2719 - The PREDICT II Registry: A Prospective Study to Evaluate the Clinical Utility of a 7-Gene Predictive Biosignature on Treatment Decisions in Patients with Ductal Carcinoma In Situ

R. A. Rabinovitch¹, P. W. Whitworth², P. I. Borgen³, K. Mittal⁴, S. Shivers⁴, and T. Bremer⁴; ¹University of Colorado Cancer Center, Aurora, CO, ²University of Tennessee, Knoxville, TN, ³Maimonides Medical Center, Brooklyn, NY, ⁴PreludeDx, Laguna Hills, CA

Purpose/Objective(s): For women with ductal carcinoma in situ (DCIS) treated with breast conserving surgery (BCS), the bene?t of adjuvant radiation therapy (RT) remains controversial. Evidence from randomized clinical trials supports the role of RT in reducing the risk of local recurrence, current guidelines generally recommend RT for all women having BCS even though 70-80% do not recur after BCS alone. In response to the need for prognostic and predictive tools for DCIS, a 7-gene predictive biosignature was developed to better assess risk and RT benefit. The test provides a validated Decision Score (DS) for assessing 10-year risk of recurrence and RT bene?t using individual tumor biology, as assessed by clinical and pathologic biomarkers. The primary objective of the PREDICT registries is to understand the decision impact such a tool has on treatment decisions. Materials/

Methods: This is a multicenter, prospective, observational registry for women diagnosed with DCIS. The primary endpoints are changes in treatment recommendations for surgical, radiation, and hormonal therapy. Secondary endpoints are identi?cation of key drivers for treatment recommendations, such as age, size, grade, patient preference and biosignature status. The study includes females age 26-85 who are candidates for BCS and eligible for RT and/or systemic treatment. Subjects must not have been previously treated for DCIS or have previous or current invasive or microinvasive breast cancer. After DCIS diagnosis, sites will send the most representative tissue block or sections to a CLIA lab for biosignature testing. Treating physicians will complete a treatment recommendation survey before and after receiving the biosignature test results. Test results, treatment recommendations, patient preferences and clinicopathologic features will be stored in a de-identi?ed registry. Women will be followed for up to 10 years. Changes in pre- and post-test treatment recommendations will be analyzed using McNemars test (alpha level = 0.05). Multivariate logistic regression will be used to determine odds ratios of clinicopathologic factors leading to pre- and post-test treatment recommendations. Pre-test covariates include patient age, tumor size, palpability, margin status, hormone receptor status, nuclear grade, tumor necrosis, family history of breast cancer, race, ethnicity and patient preference, as well as physician specialty (surgeons vs. radiation oncologists) and post-test covariates will also include the biosignature score. Differences in recurrence-free and overall survival will be assessed by Kaplan-Meier survival analysis using the log-rank test and/or the Cox Proportional Hazards model. The study will enroll up to 3,000 women from about 30 sites across the US. The study has been approved by WCG IRB (Tracking #20172841) and/or local IRBs at each site. ClinicalTrials.gov: NCT03448926.
Results: TBD
Conclusion: TBD