乌鸦传媒

PHOENIX -- Patients with head and neck cancer had substantial sparing of oral mucosa when they used custom-made dental stents to shield normal tissue from radiation therapy, data from a small clinical series showed.

The shielding devices spared an average of 48 cc of normal tissue among 37 patients. Mean tissue-sparing increased to 59 cc in patients with nasopharyngeal and paranasal sinus tumors.

No patient had a severe mucosal reaction, Lindsay Sales, MD, reported here at the Multidisciplinary Head and Neck Cancer Symposium.

"We work with dental specialists to make a device that is customized to fit a specific patient," Sales, of the University of Washington in Seattle, told 乌鸦传媒. "No two devices are exactly the same size or shape.

"The dental stents are an inexpensive way to prevent severe mucosal reactions, and patient acceptance has been good," she added.

Each device costs about $200 to produce.

Simple bite-blocks and corks afford limited protection from radiation exposure to uninvolved tissues. The non-customized devices yield inconsistent results, and many patients find them uncomfortable and difficult to use.

For several years, head and neck oncologists at the University of Washington have worked with dental specialists to fashion customized tongue-displacing dental stents from a light-cured acrylic resin material. Each device consists of maxillary/mandibular arches and a paddle for tongue displacement (depression, deviation, or both).

To describe their experience with the devices, Sales and colleagues retrospectively reviewed records of patients with head and neck cancer treated from 2008 to 2011. All of the patients had stage III-IVb carcinoma, and primary tumor sites comprised the oral cavity (except tongue primaries), oropharynx, nasopharynx, and paranasal sinuses.

Definitive chemoradiation was used in each case, and all but one patient received intensity modulated radiation therapy. Each patient received a cumulative radiation dose of 70 Gy to the primary tumor.

Investigators compared treatment-planning CT scans with and without the dental stents to estimate the amount of displaced oral mucosa that would been exposure to radiation without the device.

Sales said all patients tolerated use of the stents, and no unexpected mucosal reactions occurred as a consequence of chemoradiation therapy. No patient has worse than grade III mucositis at any time.

The total volume of mucosa spared ranged from 23 to 95 cc. The percentage of displaced mucosa that was spared from exposure to radiation was 76% with 35 Gy, 48% with 50 Gy, 22% with 66 Gy, and 8% with 70 Gy.

Patients with stage III disease had more tissue-sparing than did patients with stage IV cancer (66 versus 46 cc). Weight loss during treatment averaged 8%, and no patient required unplanned treatment breaks.

"Customized tongue-displacing dental stents achieve superior oral mucosal sparing, provide reproducible immobilization, are well tolerated, and can readily be incorporated into clinical practice," Sales and colleagues concluded in their poster presentation.

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