ESTRO 2023 - Abstract Book

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ESTRO 2023

We conducted a retrospective study of 156 patients diagnosed with DCIS from January 2009 to December 2018. Among them, 83 patients were treated with mastectomy and 73 with BCS followed by RT. Clinical characteristics: Mean age 54 years (30-85), tumor grade: 1 (27 patients), 2 (48 patients), 3 (81 patients), radiotherapy treatment: 50 Gy, 2Gy/fx (49 patients) or 42.56 Gy, 2.66Gy/fx (24 patients); +/-10-16 Gy boost (40 patients). Overall survival (OS), disease-free survival (DFS) and local recurrence-free survival (LRFS) rates were compared between the two treatment modalities. The study sample was sent a survey between June 2021 and October 2021. Sixty-five out of 156 patients (35 from the mastectomy group and 30 from the BCS+RT group) agreed to answer the quality of life questionnaires (EORTC_QLQ_C30 and BR-23 module). Results After a follow-up of 49 months (20 – 123 months), among the 65 respondents, median age was 52 years (31-75 years) and median time from diagnosis to survey was 62 months (35-132 months). Overall survival rates at 5 and 10 years was 100% in both groups. There were no significant differences between groups for disease-free survival or local-relapse-free survival (Figure 1). There were no significant difference between treatments in any item of the EORTC_QLQ_C30 or BR-23 module questionnaires. Median global health status/QoL was 83.33 in both groups. There was non-significant trends on item 21 (did you feel nervous?) of EORTC_QLQ_C30 in favor of conservative treatment (p=0.056). Statistics: Kaplan-Meier, log-rank, Student’s-T-test.

Conclusion The findings support equivalence of BCS followed by RT and mastectomy plus reconstruction with regard to clinical outcome and QoL. These findings may help in making decisions about preference for women with DCIS.

PO-1253 Single fraction ablative preoperative RT for early-stage BC, the CRYSTAL trial: preliminary results

M.A. Zerella 1 , M. Zaffaroni 1 , G. Ronci 2 , S. Dicuonzo 1 , D.P. Rojas 1 , A. Morra 1 , M.A. Gerardi 1 , C. Fodor 1 , E. Rondi 2,1 , S. Vigorito 1 , S. Penco 3 , M. Sargenti 4 , P. Baratella 4 , E. Vicini 4 , C. Morigi 4 , S. Kahler-Ribeiro-Fontana 4 , V.E. Galimberti 4 , S. Gandini 5 , E. De Camilli 6 , G. Renne 6 , F. Cattani 2 , P. Veronesi 4,8 , R. Orecchia 7 , B.A. Jereczek-Fossa 1,9 , M.C. Leonardi 1 1 Istituto Europeo di Oncologia, Radiotherapy, Milan, Italy; 2 Istituto Europeo di Oncologia, Medical Physics, Milan, Italy; 3 Istituto Europeo di Oncologia, Breast Radiology, Milan, Italy; 4 Istituto Europeo di Oncologia, Breast Surgery, Milan, Italy; 5 Istituto Europeo di Oncologia, Experimental Oncology, Milan, Italy; 6 Istituto Europeo di Oncologia, Pathology, Milan, Italy; 7 Istituto Europeo di Oncologia, Scientific Directorate, Milan, Italy; 8 Università degli Studi di Milano, Department of Oncology and Hemato-oncology, Milano, Italy; 9 Università degli Studi di Milano, Department of Oncology and Hemato oncology, Milan, Italy Purpose or Objective Based on the observation that most local recurrences in breast cancer (BC) undergoing breast-conserving surgery (BCS) occur near the tumor bed, accelerated partial breast irradiation (APBI) has been gaining ground as an attractive alternative in selected patient, with a growing interest in shifting radiotherapy (RT) from postoperative to preoperative setting.The aim of this study is to report preliminary results of the Phase I CRYSTAL trial, in which preoperative RT is delivered in a single fraction using CyberKnife for selected BC patients. Materials and Methods CRYSTAL is a monocentric phase I/II, single-arm and open-label study planning to enroll 79 patients over 5 years.Patients receive an ablative dose to the tumor before surgery using CyberKnife. The primary endpoint for the phase I study is the identification of the maximum tolerated dose (MTD) which meets a specific target toxicity level (no RTOG grade 3-4 toxicity).Dose escalation was designed as a 3+3 rule-based study, proceeding with cohorts of 3 patients testing 3 dose levels: 18Gy,21Gy,24Gy. The minimum of the phase I population would be 9, if there was no Grade 3-4 toxicity, to a maximum of 18 if in case of toxicity in each dose escalation step. For the phase II study the aim is the evaluation of treatment efficacy measured in terms of pathological complete response rate. The project was registered at