Ductal carcinoma in situ (DCIS) tumours are precancerous but do have the potential to become invasive breast cancer. DCIS can range from low risk, unlikely to become invasive cancer in short-term or ever, to high risk, prone to progressing to invasion early. Breast conserving surgery (removing tumour, not entire breast) is a common treatment. Radiotherapy after breast conserving surgery (BCS) for DCIS has been shown to reduce the risk of cancer coming back by half. International guidelines recommend radiotherapy for DCIS after BCS, except in low-risk cases.
This study looked at how radiotherapy is currently recommended for DCIS tumours in Australia using BreastSurgANZ Quality Audit (BQA) data for 2018 to 2022.
The study found:
- Patients were more likely to be treated with BCS (over two thirds of patients), rather than mastectomy
- 25% of BCS patients did not have radiotherapy after BCS
- Radiotherapy was not consistently excluded from treatment across Australia for ‘low risk’ DCIS cases when using traditional methods of defining low risk (e.g. using mix of patient age, tumour size, tumour grade, whether tumour found through breast screening).
This study concludes that clear methods should be developed for when radiotherapy should be given or not given for DCIS tumours, to improve consistency of radiotherapy recommendation by surgeons. Molecular profiling tools for assessing risk in DCIS cases (i.e. more recently developed tests looking at genes in the cancer cells, such as Oncotype DX or DCISionRT) could be used to guide these recommendations.
Reference:
Ofri, A., Melanie Tam, S. K., Gill, S., & Spillane, A. J. (2025). Current pattern of care in radiation therapy for DCIS in Australia and New Zealand - where are we heading?. Breast (Edinburgh, Scotland), 82, 104482. https://doi.org/10.1016/j.breast.2025.104482