ONCOTYPE IQ for DCIS: A 12-year update on the ECOG-ACRIN E5194 study

One discussion last week included Dr. Wood’s ONCOTYPE IQ for DICS, Trial E5194.

Reference: Solin LJ, et al. Surgical excision without radiation for ductal carcinoma in situ of the breast: 12-year results from the ECOG-ACRIN E5194 study. Journal of Clinical Oncology. 2015 Nov 20;33(33):3938-3944. doi: 10.1200/JCO.2015.60.8588

ClinicalTrials.gov NCT00002934.

Summary: The Eastern Cooperative Oncology Group–American College of Radiology Imaging Network (ECOG-ACRIN; formerly the Eastern Cooperative Oncology Group) Cancer Research Group E5194 study (a nonrandomized clinical trial) prospectively enrolled patients for whom surgical excision alone (without radiation) was thought to be a reasonable treatment option on the basis of low-risk clinical and pathologic characteristics. This report provides updated results from the ECOG-ACRIN E5194 study, including 10- and 12-year outcomes.

Patients were enrolled onto one of two study cohorts: cohort 1: low- or intermediate-grade DCIS, tumor size 2.5 cm or smaller (n = 561); or cohort 2: high-grade DCIS, tumor size 1 cm or smaller (n = 104). Protocol specifications included excision of the DCIS tumor with a minimum negative margin width of at least 3 mm. Tamoxifen (not randomly assigned) was given to 30% of the patients. An IBE was defined as local recurrence of DCIS or invasive carcinoma in the treated breast.

RESULTS: There were 99 IBEs, of which 51 (52%) were invasive. The IBE and invasive IBE rates increased over time in both cohorts. The 12-year rates of developing an IBE were 14.4% for cohort 1 and 24.6% for cohort 2 (P = .003). The 12-year rates of developing an invasive IBE were 7.5% and 13.4%, respectively (P = .08). On multivariable analysis, study cohort and tumor size were both significantly associated with developing an IBE (P = .009 and P = .03, respectively).

CONCLUSION: For patients with DCIS selected for favorable clinical and pathologic characteristics and treated with excision without radiation, the risks of developing an IBE and an invasive IBE increased through 12 years of follow-up, without plateau. These data help inform the treatment decision-making process for patients and their physicians.

Additional Reading: Rakovitch E, et al. Refined estimates of local recurrence risk by DCIS score adjusting for clinicopathological features: a combined analysis of ECOG-ACRIN E5194 and Ontario DCIS cohort studies. Breast Cancer Research and Treatment. 2018 Jun;169(2):359-369. doi: 10.1007/s10549-018-4693-2.

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