AHRQ: IMRT alleviates 'dry mouth,' but may not better reduce tumor size

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Eclipse IMRT plan for head and neck cancer. Image Source: Varian

Intensity-modulated radiation therapy (IMRT) is more successful than traditional radiation therapy in avoiding "dry mouth" when treating head and neck cancers, but it is unknown whether the treatment is better or worse at reducing the size of tumors, based on a comparative-effectiveness review funded by the Department of Health and Human Services' (HHS) Agency for Healthcare Research and Quality (AHRQ). 

The report found that IMRT leads to fewer cases of xerostomia, commonly known as dry mouth, than other types of radiation. Xerostomia, a potential side effect to radiation when salivary glands are damaged, can affect basic functions like chewing, swallowing and breathing; senses such as taste, smell and hearing; and can significantly alter a patient's appearance and voice.

However, according to the agency, the report did not find evidence that IMRT is more successful than any other kind of radiation therapy in reducing tumors. Many scientists consider IMRT to be theoretically better able to target cancerous cells while sparing healthy tissues, but more research is needed.

"The development of new technologies to treat cancer has been one of the true success stories of American medical research," said AHRQ Director Carolyn M. Clancy, MD. "This report provides patients and their doctors with more information about these advances, which they can use to make more informed choices about their own treatment."

The report examined treatment for cancers to the head and neck, including the mouth, larynx and sinuses. Non-brain head and neck cancers account for up to 5 percent of cancers that are diagnosed in the U.S., with an estimated 47,560 new cases and 11,260 deaths in 2008.

In this comparative-effectiveness review, researchers also examined the evidence regarding proton-beam radiation therapy, a technology that some clinicians believe targets radiation even more precisely than IMRT. However, researchers did not find enough evidence to draw any conclusions regarding the benefits or potential side effects of proton-beam therapy, which is more commonly used to treat prostate cancer and pediatric tumors.

In an AHRQ technical brief published last fall, researchers found limited evidence regarding whether proton beam radiation therapy is safer or more effective than other types of radiation to treat cancer. According to the agency, the newest research review from its Effective Health Care Program represents the federal effort to compare alternative treatments for health conditions to choose the most effective treatments.

In conjunction with the new report, AHRQ said it will soon publish in plain-language summary guides about radiation therapy for head and neck cancer treatment for patients, clinicians and policymakers. Summary guides on numerous clinical topics such as medicines to reduce the risk of breast cancer and choosing pain medicine for osteoarthritis, as well as other information and background on the Effective Health Care Program, can be found at here

The comparative-effectiveness review was authored by the Blue Cross and Blue Shield Association, Technology Evaluation Center in Chicago.