The link between gum disease and cancer is a controversial one, but there is some evidence that it exists. The National Cancer Institute says the relationship is unclear because of the different types of cancer that are linked to gum disease. In addition, only certain types of cancer appear to be associated with gum disease; other cancers are linked to factors such as smoking. Some researchers believe that inflammation caused by periodontal disease may contribute to an increased risk of cancer. For example, in men, periodontal disease is associated with a higher incidence of prostate cancer.

Though rare, oral cancer is linked to gum disease. “When you have deep pockets and pus-filled gums, the bacteria in the mouth can get under the skin and migrate into the lymph nodes, where they multiply and eventually cause cancer,” says McClain. Gum disease can spread from the tongue, lips, cheeks, floor of the mouth, and palate to the base of the skull and neck. It’s possible that this connection isn’t just a statistical association but a causal one.

“It’s unclear why, but in certain situations the combination of gum disease and smoking can lead to more cancers of the mouth, throat, and neck,” says McClain. In addition to increasing the risk of cancer, gum disease is also associated with melanoma and leukemia.