Radiotherapy may be omitted in breast cancer patients 

The prospective cohort study LUMINA found that women ≥55 years with T1N0, G1–2 luminal A breast cancer, who underwent breast-conserving surgery (BCS), had a very low rate of local recurrence if they were treated exclusively with endocrine therapy and not with radiotherapy. These results indicate that the morbidity and costs of radiotherapy could be avoided in a substantial proportion of women with breast cancer. 

“Although the risk of local recurrence after BCS is reduced by approximately 67% with adjuvant radiotherapy, this treatment may be omitted in very-low-risk patients,” reasoned Prof. Timothy Whelan (McMaster University, Canada). The LUMINA study (NCT01791829) aimed to determine whether identifying luminal A subtype breast cancer in combination with known clinical pathological factors could identify very-low-risk patients in whom radiotherapy could be omitted after BCS [1]. For this purpose, a prospective analysis was conducted including 500 women ≥55 years with T1N0, G1-2 luminal A-type ductal breast cancer who only followed endocrine therapy, and not radiotherapy, after BCS. Additionally, only patients who had ≤13.25% on a Ki67-test were included in the analysis. The primary endpoint was met if the local recurrence rate was <5% after 5 years.

After 5 years of follow-up, the local recurrence rate was 2.3% (90% CI 1.3–3.8). Moreover, the rates of contralateral breast cancer (1.9%) and any recurrence (2.7%) were low. The disease-free survival after 5 years was 89.9%, with 47 reported events, of which 23 were second primary non-breast cancers. The overall survival after 5 years was 97.2%, but only 1 out of 13 deaths was breast cancer-related.

“This study showed that the risk for local recurrence after BCS is very low in a substantial proportion of patients with breast cancer,” stated Prof. Whelan. “We estimate that radiotherapy could be omitted in approximately 30,000 to 40,000 of the 300,000 patients who are newly diagnosed with invasive breast cancer in North America each year, avoiding the morbidity, inconvenience, and costs of this therapy.”

1. Whelan T, et al. LUMINA: A prospective trial omitting radiotherapy (RT) following breast conserving surgery (BCS) in T1N0 luminal A breast cancer (BC). LBA501, ASCO 2022 Annual Meeting, 3‒7 June, Chicago, IL, USA.

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Posted on 5 August, 2022