ESTRO 2020 Abstract book

S14 ESTRO 2020

statistically significantly related to dermatitis in all population. PH-0044 Anaplastic thyroid carcinoma in the Netherlands, very bad but not for all! M. De Ridder 1 , E. Nieveen van Dijkum 2 , A. Engelsman 2 , K. Ellen 3 , H. Klumpen 4 , C. Rasch 1 1 LUMC, Radiation Oncology, Leiden, The Netherlands ; 2 Amsterdam UMC - Cancer Center Amsterdam, Surgery, Amsterdam, The Netherlands ; 3 LUMC, Medical Oncology, Leiden, The Netherlands ; 4 Amsterdam UMC - Cancer Center Amsterdam, Medical Oncology, Amsterdam, The Netherlands Purpose or Objective Anaplastic thyroid carcinoma (ATC) is a rare, but very aggressive type of thyroid cancer. Extensive local disease is the first presentation in most people and due to the rapid growth velocity of these tumors patients die of their local disease. Survival is known to be poor, but small series describe prolonged survival in patients treated with combined modality treatments. Material and Methods All patients with ATC between 1989-2016 were identified in the Netherlands Cancer Registry (NCR). Patient characteristics, treatment characteristics and survival was scored. Of all patients, excerpts from the pathology report were linked to gain tumor information. Standardized incidence rates were calculated, survival was estimated using the Kaplan Meier method and factors associated with survival were tested by univariable and multivariable regression model. Results In total 812 patients with ATC were included in the analyses. Mean standardized incidence rate was 0.18/100,000 (range over the years 0.11 – 0.27 / 100,000). A significant trend towards increase was found over the years with an annual percentage change of 1.3% / year (95% CI 0,4 – 2.1 %). Median overall survival was 2.2 months and estimated 1-year survival was 12%. Patients without distant metastases at time of diagnosis had an estimated 1-year survival of 21.6%. Exploratory analysis of the patients with a longer survival than 2 years showed that these patients had significantly less bilateral lymph node metastases (10% vs. 25%), less distant metastases (8% vs. 45%), underwent more often double or triple therapy (69% vs 19%) and were younger (age below 65 years 48% vs 24% (all with an p<0.001). Conclusion This is the first nationwide analysis of patients with ATC with a national coverage of the data. ATC is rare and is highly lethal with an median survival of 2.2 months and estimated 1-year survival of 12%. Major risk factor for ATC is previous well-differentiated thyroid cancer, since the incidence of thyroid cancer rose over the previous decades, the incidence rise found in our study could be linked to the overall rise in thyroid cancer. Despite the very low survival rates, there appears to be a subgroup of patients with prolonged survival. One key factor associated with prolonged survival is multimodality treatment containing surgery, radiotherapy and eventually chemotherapy. Future research will focus on a more distinctive definition of the subgroup that may benefit most from intensive treatment.

PH-0043 Age related toxicity and outcome in oropharyngeal and nasoparyngeal cancer patients E. IvaldI 1 , G. Infante 2 , N. Facchinetti 1 , P. Bossi 3 , N.A. Iacovelli 1 , A. Cavallo 4 , R. Ingargiola 1 , L.D. Locati 5 , C. Bergamini 5 , C. Resteghini 5 , L. Licitra 5 , F. Platini 5 , G. Calareso 6 , C. Fallai 1 , E. Orlandi 7 1 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Radiotherapy 2 Department, Milan, Italy ; 2 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Unit of Clinical Epidemiology and Trial Organization, Milan, Italy ; 3 ASST Spedali Civili di Brescia, University of Brescia, Brescia, Italy ; 4 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Unit of Medical Physics, Milan, Italy ; 5 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Head and Neck Medical Oncology Department, Milan, Italy ; 6 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Department of Radiology, Milan, Italy ; 7 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Radiotherapy 1-2 Department, Milan, Italy Purpose or Objective To evaluate toxicity and outcome in elderly oropharyngeal (OPC) and nasopharyngeal cancer (NPC) patients (pts) treated with intensity modulated radiation therapy (IMRT) with/without chemotherapy (CHT). Material and Methods We retrospectively analyzed a total number of 392 pts (213 OPC and 179 NPC) that underwent IMRT with/without concurrent CHT and/or induction CHT from 2006 to 2017. All patients were categorized in ≥65 years old (elderly) and <65 (younger).Overall survival (OS) and disease free survival (DFS) were estimated with Kaplan-Meier curves and compared with the log-rank test. Acute toxicity rate (> G3) according to CTCAE v4.0 was also analyzed. Baseline Epstein Barr Virus plasma Load was collected in 90% of NPC pts and human papilloma virus (HPV) status was recorded in 95% of OPC pts. We reported toxicity and outcome results for the following categories: NPC population, OPC pts and HPV positive and negative cohorts. Results OS stratified for age showed a better outcome for younger pts in OPC (HR 2.06, CI 1.14 - 3.72) and NPC population (HR 4.3, CI 1.83 - 10.09). Also in OPC HPV positive pts (HR 2.97, CI 1.2 - 7.31), mortality is greater in older pts compared to younger ones. No statistical significance in OS was found in OPC HPV negative group between younger and older pts (fig.1). Age at diagnosis seems to be statistically significantly related to the OS in all categories except in OPC HPV negative. DFS stratified for age showed a better outcome for younger pts in NPC (HR 2.85, CI 1.51 - 5.38) and OPC HPV positive population (HR 2.4, CI 1.06 - 5.44). In all groups, younger pts showed a better DFS than older, however only for NPC and OPC HPV positive pts is statistically significant (fig.2). Like the OS, age at diagnosis seems to be related to DFS in the entire cohort except for the OPC HPV negative group. Analyses performed to identify correlation between toxicities and other variables stratified for age showed that BMI (cut off 25 Kg/m2) is generally associated with toxicity only in the OPC patients, but independently of the age. In OPC population and in OPC HPV positive sub-group, gender seems to have an interaction with age even if not statistically significant. Indeed, younger men appear to have a major risk of toxicity than younger women. On the contrary, older women are more at risk than men. Old NPC pts with N2-N3 category (according to AJCC 7 edition) are more likely to develop a G3 toxicity than N0-1 pts (OR 4.48, CI 0.99 - 20.35). Age was statistically significantly related to dermatitis in both NPC (OR 2.64, CI 1.06-6.54) and OPC populations (OR 6.23, CI 1.88 - 20.67). Conclusion In conclusion, older NPC, OPC and OPC HPV positive pts showed a markedly worse survival than the younger counterparts. HPV status was confirmed to be a positive prognostic factor independently of age. Age was