Dental problems caused by radiation, chemotherapy should be treated before a child undergoes immunosuppression as part of bone marrow transplantation therapy

Many children who undergo bone marrow transplantation (BMT) as part of cancer treatment already have dental abnormalities that leave them vulnerable to potentially life-threatening bacterial infections, according to investigators at St. Jude Children's Research Hospital. A report on this study appears in the prepublication online edition of Bone Marrow Transplantation.

The investigators found that the most common dental problem in children about to undergo BMT was tooth decay, often resulting from neglected oral hygiene and poor nutrition. Tooth decay is especially dangerous in children undergoing BMTs because physicians must first suppress their immune systems to reduce the chance of transplant rejection. Therefore, children about to undergo immunosuppression as part of BMTs should have dental checkups, said Sue C. Kaste, D.O., a member of St. Jude Radiological Sciences. "It's important to make sure they do not have cavities that could act as doorways to the bloodstream for disease-causing bacteria," she said.

The St. Jude investigators made their findings during a retrospective study of the medical records and X-rays of the entire set of teeth in 259 children (age range 3.2 to 25.9 years) who underwent BMT. The most common diagnosis among these children was leukemia (63 percent); while the other children were found to have solid tumors (14 percent), anemia (8 percent), or brain tumors (3 percent). In addition, one child had retinoblastoma (eye cancer) and one had severe combined immunodeficiency. One hundred fifty of these patients were male, 203 were Caucasians and 38 were African-American.

The St. Jude team found that, before BMT, 150 (57.9 percent) of the 259 patients had dental abnormalities. Among patients who still had their "first" teeth before BMT, 36.4 percent had dental abnormalities; among patients with permanent teeth, 66.7 percent had dental abnormalities; and among patients with both first and permanent teeth, 52.3 percent had abnormalities. There was no difference in frequency of abnormalities in permanent teeth between males (65.5 percent) and females (67.5 percent), nor was there a difference between Caucasians (69 percent) and African-Americans (70 percent).

The most common dental abnormality identified in the study was caries (tooth decay), which was seen in 133 (51 percent) patients. Among other dental problems were abnormal clumps of enamel on the tooth and calcification (hardening) of the tooth pulp (the soft inner matter in teeth containing nerves and blood vessels).

A variety of factors can cause tooth decay in pediatric patients who later undergo BMTs. For example, previous studies by other researchers have found that children receiving chemotherapy and radiation are at increased risk of tooth damage that causes decay. Radiation can also reduce the amount of saliva released by the mouth's salivary glands, which in turn can lead to growth of decay-causing bacteria.

Some children undergoing cancer treatment also develop ulcers in the lining of their mouths, which discourage them from eating certain foods. Instead, these children prefer sweet foods, which don't sting, but do promote tooth decay. In addition, some children undergoing cancer treatments must consume high levels of carbohydrates to ensure they get enough calories, which also encourages the growth of decay-causing bacteria.

Since small cuts in the tissue around teeth caused by brushing could become serious sources of blood loss, children are sometimes forbidden to brush their teeth if they suffer from severely reduced levels of platelets--blood cells that trigger clot formation. Finally, young children often cannot brush their own teeth properly, and their parents might fail to brush their children's teeth.

"Our findings clearly show that children about to undergo bone marrow transplantation should be examined for dental problems that might promote infections," said Christopher C. Rowland, D.D.S., the dentist in the Department of Surgery at St. Jude and a co-author of the paper. "This is also an opportune time to educate patients and parents about proper oral hygiene. Meticulous dental care can minimize the development of therapy-related caries. Follow-up examinations after transplantation and immunosuppression will also help to minimize sources of potential infection."

Other authors of the paper include Mitchell D. Vaughan (University of Tennessee Health Science Center, Memphis); Xin Tong, D. Kumar Srivastava, Gregory A. Hale and Richard Rochester (St. Jude).