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.