- Compared with anti-hormone treatment (AHT) alone, adding whole breast irradiation (WBI) significantly improves local recurrence and disease-free survival in postmenopausal, low-risk, hormone-driven breast cancer patients in the long-term (10 years).
- The omission of radiotherapy (RT) is an independent risk factor for local recurrence in this population.
Why this matters
- Improving control of the tumour at the primary site may translate into better survival in future years.
- 869 postmenopausal women with early, low-risk breast cancer were enrolled in the Austrian Breast and Colorectal Cancer Study Group (ABCSG) 8A trial and randomised to receive AHT +/- RT after breast-conserving surgery.
- Clinical endpoint included overall survival (OS) and survival free from local recurrence (LRFS), regional recurrence (RRFS), distant metastases (DMFS), disease (DFS), and recurrence (RFS).
- Funding: Astra Zeneca.
- 10-year LRFS was significantly higher in women receiving WBI (RT group) as compared to women who did not (no-RT group) (97.5% vs 92.5%; log-rank P=0.0004).
- DFS rate was significantly higher in RT group than in no RT group (94.5% vs 88.4%; HR: 0.56; log-rank P=0.0156).
- Irradiation led to a 75% reduction of the risk of recurrence in the subgroup of women who had only the sentinel lymph nodes removed (HR: 0.25; log-rank P=0.0074).
- Patients at high risk (based on Ki-67 and HER2 status) did not show a higher risk of local recurrence, but more data are required.
- No significant differences were observed in RRFS, DMFS, and OS.
“These new results can help women and doctors choose the best treatment for breast cancer. Let’s keep in mind that now there are also other ways of delivering radiotherapy to the breast that are less toxic and time‐consuming compared to WBI.” Umberto Ricardi, ESTRO President, Head of the Department of Oncology, University of Turin, Italy.