ESTRO 2020 Abstract book

S403 ESTRO 2020

could be a promising reliable index for optimizing the consolidate treatment and follow‐up interval after the treatment. PD-0664 Outcome and toxicity of RT in elderly HNSCC patients –experience from a large monocentric cohort E. Haehl 1 , A. Rühle 1 , H. David 1 , T. Von Kalckreuth 1 , T. Sprave 1 , A. Knopf 2 , A.L. Grosu 1 , N.H. Nicolay 1 1 Medical Center – University of Freiburg, Department of Radiation Oncology, Freiburg, Germany ; 2 Medical Center Purpose or Objective Head‐and‐neck cancer is one of the most common malignancies globally. 25% of patients diagnosed with head‐and‐neck cancer are older than 70 years, with a further increase in elderly patients prognosticated. Underrepresentation in clinical trials, a higher burden of comorbidities and different weighing of the maintenance of quality of life versus survival benefit challenge clinical decision making for this cohort and largely lack clinical evidence. Material and Methods We retrospectively analyzed demographic parameters, outcomes and treatment‐related toxicities of all elderly patients (>65 years) treated with definitive or adjuvant (chemo)radiotherapy for histologically confirmed HNSCC between 2010 and 2018 at the Department of Radiation Oncology of the Freiburg University Medical Center. IMRT was administered to a total dose of 70Gy for definitive treatments and 60‐66Gy for adjuvant treatments according to institutional guidelines. Concurrent chemotherapy was scheduled for all patients undergoing definitive treatment and in case of incomplete resection or ECS in the adjuvant setting. Results 246 predominantly male (69.1%) patients with a median age of 72 years (65‐96) were identified. Affected tumour sites were oropharynx (32%), oral cavity (23%), larynx (17%) and hypopharynx (12%). 166 (67%) patients received definitive treatment with (chemo‐)radiotherapy, and 80 (33%) were irradiated in an adjuvant setting. Radiotherapy was completed in 85% of primary and 90% of adjuvant patients, and median doses were 62Gy and 67.8Gy, respectively. 147 (60%) patients started concomitant chemotherapy with a completion rate of 74%. 2‐year rates for overall survival, progression‐free survival and loco‐ regional control were 56.9%, 44.9% and 75.5%, respectively. Overall survival and progression‐free‐survival differed significantly between age groups with a median of 40 and 23 months in patients aged 65‐74 years and 22 and 12 months in those 75 years and older, respectively (overall survival: p=0.012 / progression‐free survival: p=0.039). Completion of concomitant chemotherapy resulted in a trend towards improved median survival of 7 months in patients aged 65‐74 years (p=0.107), and in no significant effect in older patients (p=0.67). Karnofsky performance status was the strongest independent prognostic factor regarding overall survival (HR=0.387; 95% CI 0.23‐0.64; p<0.01). 66% of patients experienced any acute grade 3 (CTCAE) toxicity, with 59% and 12% of patients developing grade 1‐2 and grade 3 chronic toxicities, respectively. Conclusion Radiotherapy is a feasible therapy option for elderly patients with moderate chronic toxicities albeit substantial acute toxicities. High loco‐regional control rates compared to overall survival and the prognostic value – University of Freiburg, Department of Otorhinolaryngology, Freiburg, Germany

PD-0663 The trend of neutrophil-to-lymphocyte ratio as a predictor of prognosis to nasopharyngeal carcinoma P. Yang 1 , Y. Zhao 2 , A. Mohamed 3 , H. Liang 1 , C. Chen 1 , Y. Xu 4 , C. Nantavithya 5 , D. Kannarunimit 5 , Y. Shi 1 , H. Wang 1 , H. Jin 1 1 Hunan Cancer Hospital- the Affiliated Cancer Hospital of Xiangya Medical School- Central South University, Head and Neck Radiotherapy Department, ChangSha, China ; 2 Unity Hospital- Rochester Regional Health, Internal Medicine, Rochester, USA ; 3 University of Texas- MD Anderson Cancer Center, Radiation Oncology, Texas, USA ; 4 Zhejiang Cancer Hospital, Thoracic Radiotherapy Department, Hangzhou, China ; 5 King Chulalongkorn Memorial Hospital, Radiotherapy Department, Bangkok, Thailand Purpose or Objective The association between pre‐treatment neutrophil‐ lymphocyte ratio (NLR) with adverse prognoses was reported for multiple tumor types. Several studies have also investigated the potential prognostic value of NLR in nasopharyngeal carcinoma (NPC) patients, but the results were inconsistent. Furthermore, collecting NLR only once before treatment can be affected by many factors, causing the heterogenous unreliable results. Moreover, induction chemotherapy and the immune regulation drugs commonly alter NLR before radiotherapy, which might compromise the conclusion. Thus, we aim to evaluate the prognostic value of NLRs (NLR‐trend) during the whole radiotherapy in the absence of chemotherapy and immune regulation era NPC patients in Nasopharyngeal Carcinoma patients. Material and Methods We selected NPC patients with definitive radiotherapy retrospectively from a cohort examining long‐term cancer outcomes between 1992 and 2005. Individual NLRs were continuously collected through complete blood count (CBC) of pretreatment and radiotherapy period. NLRs of each patient was fitted by the line model, and the gradient of each line was calculated for NLR‐trend evaluation. Patients were divided into the low‐trend group (under median gradient value) and high‐trend group (greater than or equal to median gradient value). Kaplan–Meier method and log‐rank test were used to calculate and compare survival outcomes of overall survival (OS), disease‐free survival (DFS), distant metastasis‐free survival (DMFS), and locoregional recurrence‐free survival (LRFS). Multivariable Cox regression analyses were performed to assess the association between NLR and 3‐year and 5‐year OS. Results We finally enrolled 528 consecutive NPC patients according to inclusion criteria. Ninety‐six percent of them are locally advanced or metastasized, and the median age was 46 (18‐77). The median gradient of NLR‐trend was 0.8, which was the cutoff value for grouping. No association was found between NLR‐ trend and T‐status, N‐status or M‐status. The patients with high NLR‐trend (gradient ≧ 0.8) was significant lower than the ones with low NLR‐trend (gradient<0.8) in 3‐year OS ( p=0.042), while NLR‐trend was not associated with 5‐year OS ( p=0.054). At 5 years, high NLR‐trend (gradient ≧ 0.8) predicted worse LRFS ( p=0.034) and DFS ( p=0.018), but NLR‐trend was not correlated with DMFS. The results of a multivariate analysis revealed that NLR‐trend independently predicts OS of 3‐year ( p=0.027) and 5‐year ( p=0.023). Conclusion Higher‐gradient NLR‐trend is an independent poor prognostic factor of NPC patients with radiotherapy. NLR should be monitored dynamically during treatment, which