ESTRO 2021 Abstract Book

S843

ESTRO 2021

Conclusion The association between objective test outcomes and PROs is weak, indicating that these outcome measures provide different information about oral functioning in patients with HNC. It is therefore important to measure oral related problems both objectively and subjectively. This will acquire unique information and will help create the complete picture of a patients’ perspective and functioning. PO-1014 Prognosis classifier for elderly head-and-neck squamous cell carcinoma patients A. Rühle 1 , C. Stromberger 2 , E. Haehl 1 , C. Senger 2 , A.E. Falkenstein 1 , R. Stoian 1 , C. Zamboglou 1 , A. Knopf 3 , A. Grosu 1 , N. Nicolay 1 1 University Medical Center Freiburg, Department of Radiation Oncology, Freiburg, Germany; 2 Charité - Universitätsmedizin Berlin, Department of Radiation Oncology, Berlin, Germany; 3 University Medical Center Freiburg, Department of Otorhinolaryngology, Freiburg, Germany Purpose or Objective The treatment of elderly head-and-neck squamous cell carcinoma (HNSCC) patients is challenging, as this population was either excluded or is underrepresented in the landmark trials defining the current standard treatment. Overall survival (OS) of this patient population is often compromised due to underlying comorbidities and the advanced age itself. Prognosis classifiers such as scores and survival nomograms could therefore support clinicians deciding between curative or palliative treatments. Materials and Methods 284 HNSCC patients aged ≥65 years undergoing curative (chemo)radiation at a tertiary cancer center were used for the creation of a survival score. Using a backward multivariate Cox regression analysis including both clinical and pathological parameters, point values were given for the significant parameters according to their beta regression values. Subsequently, the survival score was validated in an external cohort consisting of 217 elderly HNSCC patients undergoing curative (chemo)radiation at another tertiary cancer center. A nomogram was developed for 2-year and 4-year OS estimation on the basis of the cumulative data of both cohorts using concordance statistics as measure of goodness-of-fit of the model. Finally, we checked whether the survival score was able to predict the prognosis of elderly HNSCC patients treated by primary surgery without adjuvant (chemo)radiation (n=169). Results The Karnofsky Performance Status (KPS, HR=2.654, p <0.001), the age-adjusted Charlson Comorbidity Index (CCI, HR=2.598, p <0.001) and the baseline C-reactive protein concentration (CRP, HR=1.634, p =0.064) were prognostic parameters for OS in the multivariate Cox regression with p <0.1 as inclusion value. Based on the beta regression values, KPS ≤70%, CCI ≥6 points and CRP concentration ≥5 mg/L was given 1 point, 1 point and 0.5 points, respectively. The median OS of the development cohort amounted to 107 (0 points), 34 (0.5 points), 28 (1 point), 11 (1.5 points), 9 (2 points) and 6 months (2.5 points), respectively ( p <0.001, log-rank test). Combination of the different groups into three main prognosis groups resulted in a favorable (0 points, 107 months), an intermediate (0.5-2 points, 28 months) and a poor (2.5 points, 6 months) subgroup ( p <0.001). The survival score also discriminated the OS in the external validation group: Here, the OS ranged at 130, 29 and 9 months for the favorable, intermediate and poor group, respectively ( p =0.005). The derived nomogram for the 2-year and 4-year OS showed a concordance index of 0.65 (Harrell’s C). However, in the surgery alone group, neither CCI ≥6 points (HR=1.937, p =0.232) nor baseline CRP concentration ≥5 mg/L (HR=1.743, p =0.328) were significant prognostic parameters. Conclusion We created and externally validated a prognosis classifier for elderly HNSCC patients undergoing chemoradiation. The fact that only three clinically easily assessable parameters are required for the score is a main advantage for the clinical routine.

PO-1015 Prospective evaluation of anatomical changes of salivary glands during MRI-guided ART for HNC J. van Timmeren 1 , M. Bogowicz 1 , M. Chamberlain 1 , S. Ehrbar 1 , R. Dal Bello 1 , H. Garcia Schüler 1 , J. Krayenbuehl 1 , L. Wilke 1 , N. Andratschke 1 , M. Guckenberger 1 , S. Tanadini-Lang 1 , P. Balermpas 1