The effect of parotid gland-sparing IMRT on salivary composition, flow rate and xerostomia measures.

The effect of parotid gland-sparing IMRT on salivary composition, flow rate and xerostomia measures.

Oral Dis. 2017 Apr 23;:

Authors: Richards TM, Hurley T, Grove L, Harrington KJ, Carpenter GH, Proctor GB, Nutting CM

Abstract
OBJECTIVES: To describe parotid gland (PG) saliva organic and inorganic composition and flow rate changes, after curative intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC) and analyse the relationship between PG saliva analytes and xerostomia measures.
METHODS AND MATERIALS: Twenty-six patients recruited to five prospective phase 2 or 3 trials which assessed toxicity and efficacy of IMRT by HNC subsite, provided longitudinal PG salivas. Salivary flow rate, subjective and objective xerostomia measures were prospectively collected and salivas tested for inorganic and organic analytes. Statistical comparisons of longitudinal analyte changes and analysis for a relationship between dichotomised xerostomia score and saliva analytes were performed.
RESULTS: One-hundred and forty-two PG saliva samples from twenty-six patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated salivas showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated salivas alone had elevated LF secretion rate and beta-2-microglobulin (B2 M) concentration with decreased Calcium (Ca(2+) ) and Magnesium (Mg(2+) ) concentrations and Ca(2+) secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg(2+) and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K(+) ) and Mg(2+) concentration. Unstimulated TP secretion rate was lower in the presence of high grade xerostomia. Otherwise, no relationship between xerostomia grade and PG salivary flow rate, TP and Ca(2+) secretion rate was found.
CONCLUSION: Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG. This article is protected by copyright. All rights reserved.

PMID: 28434191 [PubMed - as supplied by publisher]

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