ESTRO 2022

Session Item

Monday

May 09

11:40 - 12:40

Room D1

Highlights of Proffered Papers - Latest Clinical Trials

Chair: , United Kingdom;

Chair: , The Netherlands

Session Code: 3290

Session Type: Proffered Papers

Track: Interdisciplinary

11:40 - 11:50

Acute toxicity after loco regional breast radiation therapy in the randomized DBCG SKAGEN trial 1

Marie Louise Milo, Denmark

Presentation Number: OC-0829

Abstract

Abstract Title:

Acute toxicity after loco regional breast radiation therapy in the randomized DBCG SKAGEN trial 1

Authors:

Marie Louise Milo¹, Tamás Lörincz¹, Mette Holck Nielsen², Claus Kamby³, Troels Bechmann⁴, Sami Al-Rawi⁵, Louise Wichmann Matthiessen⁶, Mechthild Krause⁷, Andreas Schreiber⁸, Ingvil Mjaaland⁹, Unn-Mariam Kasti¹⁰, Eigil Støre Brix¹¹, piotr kedzierawski¹², Tanja Marinko¹³, Carine kirkove¹⁴, Jens Overgaard¹⁵, Birgitte Vrou Offersen¹⁵

¹Aalborg University Hospital, Department of Oncology, Aalborg, Denmark; ²Odense University Hospital, Department of Oncology, Odense, Denmark; ³Rigshospitalet, Department of Oncology, Copenhagen, Denmark; ⁴Vejle Hospital, Department of Oncology, Vejle, Denmark; ⁵Naestved Hospital, Department of Oncology, Naestved, Denmark; ⁶Herlev Universiyt Hospital, Department of Oncology, Herlev, Denmark; ⁷University Hospital and Faculty of Medicine Carl Gustav Carus, Department of Radiation Oncology and OncoRay, Heidelberg, Germany; ⁸Dresen Hospital, Department of Radiotherapy, Dresen, Germany; ⁹Stavanger University Hospital, Department of Oncology, Stavanger, Norway; ¹⁰Sørlandet Hospital, Department of Oncology, Kristiansand, Norway; ¹¹University of North Norway, Department of Oncology, Tromsø, Norway; ¹²Holycross Cancer Center, Department of Radiotherapy, Kielce, Poland; ¹³Institute of Oncology Ljubljana, Department of Radiotherapy, Ljubljana, Slovenia; ¹⁴Cliniques Universitaires St-Luc, Department of Oncology, Brussel, Belgium; ¹⁵Aarhus University Hospital, Department of Experimental Clinical Oncology, Aarhus, Denmark

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Purpose or Objective

Background: In the past, poor outcome after hypofractionated radiation therapy (RT) in breast cancer patients (pts) was observed. Thus, in Denmark, normofractionation with 50Gy/25fr was standard for early breast cancer (BC) RT since 1982. In 2014, moderately hypofractionated RT became standard for pts treated with whole breast RT based on early results from the Danish Breast Cancer Group (DBCG) Hypo trial. The DBCG Skagen trial 1 was then initiated to evaluate the risks and gains following 50Gy/25fr versus moderately hypofractionated 40Gy/15fr loco-regional RT of BC pts with indication for loco-regional RT (LR-RT). The primary endpoint was 3-year arm lymph edema. In this study, we report evaluation of acute toxicity, a secondary outcome of the trial.

Material and Methods

Method: In this international, multi-center, randomized trial, pts operated for early BC, pT1-3, pN0-N3, M0 with an indication for LR-RT were randomly assigned 50Gy/25fr (standard) versus 40Gy/15fr (experimental). Acute toxicities were graded using the CTCAE 4.0 and the RTOG/EORTC criteria at baseline, three and five weeks after start of RT. Hereafter, evaluations were made every 2 weeks as long as there were acute morbidities above baseline level. The maximum grading is reported here. Each center was requested to report acute morbidities in 40 consecutive pts.

Results

Results: From 2015 to 2021, 511 pts from six countries were evaluated for acute toxicity. In total, 259 pts were randomized to 50Gy/25fr and 252 pts to 40Gy/15fr No acute grade 4-5 toxicities were observed. For both randomization arms, grade 3 toxicity was observed in only 10% of the pts. The most common grade 2 toxicities were dermatitis 52% (50Gy/25fr) versus 27% (40Gy15fr) and fatigue 18% (50Gy/25fr) versus 19% (40Gy15fr), respectively. The most common grade 1 toxicities were dermatitis, pruritus and fatigue.

Conclusion

Conclusion: In general, the frequency and severity of acute toxicities were low for pts treated with LR-RT regardless the randomization arm. Thus, moderately hypofractionated RT did not raise any safety concerns. A more detailed analysis of the acute morbidities will be provided at the ESTRO conference. Radiation-associated late morbidities are currently investigated as part of 10-year follow-up.