ST. PETERSBURG, FloridaXerostomia, or mouth dryness, typically seen acutely with head and neck radiation, is also the most common late complication following radiation therapy for head and neck cancer, Avraham (Avi) Eisbruch, MD, said at the LENT (Late Effects of Normal Tissues) IV workshop on late effects criteria and applications. Dr. Eisbruch is associate professor of radiation oncology, University of Michigan Medical School, Ann Arbor.
"Xerostomia is a major cause of reduced quality of life in survivors," Dr. Eisbruch said. In addition to its effects on subjective well-being, it can cause alterations in speech; changes in taste and swallowing contributing to malnutrition; and oral pathology, including mucosal fissures, ulcerations, candidiasis, dental caries, and even osteonecrosis.
As the salivary glands are highly sensitive to radiation, xerostomia usually begins early in radiation therapy. In the first week of a 7-week course of radiation therapy, saliva output may decrease to 10% to 40% of pretherapy levels. If the radiation dose is relatively low, saliva output may recover, but with standard doses, xerostomia is usually permanent.
Late xerostomia differs from the acute form in that thick, sticky saliva disappears as mucinous secretions decline, whereas with acute xerostomia, serous secretions decrease early in response to radiation therapy.
"Through this conference, we hope to define how best to measure xerostomia," Dr. Eisbruch said. "There are several validated scales, but our hope is to choose one that will allow us to compare different treatments using the same language."
Current methods to measure xerostomia include patient-reported scales, clinician-rated instruments, and objective measures for documenting injury and for use in intervention studies. As both salivary output and symptoms improve continuously with years elapsed since radiation therapy, reporting measures of xerostomia need to state clearly the time points used.