ESTRO 2022 - Abstract Book

S955

Abstract book

ESTRO 2022

to severe dry mouth during the day, while only 22 patients had moderate to severe dry mouth during night (p= 0.04).Forty five patients had to drink more water during day due to dry mouth, while only 22 patients had to drink more water during night (p=0.0005). Nineteen patients had sticky saliva during day time, while only 9 patients had it during night time (p=0.04).VMAT technique, time gap of more than 1 year post radiotherapy treatment, lower contralateral parotid and submandibular gland doses were associated with lesser xerostomia. Concurrent chemotherapy, intent of treatment, tobacco use had no significant impact on xerostomia. There is diurnal variation in xerostomia with day time xerostomia being more common than night time xerostomia. Use of IMRT or VMAT with sparing of contralateral parotid and submandibular doses should be advocated for all cases of head and neck cancer patients whenever feasible. Conclusion Xerostomia and diurnal variation can be significantly reduced by VMAT.Radiation doses to parotids and submandibular glands predominantly determine the degree of diurnal variation.We need to evaluate this in larger cohort and at baseline and at multiple time points post radiotherapy to understand impact of radiation on xerostomia in a better detailed way. F. Beghella Bartoli 1 , A. Nardangeli 1 , S. Chiesa 1 , C. Mazzarella 1 , F.M. Topa 1 , E. Lepre 1 , A. Martino 1 , S. Bracci 2 , M.C. Cannatà 2 , G.M. Della Pepa 3 , L. Dinapoli 4 , G.F. Colloca 1 , S. Longo 1 , M. Massaccesi 1 , A. Olivi 3,5 , M.A. Gambacorta 1,6 , V. Valentini 7,1 , M. Balducci 1,7 1 Fondazione Policlinico Universitario A. Gemelli IRCCS, UOC di Radioterapia Oncologica, Dipartimento Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, Rome, Italy; 2 Fondazione Policlinico Universitario A. Gemelli IRCCS,, UOC di Radioterapia Oncologica, Dipartimento Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, Rome, Italy; 3 Fondazione Policlinico Universitario A. Gemelli IRCCS, Istituto di Neurochirurgia, Rome, Italy; 4 Fondazione Policlinico Universitario A. Gemelli IRCCS, UOS Psicologia Clinica, Rome, Italy; 5 Università Cattolica del Sacro Cuore, Istituto di Neurochirurgia, Rome, Italy; 6 Università Cattolica del Sacro Cuore,, Istituto di Radiologia, Rome, Italy; 7 Università Cattolica del Sacro Cuore, Istituto di Radiologia, Rome, Italy Purpose or Objective Pseudoprogression is still a challenging issue in clinical practice, occurring in about 20% of high-grade glioma patients treated with adjuvant radiation plus temozolomide (TMZ). 1 Pathological confirmation is the gold standard for the diagnosis of pseudoprogression but it is not often applicable, and it may take several months before pseudoprogression can be clearly distinguished from early tumor progression on follow-up imaging. The therapeutic approach is usually to continue with the adjuvant TMZ. According to our institutional experience in taking advantage of chemosensitive effect of low dose fractionated radiotherapy in Glioblastoma Multiforme (GBM) 2-3-4 at recurrence or at diagnosis with poor prognosis, we explored the safety and efficacy of low-dose radiotherapy plus temozolomide in patients with GBM with evidence of pseudoprogression after radiochemotherapy . Materials and Methods Patients affected by GBM previously treated by primary standard radiochemotherapy with evidence of pseudoprogression during adiuvant chemotherapy with temozolomide were enrolled. Radiologically, pseudoprogression was defined as a new or enlarging area(s) of contrast agent enhancement, in the absence of true tumor growth. Low dose radiotherapy (0.60 Gy twice daily over 5 days, every 28 days) with concurrent temozolomide for two cycles was administered. Primary endpoints were toxicity, progression free survival (PFS) and overall survival (OS). Results A total of twenty-seven patients were enrolled from January 2018 to August 2020. Acute hematologic toxicity G1-G2 was observed in 6 patients (22.2%) and G3 in 1 patient (3.7%). No acute neurological toxicity was detected. Two patients (7.4%) had partial response after low-dose radiotherapy while stable disease was registered in 10 patients (37%) for at least 8 weeks. Fifteen patients experienced progressive disease (55.6%). With a median FUP of 20 (range 4-35 months), the median OS was 15 months with a 1-year OS of 61.3%, while the median PFS was 9 months with a 1-year PFS rate of 36%. Conclusion Low-dose radiotherapy with concomitant temozolomide was well tolerated and could be useful in continuing the use of the first-line chemotherapy in patients with pseudoprogression, reserving the shift to a second line of chemotherapy only for those patients with a progression disease. 1. Kruser TJ, et al. Pseudoprogression after glioma therapy: a comprehensive review. Expert Rev Neurother. 2013;13(4):389–403. 2. Balducci M, et al. Low-dose fractionated radiotherapy and concomitant chemotherapy in glioblastoma multiforme with poor prognosis: a feasibility study. Neuro Oncol. 2012;14(1):79-86. 3. Balducci M, et al. Low-dose fractionated radiotherapy and concomitant chemotherapy for recurrent or progressive glioblastoma: final report of a pilot study. Strahlenther Onkol . 2014;190(4):370-376. 4. Chiesa S. et al. Hypofractionated and Low dose radiotherapty combined with Temozolamide in naïve unresectable glioblastoma: a pilot Study. Poster (digital): CNS PO-1123 Unconventional treatment in GBM with pseudoprogression: low-dose radiotherapy could be an option?