Comparison of operative to monitoring and endocrine therapy for low-risk DCIS (COMET study).

Abstract

TPS599Background: Approximately 50,000 women in the U.S. are diagnosed with ductal carcinoma in situ (DCIS) each year. Without treatment, it is estimated that only 20-30% of DCIS will lead to invasive breast cancer. However, over 97% of women are currently treated with guideline-concordant care (GCC) including surgery and/or radiation. An alternative to GCC is active surveillance (AS) which focuses on early detection of invasion rather than “treatment” of DCIS. The COMET study will compare risks and benefits of AS versus GCC in the setting of a Phase III pragmatic prospective randomized clinical trial. The study is funded by the Patient-Centered Outcomes Research Institute (PCORI). Methods: The primary objective is to assess whether the 2-, 5-, and 7-year ipsilateral invasive breast cancer rate for AS is non-inferior to that for GCC. Secondary objectives include determining whether AS is non-inferior to GCC for 2-year mastectomy rate; breast conservation rate; contralateral breast cancer rate; overall and...