ESTRO 2022 - Abstract Book

S1189

Abstract book

ESTRO 2022

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Conclusion SBRT for prostate cancer is a safe and effective treatment. CT-guided SBRT involves acceptable toxicity , however it needs additional equipment (ie. fiducials placement, ExacTrac® system ) to assure interfraction organ-motion control and delivery precision. SMART for prostate cancer confirms efficacy and can reduce toxicity: on-line adaptive and real-tracking improve precision and safety , with a slight difference in the time of daily treatment. Further studies to evaluate the optimal balance between clinical advantages of SMART technologies and additional cost in terms of time and complexity are needed.

PO-1402 Hypofractionation in localised prostate cancer

V. Navarro Aznar 1 , A. Méndez Villamón 1 , C. García Aguilera 1 , J.M. Ponce Ortega 1 , M. Cerrolaza Pascual 1 , A. Lanuza Carnicer 2 , J. Díaz Abad 1 , C. Escuín Troncho 1 , B. García Gimeno 1 , D. Villa Gazulla 1 1 Hospital Universitario Miguel Servet, Radiation Oncology, Zaragoza, Spain; 2 Hospital Universitario Miguel Servet, Radiation oncology, Zaragoza, Spain Purpose or Objective To analyse overall survival (OS); cancer-specific survival (CSS); disease-free survival (DFS) and acute and chronic toxicity in patients with localised prostate cancer treated with extracranial stereotactic radiotherapy (SBRT). Materials and Methods We retrospectively analysed 366 patients with localised prostate cancer treated with SBRT between February 2014 and October 2021. All received dietary recommendations and rectal preparation with enema the night before the planning CT scan, which was performed with diuresis control, immobilisation system with wedge under knees and abdominal compressor with 3mm cuts. Intensity modulated radiotherapy was applied using a Linear Electron Accelerator with a photon beam energy of 6MV, administering 35Gy in 7 sessions over the prostate volume with a margin of 3mm. Weekly follow-up was carried out during the treatment and once it was finished: at one month, 3 months, to continue with six-month follow-up. Results The median age was 72 years. 64.66% had received previous hormone treatment. 38% were low risk, 56% intermediate risk and 6% high risk.

With a median follow-up of 39 months, DFS was 97.81% and CSS was 99.45% with an OS of 90.22%. The IPSS score increased a median of 2 points and normalised after 6 months to baseline values.

52% experienced acute genitourinary toxicity G1, 4% G2, and 1% G3. Acute G1 gastrointestinal toxicity was experienced in 9% and G2 in 1%. After 6 months, G1 genitourinary toxicity was reported in 3%, G2 in 1%, G1 gastrointestinal toxicity in 1% and G2 in 1%. No toxicities ≥ grade 3 were observed.

Conclusion SBRT 35Gy is positioned as a safe treatment, with excellent disease control, requiring longer-term follow-up.

PO-1403 Postoperative radiatiotherapy in prostate cancer: long-terms results of a single institution

A. Hervás 1 , J.A. Domínguez 2 , V. Duque 2 , F. López 2 , M. Valero 2 , M.C. Vallejo 2 , D. Sevillano 3 , J.D. García 3 , S. Sancho 2

1 H, Universitario Ramón y Cajal, Radiation Oncology, Madrid, Spain; 2 H. Universitario Ramón y Cajal, Radiation Oncology, Madrid, Spain; 3 H. Universitario Ramón y Cajal, Radiophisics, Madrid, Spain