Assessment of Risk of Xerostomia After Whole-Brain Radiation Therapy and Association With Parotid Dose.

Importance: Whole-brain radiation therapy (WBRT) delivers a substantial radiation dose to the parotid glands, but the parotid glands are not delineated for avoidance and xerostomia has never been reported as an adverse effect. Minimizing the toxic effects in patients receiving palliative treatments, such as WBRT, is crucial. Objective: To assess whether xerostomia is a toxic effect of WBRT. Design, Setting, and Participants: This observational cohort study enrolled patients from November 2, 2015, to March 20, 2018, at 1 academic center (University of North Carolina Hospitals) and 2 affiliated community hospitals (High Point Regional Hospital and University of North Carolina Rex Hospital). Adult patients (n = 100) receiving WBRT for the treatment or prophylaxis of brain metastases were enrolled. Patients who had substantial baseline xerostomia or did not complete WBRT or at least 1 postbaseline questionnaire were prospectively excluded from analysis and follow-up. Patients received 3-dimensional WBRT using opposed lateral fields covering the skull and the C1 or C2 vertebra. Per standard practice, the parotid glands were not prospectively delineated. Main Outcomes and Measures: Patients completed the University of Michigan Xerostomia Questionnaire and a 4-point bother score at baseline, immediately after WBRT, at 1 month, at 3 months, and at 6 months. The primary end point was the 1-month xerostomia score, with a hypothesized worsening score of 10 points from baseline. Results: Of the 100 patients enrolled, 73 (73%) were eligible for analysis and 55 (55%) were evaluable at 1 month. The 73 patients included 43 women (59%) and 30 men (41%) with a median (range) age of 61 (23-88) years. The median volume of parotid receiving at least 20 Gy (V20Gy) was 47%. The mean xerostomia score was 7 points at baseline and was statistically significantly higher at each assessment period, including 21 points immediately after WBRT (95% CI, 16-26; P < .001), 23 points (95% CI, 16-30; P < .001) at 1 month, 21 points (95% CI, 13-28; P < .001) at 3 months, and 14 points (95% CI, 7-21; P = .03) at 6 months. At 1 month, the xerostomia score increased by 20 points or more in 19 patients (35%). The xerostomia score at 1 month was associated with parotid dose as a continuous variable and was 35 points in patients with parotid V20Gy of 47% or greater, compared with only 9 points in patients with parotid V20Gy less than 47% (P < .001). The proportion of patients who self-reported to be bothered quite a bit or bothered very much by xerostomia at 1 month was 50% in those with parotid V20Gy of 47% or greater, compared with only 4% in those with parotid V20Gy less than 47% (P < .001). At 3 months, this difference was 50% vs 0% (P = .001). Xerostomia was not associated with medication use. Conclusions and Relevance: Clinically significant xerostomia occurred by the end of WBRT, appeared to be persistent, and appeared to be associated with parotid dose. The findings from this study suggest that the parotid glands should be delineated for avoidance to minimize these toxic effects in patients who undergo WBRT and often do not survive long enough for salivary recovery.

Assessment of SS-A and SS-B in parotid saliva of patients with Sjögren's syndrome.

BACKGROUND: The purpose of this study was to compare the sensitivity of parotid saliva to that of serum in detecting anti-SSA/Ro and anti-SSB/La autoantibodies in patients with Sjögren's syndrome. METHODS: Forty patients and 20 controls participated in the study; all patients met the 1993 European Community criteria for the diagnosis of Sjögren's syndrome. Healthy controls were age- and sex-matched individuals with no signs or symptoms of Sjögren's syndrome. Serum and saliva samples were evaluated using AffiniTech SSA/Ro and SSB/La antibodies kits (AffiniTech, Ltd. Bentonville, AR, USA). The results were also compared with serological status of SS-A and SS-B as reported by an independent clinical laboratory. RESULTS: Serum was significantly more sensitive than saliva in detecting SSA/Ro and SSB/La antibodies (P = 0.001). There was high agreement between the results with the AffiniTech kits and the independent laboratory (kappa = 0.80; P < 0.001). However, there was poor agreement between saliva and serum results (kappa = 0.174; P = 0.168). CONCLUSIONS: The overall results appear to support that serum analysis is effective method for evaluating the presence of SS-A and SS-B autoantibodies.