ESTRO 2020 Abstract book

S402 ESTRO 2020

follow up. As per modulated RT failure patterns 40% had Type A or C and 10% had type B or D indicating marginal failures. ART volume change beyond 50% indicated 90% chance of Hopkins score 1-2 at 1 st follow up PETCT. All P16 positive patients had Hopkins score 1-2 in 1 st follow up and remained disease free till last follow up. The acute grade 2 mucositis and dysphagia were 70% and 90% respectively with 40% grade 3 dysphagia. Beyond 3 months tube dependency rates were 10% mostly beyond 70 years. 20% had haematological grade 2 plus toxicity with 3 weekly cisplatin. Conclusion This single Institution uniform adaptive modulated SIB CRT protocol shows promising early clinical results. It revalidates need of ART and documenting PETCT response score and modulated RT failure patterns. Future large cohort prospective documentation with longer follow up would answer concerns related to disease control and quality of life. PD-0661 Retropharyngeal Lymphadenopathy in Oropharyngeal Cancers:impact on distant metastasis and survival Z. Iyizoba-Ebozue 1 , L. Murray 1 , M. Arunsingh 1 , K. Dyker 1 , S. Vaidyanathan 2 , A. Scarsbrook 2 , R. Prestwich 1 1 Leeds Cancer Centre, Oncology, Leeds, United Kingdom ; 2 Leeds Teaching Hospital Trust, Radiology, Leeds, United Kingdom Purpose or Objective The influence of retropharyngeal lymph node (RPLN) involvement on prognosis in oropharyngeal carcinoma remains poorly defined. The aim was to assess the impact of RPLN involvement upon outcomes. Material and Methods Single centre retrospective analysis of 402 patients with oropharyngeal carcinoma treated non-surgically between 2010-2017. All had a baseline PET-CT and contrast- enhanced MRI and/or CT. RPLN status was determined by radiology review of cases with reported abnormal RPLN. Multivariate backwards logistic regression was used to examine impact on outcomes of factors including age, sex, T and N stage, use of concurrent chemotherapy, smoking status and presence of RPLN. Results The cohort consisted of 402 patients. Median follow up was 42.9 months. Abnormal RPLNs were identified in 10% of patients. RP LN involvement was associated with inferior 3-year outcomes for overall survival (OS) (67.1% versus 79.1%, p=0.006), distant metastases-free survival (DMFS) (73.9% versus 88.0%, p=0.011), with no significant difference in local control (81.6% versus 87.7%, p=0.154) or regional control (80.7% versus 85.4%, p=0.252). On multivariate analysis abnormal RPLN, no concurrent chemotherapy and ongoing smoking were associated with inferior DMFS and OS, while advanced T stage was also associated with inferior OS. 226/402 (56.2%) patients had p16 status available. 21/192 (10.9%) of patients with known p16 positive tumours had abnormal RP LN; in this subgroup patients with RP LN involvement had inferior outcomes but differences were non-significant (OS 77.4% versus 86.5%, p=0.059, DMFS 83.2% versus 92.3%, p=0.214). Conclusion RPLN involvement was an independent prognostic factor for the development of distant disease failure translating into inferior OS.

PD-0662 Can PNI and BMI predict severe radiation induced toxicities in Head and Neck cancer? G. Fanetti 1 , V. Lupato 2 , J. Polesel 1 , C. Gobitti 1 , E. Minatel 1 , F. Matrone 1 , A. Revelant 1 , A. Caroli 1 , F. Elisabetta 3 , V. Giacomarra 2 , E. Vaccher 4 , G. Franchin 1 1 Centro di Riferimento Oncologico CRO di Aviano- IRCCS- National Cancer Institute, Division of Radiation Oncology, Aviano, Italy ; 2 General Hospital “S. Maria degli Angeli”, Unit of Otolaryngology, Pordenone, Italy ; 3 Centro di Riferimento Oncologico CRO di Aviano- IRCCS- National Cancer Institute, Division of Immunopathology and Cancer Biomarkers, Aviano, Italy ; 4 Centro di Riferimento Oncologico CRO di Aviano- IRCCS- National Cancer Institute, Division of Medical Oncology and Immune-related Tumors, Aviano, Italy Purpose or Objective Nutritional status is part of the multidisciplinary evaluation for patients with head and neck cancer (HNCa) treated with definitive chemo‐radiotherapy. Malnutrition and weight loss decrease compliance to treatment, worse toxicity and cause cure discontinuation. No optimal nutritional biomarker to predict higher grade of toxicity is available. Body Mass Index (BMI) is a first level parameter to evaluate the nutritional status. Recent reports highlighted the possible role for Prognostic Nutritional Index (PNI) to predict outcome and toxicity in various neoplasms. The aim of our study is to evaluate the predictive role of PNI and BMI for acute and late severe toxicity. Material and Methods A retrospective analysis of 178 patients affected with HNCa and treated with chemotherapy and Intensity Modulated RadioTherapy (IMRT) at Centro di Riferimento Oncologico, Aviano was performed. Inclusion criteria were: age > 18 years, histologic HNCa diagnosis, baseline assessment of serum Albumin, Lymphocyte count, height and weight. Toxicity was recorded according to CTCAE classification. Acute toxicity was collected during IMRT and within first follow up at 3 months after IMRT and was considered severe if G3-4. Late toxicity was recorded in the subsequent follow ups and was considered severe if ≥G2. PNI was calculated according to Onodera’s formula and it was categorized as low and high PNI according to median value (ie, 50); low, normal, high and very high BMI were defined according to standard cut-points (ie, 18.5‐ 25‐30 kg/m 2 ). The comparison between groups was made with Chi square or Fisher exact test. Logistic regression and non‐parametric Kaplan Meier method evaluated the impact on toxicities of PNI e BMI. Results At least one G3‐4 acute toxicity was found in 110 out of 178 patients and 74 further developed a G2 or higher late toxicity. Alcohol consumption and primary tumor site were associated with severe late toxicity (p=0.001 and p=0.007, respectively). BMI was not associated with higher grade of toxicity. Higher PNI median value was found in patients with late Dysphagia≥G2 (p=0.016) and late Dysgeusia≥G2 (p=0.040). Univariate logistic regression model showed a relation between PNI with the incidence of late toxicity in general and hypothyroidism in particular (p=0.043 and p=0.007, respectively). At the multivariate logistic regression, PNI confirmed a relation with the incidence of late toxicity in general. Conclusion In our cohort, PNI was higher in patients with severe late dysgeusia and dysphagia while BMI was not associated with any acute or late toxicity. The risk of late toxicity increases with increasing values of PNI.