Two-year cumulative rate of invasive ipsilateral breast cancer 5.9 and 4.2 percent for guideline-concordant care, active monitoring
By Elana Gotkine HealthDay Reporter
FRIDAY, Dec. 13, 2024 (HealthDay News) — For patients with ductal carcinoma in situ (DCIS), active monitoring (AM) is noninferior to guideline-concordant care (GCC) that involves surgery with or without adjuvant radiation, according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 10 to 13 in San Antonio.
E. Shelley Hwang, M.D., M.P.H., from the Duke University School of Medicine in Durham, North Carolina, and colleagues examined the outcomes of 995 participants with grade 1 or 2 hormone receptor-positive, human epidermal growth factor receptor 2-negative DCIS enrolled in the Comparing an Operation to Monitoring, with or without Endocrine Therapy for low risk DCIS trial who were randomly assigned to GCC (473 patients) or AM (484 patients). Participants in the AM group underwent surgical intervention only upon invasive progression diagnosis, or they could elect to have surgery at any time. Patients were allowed to receive endocrine therapy if desired, in both treatment arms.
The researchers found that 27 patients in the GCC arm and 19 in the AM arm had been diagnosed with invasive ipsilateral breast cancer after 24 months of follow-up. The two-year cumulative rate of invasive ipsilateral breast cancer was 5.9 and 4.2 percent for the GCC and AM arms, respectively, meeting the threshold for noninferiority. More patients in the AM versus GCC arm received endocrine therapy (71.3 versus 65.5 percent). Of those receiving endocrine therapy, invasive ipsilateral cancer was seen in 7.15 percent of patients in the GCC arm and 3.21 percent in the AM arm.
“Omission of surgery has been highly controversial, with both patients and providers fearing that it might result in an unacceptably high rate of patients who develop invasive cancer,” Hwang said in a statement. “Our findings are reassuring, and longer-term follow up will have important implications for the future inclusion of active monitoring as a treatment option for low-risk DCIS.”
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