Table of Contents
Posted on August 15, 2025
INTRO:
Do you have breast cancer? Want to know earlier if it is recurring? There was a new study which I think is the future of cancer surveillance. It looks at bloodwork to detect shedded pieces or DNA of cancer in the bloodstream. This is often detectable before there is enough cancer to be seen on a scan. The premise of this is what teams like Galleri do when they are screening blood for cancers.
STUDY:
This is a recent study out of the New England Journal of Medicine, published June 2025. “First Line Camizestrant for Emerging ESR1-Mutated Advanced Breast Cancer.” This was looking at breast cancer patients who become resistant to the most common treatment for breast cancer with an aromatase inhibitor for those who are estrogen receptor positive with advanced breast cancer.
The study was done by a pharma company, so read it with a tiny grain of salt.
- 3256 Patients had ER positive HER2 negative tumors
- They were looking of ESR1 mutations in circulating tumor DNA. This was found in 315 patients. Half of these were then changed to the new medication, half remained on the aromatase inhibitor.
- Testing was done every 2-3 months
- If there was an ESR1 mutation but no findings on radiology exams, they were changed to the new medication camizestrant instead of aromatase inhibitor. Placebos were used so patients would not now if they were on aromatase or the new medication.
- Primary outcome was investigator assessed progression free survival.
FINDINGS
- Median progression free survival was 16 months in the camizestrant group and 9 months in the aromatase inhibitor group.
- Median time until patient reported decline in health and quality of life was at 23 months with camizestrant and 6 months with aromatase inhibitor.
- They conclude camizestrant with continuation of the CDK4/6 inhibitor had significantly longer progression free survival than those on the aromatase inhibitor combo.
MY THOUGHTS?
I always a little wary of studies done by the pharma company, but they had a blinded placebo trial with good numbers, so I think there is likely a real improvement here. What I found more interesting is the focus on testing the blood for the DNA mutation. Being able to find recurrences before they are large enough to be seen on radiology tests is exciting. Targeting those mutations with new medications is exciting. Understanding why chemotherapeutic agents stop working (here due to a new mutation in the ESR1) and how to monitor that and treat it is exciting. Go science.
MEDICAL CITATION
Study in New England Journal link.
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