Comment: Biomarker guidance allows patients 55 or older with low-grade luminal A-type breast cancer to avoid radiation therapy

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Published: 7 Jun 2022
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Dr Bishal Gyawali - Queen's University, Kingston, Canada

Dr Bishal Gyawali comments on the LUMINA trial from ASCO 2022, initially explainsing the trial design and the aims and objectives of the trial.

Luminal A is the most common subtype of breast cancer and ii represents 50-60% of all breast cancers diagnosed annually.

The single-arm prospective phase III LUMINA trial enrolled 500 patients from 26 centres in Canada who had a Ki67 tumour cell count of 13.25% or less. 

The  LUMINA results showed that women with low levels of the Ki67 biomarker can avoid outcomes  related to radiotherapy, including significant acute and late side effects; such effects include fatigue and rare life-threatening side effects of cardiac disease and second cancers

Dr Gyawali explains the results of this study and how it can impact the future treatment of cancer patients.

Watch Dr Whelan's press conference on the study here

Watch Dr Speers comment on the study here

Watch our interview with Dr Whelan here

Read our news story about the study here

I wanted to give a shout-out to the LUMINA trial because it’s done by the Canadian group and I am in Canada now. This is a very pragmatic trial, I’m not biased, this is a very good trial. 

This is a trial that looked at T1 N0 luminal A breast cancer, grade 1-2, and the question they were asking is should we give them radiotherapy or rather, I would say, can we spare them radiotherapy? Is it safe enough not to give them radiotherapy? They tried to answer this very pragmatically. They defined a non-inferiority limit of less than 5%. So if the five year local regional recurrence rate, the 95% confidence interval’s upper bound was less than 5% then they would consider it non-inferior, that means they would be happy with skipping radiotherapy. 

What they found was it was five year local regional recurrence rate was 2.3% and the 95% confidence interval went from 1.3% to 3.8%, so that 3.8% is less than 5% so we can consider it non-inferior. 

So this is practice-changing data. When the patient comes back to my clinic next week and she is a T1 N0 luminal A breast cancer patient and asks me, ‘Do I need radiotherapy after surgery?’ I can say that the five year local regional recurrence rate is around 2.3%. This new data that was showed at ASCO proved that it is less than 5% which we had considered to be non-inferior and I would be happy skipping it. But if she says, ‘No, that’s too high a percent for me, I don’t want to take chances,’ I would recommend her radiotherapy. But obviously I would refer her to a radiation oncologist but this data looked very interesting to me, even as a medical oncologist.