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.
Results
One hundred and forty-two PG saliva samples from 26 patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated saliva showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated saliva alone had elevated LF secretion rate and beta-2-microglobulin (B2 M) concentration with decreased calcium (Ca2+ ) and magnesium (Mg2+ ) concentrations and Ca2+ secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg2+ and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K+ ) and Mg2+ 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 Ca2+ secretion rate was found.