ESTRO 38 Abstract book

S132 ESTRO 38

From Aug 2016 to Aug 2018, 109 HNCS were enrolled. Ninety-one were eligible for analysis and randomized to intervention (n=55) or control (n=36) (Table 1). Median age was 61 years (range 34-80). Oropharynx was the predominant tumor location (95%). Prescribed treatment dose was 66-68 Gy. Sialometry showed an increase in mean salivary flow from unstimulated 0.15 ml/min to stimulated 0.57 ml/min (ΔSaliva 0.42 ml/min) for the intervention group (p < 0.0001) (Fig. 1). Viscosity on the IPT showed that the transit time of saliva at 5 cm was significantly faster for the stimulated saliva output (3 sec) compared to the unstimulated output (21 sec) for the intervention group (p = 0.02) (Fig. 1). For the control group, mean salivary flow also increased with chewing gum stimulation (ΔSaliva 0.56 ml/min, p<0.001) and saliva transit time for viscosity improved from 15 to 4 sec (p=0.06). No significant difference was seen between the unstimulated and stimulated mean salivary flow when comparing the two groups. The GRIX questionnaire showed improved QOL for the intervention group for items concerning xerostomia during the day (Q2, p=0.001), xerostomia when being outdoor (Q3, p=0.001) and while eating (Q4, p=0.004).

0.375 (RSI >0.375 =radioresistant). In comparison to cohorts of other histologies including bladder transitional cell carcinoma, glioma, cervical SCC, esophageal adenocarcinoma, melanoma, non-melanoma skin cancer, non-oropharynx and oropharynx head and neck SCC, PeSCC is one of the most intrinsically radioresistant cancers. Genomically, PeSCC is significantly more radioresistant while comparing with oropharynx head and neck SCC ( p =0.01) and cervical SCC ( p =0.002). The PeSCC GARD values ranged from 9.56 to 38.39 (median 18.25), suggesting various radiation therapeutic effects if treated with a uniform PORT dose of 50 Gy. GARD-modeled dose of 50 Gy controls only 52% of PeSCC lesions. Median follow- up from the completion of RT for the clinical cohort was 12.1 months. The majority of patients presented with pathological N2 or N3 disease (n=15; 83%) and treated with adjuvant concurrent platinum-based chemoradiotherapy (CRT, n=16; 89%). Nine out of the 18 patients had locoregional recurrence (LRR). Of whom, 6 patients presented with LRR within six months since completion of PORT. Conclusion The majority of PeSCC are intrinsically radioresistant with low GARD-based radiation therapeutic effect. This finding is consistent with the observed high rate of LRR (50%) in the clinical cohort treated with PORT doses of 45-59.4 Gy. A GARD-based strategy may help personalize radiation therapy dose prescription to individual tumor biology and improve outcomes. OC-0269 A randomized phase III trial for alleviating radiation-induced xerostomia with chewing gum J.K. Kaae 1,2 , L. Stenfeldt 1 , B. Hyrup 3 , C. Brink 2,4 , J.G. Eriksen 5 1 Odense University Hospital, Oncology, Odense, Denmark; 2 University of Southern Denmark, Clinical Research, Odense, Denmark ; 3 Fertin Pharma A/S, Fertin Pharma, Vejle, Denmark ; 4 Odense University Hospital, Laboratory of Radiation Physics, Odense, Denmark; 5 Aarhus University Hospital, Experimental Clinical Oncology, Aarhus, Denmark Purpose or Objective Radiation-induced xerostomia is a serious problem affecting quality of life (QOL) after radiotherapy (RT) for head and neck cancer. The aim of this study was to assess the effect of tasteless chewing gum to improve salivary flow after radiation-induced xerostomia for Head and Neck Cancer Survivors (HNCS). Material and Methods HNCS treated with curative intended primary RT and without loco-regional failure were recruited from the follow-up clinic. Inclusion criteria were subjective feeling of xerostomia as rated by the DAHANCA score, sufficient dental health, and minimum six months follow-up after end of RT. HNCS were randomized 2:1 to one month of daily chewing gum or best supportive care. Intervention was a customized experimental sugar-free chewing gum without flavors. Unstimulated and stimulated sialometry were performed to measure saliva flow. Saliva viscosity was tested with the Inclined Plane Test (IPT) by recording the saliva transit time on a 20 cm vertical plate with cutoff at 5 cm. The validated Groningen Radiotherapy-Induced Xerostomia (GRIX) questionnaire was completed to evaluate the subjective QOL in relation to xerostomia. The primary endpoint was the difference in salivary flow rate between unstimulated and stimulated sialometry after using chewing gum for one month. Results Proffered Papers: CL 5: Proffered papers : Randomised Clinical Trials

Conclusion Customized experimental chewing gum was able to increase salivary flow and decrease viscosity for Head and Neck Cancer Survivors experiencing radiation-induced xerostomia for both the intervention and control group. Xerostomia-related QOL only improved for the intervention group. OC-0270 Antihormones with or without irradiation in breast cancer: 10-year results of the ABCSG 8A trial G. Fastner 1 , F. Sedlmayer 1 , J. Widder 2 , M. Metz 3 , H. Geinitz 4 , K. Kapp 5 , L. Sölkner 6 , R. Greil 7 , R. Jakesz 8 , W.