Volume 10, Issue 4
Dentists advise resolving tooth and gum issues before starting cancer treatment.
Bettye Davis admits she has never had very good teeth. But when she received a diagnosis of salivary gland cancer, she was surprised that her oncologist recommended she visit a dentist before beginning radiation treatments to her jaw.
“When we first saw her, she still had quite a few teeth, but she had severe periodontal disease and severe bone loss,” says Dennis Abbott, DDS, Davis’ dentist. Knowing radiation would do more damage, he recommended removing the remainder of her teeth and allowing time to heal before she began 33 radiation treatments.
“We knew that if we took the teeth out after radiation, we risked the bone not healing well, which would have meant osteonecrosis, dead bone in her mouth, and lots of systemic problems.”
According to the National Cancer Institute, eliminating pre-existing dental and mucosal infections and instituting a comprehensive oral hygiene protocol before and throughout therapy can reduce the severity and frequency of oral complications from cancer therapy. Abbott says the NCI recommendations, as well as an increasing number of studies, are bringing more recognition to the importance of dental issues before, during and after cancer treatment.
Abbott’s goal is to help patients maintain healthy teeth and reduce the risk of future infection with an oral care plan that eliminates or stabilizes disease that could produce complications during or following therapy. These complications can range from irradiated bone and gums not healing properly to an oral bacterial infection spreading throughout the body due to chemotherapy-induced immunosuppression.
Radiation to the head and neck area can also cause severe dry mouth (xerostomia) and loss of the protective effects of saliva, which accelerates existing tooth decay and can damage tiny blood vessels in the bone that deliver nutrients and oxygen that allow the bone to grow. So any tooth extractions or invasive dental procedures in irradiated bone are likely to result in slow healing, leading to pain and infection.
Oral complications may be acute (developing during therapy) or chronic (developing or continuing long after therapy), with the most common and significant being oral mucositis (inflammation and ulcers in the lining of the mouth), salivary gland dysfunction, taste dysfunction, pain and dry mouth. Limited or no saliva can lead to increased risk of infections in the mouth, gum disease and dental disease, which can progress rapidly and be difficult to control.
Available medications to stimulate saliva production rely on residual salivary gland function, if enough function remains. Mouth gels, rinses and sprays can moisturize the mouth, but unlike natural saliva, they don’t contain antibodies; growth and repair factors; fluoride; and calcium phosphates that help keep teeth healthy and strong.
Abbott says this means patients must be proactive in caring for their teeth to prevent cavities. Topical antimicrobials or antiseptics can also help control infections, including dental decay related to acid-producing bacteria.
With radiation therapy directed at her salivary glands, Davis, 73, experienced extreme dry mouth, especially at night. But, she says, a mint-flavored antioxidant topical gel Abbott prescribed, AO ProVantage, effectively relieved this symptom. “It has really helped because it keeps your mouth refreshed, plus it helps you have more moisture in your mouth,” Davis says.
The decision to extract teeth prior to radiation, Abbott says, is based on the health of the tooth, the condition of the gums and bone around the tooth, the amount of radiation the bone around the tooth is scheduled to receive and the area that will be radiated. Gum disease is a cause for tooth extraction prior to therapy. Other causes include problems with previous root canals, tooth fractures and broken fillings that can’t be adequately restored.
“You can’t dismiss oral health because it affects systemic health,” Abbott says. “The mouth has a huge amount of bacteria, and if it’s not taken care of, there is the risk of that bacteria getting into the bloodstream.”
The American Dental Association recommends all cancer patients schedule a dental exam at least two weeks before beginning treatment. This should involve a full comprehensive exam, gum probing around every tooth and X-rays. It may also include removal of local sites of irritation, such as broken teeth, or identifying chronic infections, such as gum disease.
“Those conditions need to be managed up front because we are very limited after treatment and the complication risk is so significant that not doing it before can lead to significant difficulties after,” says Joel Epstein, DMD, MSD, director of oral medicine services at City of Hope Cancer Center in Duarte, Calif.
Appropriate healing time for dental care prior to treatment is imperative, Epstein adds, because a surgically treated area in the mouth becomes vulnerable to bacteria. Patients with suppressed immune systems can develop infection, which could result in a treatment delay or dose reduction, ultimately affecting the treatment outcome and survival.
Epstein says two weeks of healing time is ideal, but the overall goal is to have the right dental treatment coordinated with medical therapy to avoid those types of risks. Therefore communication between the dentist and oncology team is key.
Treating dental issues during cancer therapy is possible but can be difficult and can also lead to complications, such as infection in patients on immunosuppressing chemotherapy and delayed healing of affected oral tissue in patients receiving high-dose radiation.
If dental treatment is needed during a cycled chemotherapy, it must be coordinated between cycles and at a time when white cell counts are high, Epstein says.
For patients receiving radiation for head and neck cancers, the dentist needs to understand the risks for healing and communicate with the oncologist to understand which regions are involved in the radiation fields, Epstein says. The dentist should also be aware of any previous or ongoing bisphosphonate use and understand the associated risks.
“We function as a part of the oncology team for all of our patients,” Abbott says. “I understand the blood work that I get back, and I understand what it is that I need to look for in order to keep the patient safe and then develop my treatment plan around that.”
A less common but significant oral complication involves bone healing, or lack thereof. Because radiation can damage bone cells, limiting their ability to heal, any future trauma or surgery to irradiated bone can cause osteonecrosis, or bone death.
Bisphosphonates and the RANK ligand inhibitor Xgeva (denosumab)—used to maintain bone density and prevent fractures in people with bone metastases—have also been associated with increased risk for osteonecrosis of the jaw (ONJ), which can occur in 1 to 2 percent of patients on these therapies, according to a 2010 study published in the Journal of Clinical Oncology.
A study published in 2009 in Annals of Oncology showed that preventive dental measures can significantly decrease the risk of developing ONJ. In 2003 and 2004, the FDA updated inserts for the intravenous bisphosphonates Aredia (pamidronate) and Zometa (zoledronic acid) recommending a dental exam with preventive dentistry prior to cancer treatment.
“The main prevention is treatment of the at-risk dental conditions before you’ve had a long-term effect on the bone,” Epstein says. The FDA also warns against invasive dental procedures if possible during or following bisphosphonate use, noting that the majority of reported cases of ONJ have been associated with dental procedures, such as tooth extraction, and many had signs of local infection.
Whether a tooth is extracted from an irradiated area or following bisphosphonate use, Epstein says it must be done carefully. “You want a specialist surgeon to do that with coordination with the cancer center and with people who have supported this need before.”
After her diagnosis of metastatic renal cell carcinoma in 2009, Linda Morris had two extractions before starting Zometa. When an exposed jaw area wouldn’t heal, she developed osteonecrosis. After visiting six dentists over two years, the 67-year-old saw Abbott.
To prevent infection, Abbott had her apply AO ProVantage twice daily and rinse her mouth with non-alcoholic antibacterial chlorhexidine, as well as clean her teeth with a water flosser. To promote healing, Abbott removed necrotic tissue and performed a comprehensive cleaning every two weeks. For the first time, Morris began to see progress.
“The biggest problem I had was not being able to find the dental care I needed,” Morris says.
“The topically applied gel has made a huge difference in how we can treat this problem,” Abbott says. “We’ve had two cases where the necrotic bone has been totally resolved.”
Those conditions need to be managed up front because we are very limited after treatment and the complication risk is so significant that not doing it before can lead to significant difficulties after.