Dry Mouth Less Common with Intensity-Modulated Radiation Therapy
Among patients with pharyngeal squamous cell carcinoma (a type of head and neck cancer), treatment with intensity-modulated radiation therapy (IMRT) was less likely than conventional radiation therapy to result in severe dry mouth. These results were published in Lancet Oncology.
Head and neck cancers originate in the throat, larynx (voice box), pharynx, salivary glands, or oral cavity (lip, mouth, tongue). Most head and neck cancers involve squamous cells, which are cells that line the mouth, throat, or other structures.
Standard treatment for head and neck cancer is largely determined by the stage (extent to which the cancer has spread) and by the specific locations within the head or neck area where the cancer has spread.
For head and neck cancer patients treated with radiation therapy, xerostomia is a potential side effect of treatment. Xerostomia refers to an abnormally dry mouth. Patients with severe xerostomia have very limited or no saliva production. This results in difficulty eating, speaking, and swallowing, and can have a dramatic impact on quality of life.
Intensity-modulated radiation therapy is a newer approach to radiation therapy that allows for the more precise delivery of radiation to cancer cells, while sparing healthy surrounding tissue.
To test whether IMRT is less likely than conventional radiation therapy to produce dry mouth, researchers conducted a Phase III clinical trial among 94 patients with pharyngeal squamous cell carcinoma. Half the patients were assigned to IMRT that spared the parotid glands (glands that produce saliva) and half the patients were assigned to conventional radiation therapy.
- After one year, grade 2 or worse dry mouth was reported by 74% of patients treated with conventional radiation therapy and 38% of patients treated with IMRT. The only other side effect that differed significantly between groups at this point was fatigue, which was more common in the IMRT group.
- After two years, grade 2 or worse dry mouth was reported by 83% of patients treated with conventional radiation therapy and 29% of patients treated with IMRT. The two study groups had similar rates of other late side effects, as well as similar rates of recurrence and survival.
- At both the one- and two-year points, patients in the IMRT group had better recovery of saliva production and reported better quality of life.
These results suggest IMRT is less likely than conventional radiation therapy to produce dry mouth in patients with head and neck cancer.
Reference: Nutting CM, Morden JP, Harringon KJ et al. Parotid-sparing intensity modulated versus conventional radiotherapy in head and neck cancer (PARSPORT): a phase 3 multicentre randomised controlled trial. Lancet Oncology. Early online publication January 13, 2011.
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