ESTRO 2020 Abstract book

S631 ESTRO 2020

paraoxonase-1 (PON1), an antioxidant enzyme. The main objective of the project was to investigate changes in PON1 concentrations and activities, before and one month after NRCT administration in RC patients Material and Methods Thirty-two patients with locally advanced RC had been included in the study between 2014 and 2018. Blood samples were collected before and one month after NRCT. PON1 serum concentration was determined, as well as, PON and arylesterase activities. All statistical calculations and graph representations were performed with the statistical package for social sciences (SPSS 22.0, Chicago, IL, USA) and GraphPad Prism 6.01 (GraphPad Software, San Diego, CA, USA). Results When compared to healthy controls, PON1 concentration was decreased significantly in patients with RC and it increased one month after receiving the NRCT. Arylesterase activity was also decreased in patients with cancer and further decreased after the treatment. Conversely, PON activity was increased in cancer patients and, showed a non-significant trend to decrease after NRCT (figure 1). Moreover, PON1 concentration and its specific activities were able to differentiate patients with clinical nodal stages N1 and N2 diagnosis

Conclusion NRCT is able to modify the PON1-related variables in RC patients. One month after NRCT, values of PON1 concentration and enzymatic specific activities are able to return to similar values to those in control individuals. Moreover PON1 concentration and its specific activities could help in the diagnosis of clinical nodal stage. PO-1105 Interstitial PDR brachytherapy for the treatment of squamous cell anal carcinoma R. Bourdais 1 , S. Achkar 1 , T. Kumar 1 , M. Kissel 1 , M.H. Ta 1 , F.A. Pounou Kamga 1 , W. Boukhelif 2 , J. Durand-Labrunie 1 , C. Haie-Meder 1 , C. Chargari 1 1 Gustave Roussy, Radiothérapie, Villejuif, France ; 2 Centre Hospitalier Intercommunal de Créteil, Radiothérapie, Créteil, France Purpose or Objective To examine the outcome of patients treated with interstitial pulsed-dose-rate brachytherapy (PDR-BT) for boosting the residual tumor after external radiotherapy for an anal squamous cell carcinoma. Material and Methods Medical records of patients receiving a brachytherapy boost after radiotherapy for squamous cell anal carcinoma in our Institute between 2008 and 2019 were retrospectively reviewed. After receiving pelvic irradiation +/- concurrent chemotherapy, patients were delivered a

Conclusion Results obtained in this study show clear alterations in glycolysis, citric acid cycle and amino acid metabolism in RC patients. Significant differences between the control and cancer groups were observed in the plasma concentrations of many metabolites. Lactate, fumarate and glutamine values returned to similar levels to those of the control group after NRCT, meaning that the NRCT is also able to modify the metabolic profile of RC patients. PO-1104 Effect Of Neoadjuvant Radiochemotherapy On Activity Of Paraoxonase -1 In Rectal Cancer Patients E. Rodríguez 1,2 , J. Gomez 1 , A. Moreno 2 , J. Acosta 1 , L. Torres 1 , J. Trilla 1 , Y. López 1 , G. Baiges 2 , A. Hernández 2 , J. Camps 2 , J. Joven 2 , M. Arenas 1,2 1 Hospital Universitari Sant Joan de Reus, Department of Radiation Oncology, Reus, Spain ; 2 Institut d’Investigació Sanitària Pere Virgili- Universitat Rovira i Virgili, Unitat de Recerca Biomèdica, Reus, Spain Purpose or Objective Standard treatment for stage II and III rectal cancer (RC) is neoadjuvant or preoperatively radiochemotherapy (NRCT) followed by surgery. However, little is known about the effects produced by this oncological therapy on