Outcome of different radiotherapy strategies after breast conserving surgery in patients with ductal carcinoma in situ (DCIS)

Fredrik Wärnberg; Charlotta Wadsten; Andreas Karakatsanis; Roger Olofsson Bagge; Erik Holmberg; Henrik Lindman; Elinor Sawyer; Frank Vicini; G Bruce Mann; Per Karlsson

doi:10.1080/0284186X.2023.2245552

Outcome of different radiotherapy strategies after breast conserving surgery in patients with ductal carcinoma in situ (DCIS)

Acta Oncol. 2023 Sep;62(9):1045-1051. doi: 10.1080/0284186X.2023.2245552. Epub 2023 Aug 12.

Authors

Fredrik Wärnberg^{1

2}, Charlotta Wadsten³, Andreas Karakatsanis⁴, Roger Olofsson Bagge^{1

2}, Erik Holmberg⁵, Henrik Lindman⁶, Elinor Sawyer⁷, Frank Vicini⁸, G Bruce Mann⁹, Per Karlsson⁵

Affiliations

¹ Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
² Department of Surgery, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden.
³ Department of Surgery, Sundsvall Hospital, Umeå University, Umeå, Sweden.
⁴ Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
⁵ Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
⁶ Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
⁷ Guys Cancer centre, Kings College London, London, UK.
⁸ Regional Oncologic Centre, NRG, Oncology, and 21st Century Oncology, Pontiac, MI, USA.
⁹ Department of Surgery, The University of Melbourne, Melbourne, Australia.

PMID: 37571927
DOI: 10.1080/0284186X.2023.2245552

Abstract

Background: Adjuvant radiotherapy (RT) after breast-conserving surgery for DCIS lowers the relative local recurrence risk by half. To identify a low-risk group with the minimal benefit of RT could avoid side effects and spare costs. In this study, the outcome was compared for different RT-strategies using data from the randomized SweDCIS trial.

Material and methods: Five strategies were compared in a Swedish setting: RT-to-none or all, RT to high-risk women defined by DCISionRT, modified Radiation Therapy Oncology Group (RTOG) 9804 criteria, and Swedish Guidelines. Ten-year recurrence risks and cost including adjuvant RT and local recurrence treatment cost were calculated.

Results: The mean age at recurrence was 64.4 years (36-90) and the mean cost for treating a recurrence was $21,104. In the SweDCIS cohort (n = 504), 59 women developed DCIS, and 31 invasive recurrence. Ten-year absolute local recurrence risk (invasive and DCIS) according to different strategies varied between 18.6% (12.5-23.6%) and 7.8% (5.0-12.6%) for RT-to-none or to-all, with an additional cost of $2614 US dollars per women and $24,201 per prevented recurrence for RT-to-all. The risk differences between other strategies were not statistically significant, but the larger proportion receiving RT, the fewer recurrences. DCISionRT spared 48% from RT with 8.1% less recurrences compared to RT-to-none, and a cost of $10,534 per prevented recurrence with additional cost depending on the price of the test. RTOG 9804 spared 39% from RT, with 9.7% less recurrences, $9525 per prevented recurrence and Swedish Guidelines spared 13% from RT, with 10.0% less recurrences, and $21,521 per prevented recurrence.

Conclusion: It seems reasonable to omit RT in pre-specified low-risk groups with minimal effect on recurrence risk. Costs per prevented recurrence varied more than two-fold but which strategy that could be considered most cost-effective needs to be further evaluated, including the DCISionRT-test price.

Keywords: DCIS; cost; outcome; radiotherapy; recurrence.

MeSH terms

Breast Neoplasms* / surgery
Carcinoma in Situ* / pathology
Carcinoma, Ductal, Breast* / pathology
Carcinoma, Intraductal, Noninfiltrating* / surgery
Female
Humans
Mastectomy, Segmental
Neoplasm Recurrence, Local / surgery
Radiation Oncology*
Radiotherapy, Adjuvant