Title: 1218 - Radiotherapy Related to Salivary Protein Content in Oral Cancer
maria gonzalez (Presenter)
King's College London Dental Institute
Guy Carpenter, King's College London Dental Institute
Sophie Bozorgi, King's College London Dental Institute
Garrit Koller, King's College London Dental Institute
Timothy Watson, King's College London Dental Institute
Kenneth Bruce, King's College London
Avijit Banerjee, King's College London Dental Institute
Objectives: Objective Intensity-modulated radiotherapy (IMRT) was developed to mitigate/reduce the adverse side-effects, including salivary gland dysfunction, of treatment for head-and-neck cancer (H&NCa). The null hypothesis of this longitudinal and cross-sectional study was there is no correlation between IMRT-induced changes in salivary proteins with caries and salivary gland hypofunction.
Methods: Unstimulated whole mouth saliva samples were obtained from 40 patients diagnosed with H&NCa at a tertiary regional centre, recruited and consented pre- and post-IMRT (allocated in two groups). Age/gender-matched volunteers were used as healthy controls. The saliva samples were used to quantify flow-rate, protein concentration and specific ELISA assays for IgA, cystatinS, and albumin. Alpha-amylase activities were determined kinetically and all markers correlated to the clinical parameters of IMRT dose, duration, radiation field and caries experience (DMFT/DMFs). Statistical analysis was carried out using two-tailed t-test and ANOVA; significance, after testing for normality, was set p<0.05 (GraphPad7).
Results: Significant reductions in unstimulated flow-rate and overall protein output were identified for individuals on IMRT as compared to healthy controls and before IMRT. However, total protein concentration and specifically the proteins MUC5B and albumin were significantly increased. Conversely, MUC7, IgA, CystatinS were statistically decreased post-IMRT compared to healthy controls, whereas α-amylase reduction was underpowered to assess significance. MUC5B and MUC7 concentration were increased (NS) after 6-months of IMRT compared to pre-IMRT, α-amylase reduction was significant in this group. The mean caries experience (DMFT/DMFs) was increased significantly for individuals on IMRT (12-months) compared to healthy controls. However, pre-IMRT caries experience were higher than after 6-months of IMRT. The null hypothesis was rejected.
Conclusions: Agreeing with previous studies examining conventional RT-regimes, IMRT resulted in decreased flow-rate and salivary protein composition. Specific changes in salivary proteins and activity were observed. This data demonstrates specific alterations of mucin concentration, providing potential insights into radiation-associated changes and therapeutic approaches.
This abstract is based on research that was funded entirely or partially by an outside source:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE