Abstract P2-12-05: Real-time, intraoperative detection of residual breast cancer in lumpectomy cavity margins using the LUM imaging system: Results of a feasibility study
Authors: Lanahan CR , Gadd MA , Specht MC , Ferrer J , Tang R , Rai U , Merrill AL , Biernacka A , Brachtel E , Smith BL 
Published: February 2018

Background: Obtaining tumor-free margins is critical for local control in breast conserving surgery. Currently, 20-40% of lumpectomy patients have positive margins that require surgical re-excision. We assessed the LUM Imaging System for real-time, intraoperative detection of residual tumor in breast cancer patients. The LUM System has the particular advantage of assessing in vivo lumpectomy cavity walls rather than excised specimens, to enable more accurate excision of residual tumor.

Methods: Lumpectomy cavity walls of patients undergoing lumpectomy for invasive breast cancer or ductal carcinoma in situ (DCIS), were assessed intraoperatively using the LUM Imaging System (Lumicell Inc., Wellesley MA). LUM015, a cathepsin-activatable fluorescent agent, was given IV 4±2 hrs prior to surgery. Areas of fluorescence generated at potential sites of residual tumor in lumpectomy cavities were evaluated with a sterile hand-held device, displayed on a monitor, excised and correlated with histopathology.

Results: In vivo lumpectomy cavities were imaged with the LUM Imaging System in 60 breast cancer patients. 5 were imaged without dye. 55 received LUM015 dye preoperatively and were scanned intraoperatively. Median age was 60 years (range 44-79). Mean tumor size was 1.2cm (0.06-3.5cm) with 71% invasive cancers, 29% DCIS. The test set included 569 cavity margin surfaces assessed intraoperatively and excised. Image acquisition for each margin took approximately 1 second. The LUM Imaging System showed 100% sensitivity and 73% specificity for detection of tumor &lt;2mm from the margin. Invasive ductal cancer (IDC), invasive lobular cancer (ILC) and areas of DCIS 1mm in size could be identified. 8 patients had positive margins on standard histopathology analysis (Table). The LUM System correctly identified all positive margins identified by standard histopathology and correctly predicted negative re-excisions in 2 of 8 patients. There were no serious adverse events. 1 patient had extravasation of LUM015 at her injection site with temporary blue skin staining but no other complication.

Conclusions: The LUM Imaging System allows real-time identification of residual tumor in the lumpectomy cavity of breast cancer patients. No sites of residual tumor were missed. Additional studies are underway to optimize this approach for reducing positive margins and second surgeries in breast cancer patients.

Table: Margin results in 8 patients with positive margins on initial lumpectomy specimenPositive lumpectomy margin histopathologyLUM cavity wall result (+/- for tumor)Tumor found at re-excisionDCIS++DCIS+-DCIS++IDC++ (Mastectomy)ILC++ (Mastectomy)DCIS+-IDC--DCIS--

Citation Format: Lanahan CR, Gadd MA, Specht MC, Ferrer J, Tang R, Rai U, Merrill AL, Biernacka A, Brachtel E, Smith BL. Real-time, intraoperative detection of residual breast cancer in lumpectomy cavity margins using the LUM imaging system: Results of a feasibility study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-12-05.