Annually, approximately 65 million women undergo mammographic screening in the United States at a cost of over $13 billion. Although mammography has achieved a reduction in breast cancer mortality rates, there is increasing recognition that this benefit has been accompanied by “overdiagnosis.” Overdiagnosis occurs when cancer screening detects conditions that may never cause illness if left untreated; in these cases, treatment provides no benefit and can only harm. For breast cancer, much of the burden of overdiagnosis derives from the detection of DCIS, a diagnosis faced by over 60,000 women in the United States annually. DCIS is a pre-invasive condition, which lacks the potential to spread and cause illness unless it undergoes progression to invasive cancer. When diagnosed, DCIS is conventionally treated with surgery, often in combination with radiation. These treatments are the same as those offered to women with invasive cancer; side effects of these therapies can include long-term pain, worry, altered body image, or rarely, secondary cancers. Since without treatment, only 20-30 percent of DCIS cases will likely progress to invasive cancer, there is an opportunity to manage some patients with low-risk DCIS with surveillance rather than surgery, thereby reducing overtreatment. The proposal directly addresses one of the PCORI priority topics as well as one of the top 25 Institute of Medicine (IOM) Initial Priority Topics for Comparative Effectiveness Research.
Study Aims: The primary objective of the study is to assess whether the invasive cancer rate in the affected breast is the same for women undergoing standard care compared to surveillance. Secondary objectives will be to compare mastectomy rate, survival endpoints, and quality-of-life endpoints between standard care and surveillance groups.
Study Description/Overall Study Design: We have designed a large pragmatic randomized trial comparing operative to medical endocrine therapy for low-risk DCIS (COMET trial). We will compare patients with low-risk DCIS who are randomized to receive either standard care or surveillance. Patients randomized to the standard care group will choose between currently recommended treatment options including surgery and radiation; those in the surveillance group will be monitored closely, with surgery or radiation only upon progression of disease. Patients in both the GCC and AS groups will be free to decide whether to choose endocrine therapy. Study participants will be recruited at 100 participating study sites during the 48-month recruitment period. We will recruit 446 patients to each study arm. The goal of the proposed study is to gather evidence to help future patients consider the range of treatment choices for DCIS, including standard therapies as well as surveillance. We seek to determine whether there are some groups of patients with DCIS who do not benefit from standard treatment and who could thus be managed with surveillance.