PROJECT SUMMARY/ABSTRACT: CairnSurgical, Inc., a Dartmouth spin-off company, will conduct a prospective, multicenter, 1:1 randomized, controlled trial designed to evaluate the safety and effectiveness of its Breast Cancer Locator (BCL) device in subjects with non-palpable invasive breast cancer or ductal carcinoma in situ (DCIS) under an investigational device exemption (IDE) recently approved by the FDA (Nov 2019). Subjects will be randomized to breast conserving surgery (BCS) utilizing either BCL or wire localization (WL) to guide surgery. BCL is a novel patient- specific, guidance device designed for use in breast conserving surgery (BCS) to (i) eliminate wire localization ? a moderately effective, somewhat costly and certainly inconvenient procedure for patients and surgeons ? and concomitantly to (ii) reduce positive margin rates (PMRs) and subsequent re-excision surgeries ? a significant but unnecessary burden not only on patients but also on the cost of healthcare. In the proposed Direct to Phase II application, Cairn will (i) support 7 clinical sites as part of a multi-center pivotal randomized controlled trial, RCT, (in up to 15 centers; remaining support will derive from recently secured private investment) in 438 subjects (219 per arm) to generate evidence that PMR following BCS using the BCL is reduced relative to standard of care (WL), (ii) evaluate BCL cost-effectiveness through a healthcare economics study to generate data on use, out-comes, and savings to hospitals and payors that support market adoption, and (iii) file a de novo classification request to FDA for BCL PMR reduction marketing claims relative to WL. Based on preliminary results from a recently completed Dartmouth randomized prospective trial23 and several published RCTs of wire localization (see Table 1 in Research Strategy), we have estimated PMR in the WL arm to be 19%. The proposed study design allows definitive evaluation of superiority of BCL, with power sufficient to detect a clinically meaningful, 40% reduction in PMR, from 19% to 11.2%. In preparation for the proposed RCT, CairnSurgical has obtained IDE approval from FDA after successfully completing necessary product development and testing under design controls including, sterilization validation and biocompatibility testing. In addition, we have developed manufacturing processes to fabricate BCL devices under regulatory controls required for clinical trial use and achieve sufficient throughput scale-up by vertically integrating device fabrication, in-process inspection, sterilization and clean-room packaging capabilities. Positive margin rates associated with contemporary BCS are high (~18%-22.3%), and cause significant strains on patients and the cost of breast healthcare. Meta-analyses of the impact of surgical margins on local recurrence also confirm that negative margins have a positive prognostic effect. Thus, CairnSurgical is well positioned to develop and commercialize a potentially practice-changing approach to BCS that improves clinical outcomes for patients.