S391
Clinical - CNS
ESTRO 2026
Standard postoperative treatment consists of radiation (60 Gy in 30 fractions over 6 weeks) with concomitant and adjuvant temozolomide.In elderly or poor performance status (PS) patients, hypofractionated radiotherapy (HFRT) is often used to maintain quality of life with similar efficacy as the conventional course. The most common HFRT regimen is 40 Gy in 15 fractions over 3 weeks which corresponds to a significant lower biological equivalent dose (BED) compared to the standard.We present data on glioblastoma patients that received HFRT with a total BED similar to the standard one. Material/Methods: Between May 2023 and October 2025, 26 glioblastoma patients underwent HFRT with a total dose of 52.5 Gy over 3 weeks at our institute.Inclusion criteria were age>65 or poor PS or needs for reduced access to hospital.Median age was 70 (range 54-83), median Karnofsky PS was 80 (70-100). Radical surgery was performed in 5/26 patients, a subtotal or partial resection was obtained in 13/26 patients. Eight patients were unsuitable for resection. MGMT methylation was detected in 8/26 patients and 9/26 patients had unmethylated tumors (unknown in the remaining patients). Fifteen patients underwent both concomitant and adjuvant chemotherapy with temozolomide and 11 patients just adjuvant. Low dose clinical target volume (CTV) was defined as the surgical cavity and/or macroscopic residual disease plus 1.5 cm margin and prescribed to and high dose CTV as surgical cavity and/or macroscopic residual disease plus 3-5 mm margin. Both CTVs were expanded by 2 mm to obtain low and high dose planning target volume(PTV) and prescribed to 40.05 Gy and 52.5 Gy in 15 fractions respectively, over 3 weeks with volumetric modulated arc therapy, simultaneous integrated boost and image guided radiotherapy. Results: Follow-up data were available for 24 patients. Median follow-up time was 5 months (range 1-16). All patients completed the treatment with no significant toxicities.Stable or partial response was obtained in 14 patients. In 10 patients a progression of disease was observed.At the time of data collection, 8/24 patients were died with a median survival from the end of radiation of 6 months (range 1-9). Survival>12 months was associated with younger age (median 60), and wide surgical resection. Conclusion: HFRT delivering a standard BED appears feasible, safe, and effective in elderly or frail glioblastoma patients, allowing reduced hospital access without compromising short-term efficacy. Further prospective validation with longer follow-up is warranted. References: Gregucci F et al. Poor-Prognosis Patients Affected byGlioblastoma: Retrospective Study of
also received neoadjuvant RT to investigate tissue changes. We report initial results of immunohistochemical tissue analyses and changes in biomaterial after neoadjuvant therapy in cohorts 0 and 1 of the ALA-RDT-trial. Results: Following the 3+3-trial design, 3 patients were treated in cohort 0 with two neoadjuvant fractions of RT without radiosensitization and 3 patients were treated in cohort 1 with two fractions of neoadjuvant RT of which the first was performed as RDT. Immunohistopathological analyses showed a tendency towards higher levels of Iba1 and Caspase 3 after neoadjuvant RDT when compared to standard re-RT without 5-ALA. There were no signs of liver-toxicity. The kinetics of soluble 5-ALA metabolites of PPIX in peripheral blood and CPI/III in urine4 was not different between the cohorts, suggesting no cumulative effects of oral 5-ALA application. Treatment was tolerated well without dose-limiting toxicity; the trial is proceeding with the dose escalation phase, having not yet reached a maximum tolerated dose. Conclusion: RDT using 5-ALA as a radiosensitizer precursor within standard re-RT in patients with recurrent GBM appears to be safe and well tolerated. References: 1: Pepper NB, Stummer W, Eich HT. Strahlenther Onkol. 2022. doi: 10.1007/s00066-022-01942-1.2: Stummer W, Pichlmeier U, Meinel T, Wiestler OD, Zanella F, Reulen HJ; Lancet Oncol. 2006. doi: 10.1016/S1470-2045(06)70665-9.3: Yamamoto J, Ogura S, Shimajiri S, Nakano Y, Akiba D, Kitagawa T, Ueta K, Tanaka T, Nishizawa S. Mol Med Rep. 2015. doi: 10.3892/mmr.2014.2991. 4: Pepper NB, Eich HT, Müther M, Oertel M, Rehn S, Spille DC, Stummer W. Radiat Oncol. 2024. doi: 10.1186/s13014-024- 02408-7. Keywords: glioblastoma, re-irradiation, radiosensitizer Digital Poster 4673 Standard biological equivalent dose hypofractionated radiotherapy for glioblastoma elderly or frail patients Roberta Muni 1 , Ilaria Verzeletti 2 , Angelo Di Naro 1 , Michele Sala 3 , Francesco Romeo Filippone 1 , Micaela Motta 1 , Fabio Piccoli 1 , Suela Vukcaj 1 , Maurizio Giovanni Agostino Portaluri 1 1 Radiation Oncology, ASST Papa Giovanni XXIII, Bergamo, Italy. 2 Student, School of Medicine and Surgery University of Milano Bicocca, Milan, Italy. 3 Radiology, ASST Papa Giovanni XXIII, Bergamo, Italy
Purpose/Objective: Glioblastoma still represents a poor prognosis disease.
Made with FlippingBook - Share PDF online