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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Friday, December 27, 2024
A strategy of active monitoring may be a safe and viable treatment approach for some patients with (HR)-receptor–positive, HER2-negative, low-risk ductal carcinoma in situ (DCIS), according to research presented during the 2024 San Antonio Breast Cancer Symposium (SABCS; Abstract GS2-05). E. Shelley Hwang, MD, MPH, of Duke University School of Medicine, Durham, North Carolina, and colleagues found that 2-year invasive ipsilateral breast cancer recurrence rates were similar among members of this population who underwent active monitoring and those who underwent guideline-concordant treatment.
Nearly 1,000 women with grade 1 or 2, HR-positive, HER2-negative DCIS with no evidence of invasive cancer were enrolled in the multicenter, randomized clinical trial. Approximately half of the participants were randomly assigned to undergo either active monitoring, and the other half, guideline-concordant treatment consisting of surgery with or without adjuvant radiation. Endocrine therapy was offered to both groups, and surgery was recommended to patients who underwent active monitoring if invasive disease progression was observed.
At follow-up of 24 months, the investigators reported that 27 patients who received guideline-concordant treatment and 19 who underwent active monitoring had been diagnosed with invasive ipsilateral breast cancer. The 2-year cumulative rates of invasive ipsilateral breast cancer were 5.9% and 4.2%, respectively, which met the threshold for noninferiority.
Because 46% of patients who received guideline-concordant care declined surgery, the researchers performed a separate analysis of 673 patients who adhered to their assigned treatment. They found that the 2-year rate of invasive ipsilateral breast cancer was 8.7% among patients who received guideline-concordant treatment and 3.1% among those who underwent active monitoring, a difference that was not statistically significant. Finally, 71.3% of patients who underwent active monitoring received endocrine therapy vs 65.5% who received guideline-concordant care, and rates of invasive ipsilateral cancer were 3.21% and 7.15% among these patients, respectively.
Disclosure: Dr. Hwang reported no conflicts of interest. For disclosures of the other study authors, visit sabcs.org.
2024 San Antonio Breast Cancer Symposium
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