diseases Affect Cancer Risk?
The scientists proposed several possible explanations. Harmful oral bacteria may travel from the mouth into the digestive tract, where they could alter the gut environment and influence cancer-related biological processes. Certain oral microbes have already been detected in colorectal tumors in previous research. Another possibility is chronic inflammation. Long-standing dental infections and gum disease can repeatedly expose the body to inflammatory molecules and bacteria. Over many years, this persistent inflammatory burden may create conditions that support cancer development or progression.
The researchers emphasized that their study does not prove that oral disease causes gastrointestinal cancer. However, the strong association observed suggests that the relationship may be more complex than previously understood and extends beyond gum disease alone.
Conclusions
The study provides compelling evidence that patients with gastrointestinal cancers frequently carry a much heavier burden of oral disease than the general population. Elevated levels of tooth decay, severe periodontal disease, and chronic root infections were observed across multiple age groups, suggesting that long-term oral health problems may be closely intertwined with gastrointestinal cancer biology. Although the findings cannot establish cause and effect, they highlight the possibility that cumulative oral inflammation and microbial imbalances could contribute to cancer-related processes over time. The researchers believe that future large-scale studies should explore whether improving oral health could help reduce cancer risk or improve outcomes for patients already diagnosed with GI cancers. Comprehensive dental assessments may eventually become an important part of cancer prevention and management strategies.
The study findings were published in the peer reviewed journal: Cancers.
https://www.mdpi.com/2072-6694/18/12/1941
For the latest on gastrointestinal cancers, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/articles/cancer
https://www.thailandmedical.news/articles/dental-news
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