Abstract P1-11-06: Learning curve for the SAVI SCOUT breast localization and surgical guidance system
Authors: Shukla SC , Shivers SC , Mattingly A , Russell S , Mehindru A , Carter E , Cox CE 
Published: March 2017

Background: The gold standard for localizing non-palpable breast lesions for surgical excision is wire localization (WL). Multiple disadvantages for WL include complicated scheduling and migration of the wire after placement. Radioactive seed localization (RSL) mitigates these disadvantages, but regulatory requirements regarding radiation limit more universal adoption. The SAVI SCOUT surgical guidance system (an FDA cleared medical device) eliminates the drawbacks of WL without the regulatory requirements of RSL. SCOUT utilizes electromagnetic wave technology and infrared light to provide intra-operative guidance during surgical excision. The purpose of this study is to describe the learning curve associated with adoption of this new technology.

Method: An IRB-approved prospective, single-arm, multi-site trial enrolled women with non-palpable breast lesions requiring localized surgical excision. After informed consent, a radiologist or surgeon used imaging guidance to implant the SCOUT reflector into the target lesion. Intraoperatively, the surgeon used SCOUT for localization of the reflector and removal of the target lesion. We evaluated the association of several independent variables with respect to successful localization and surgical excision including: tumor side, tumor quadrant, distance of reflector from the skin, and the number of SCOUT localized breast excisions performed by operating surgeon up to the 1st five cases. We studied the relationship between these independent variables and the following dependent variables: reflector detection post-placement, reflector detection pre-incision, and reflector localization post-incision.Statistical analysis utilized the z-test to perform a two-sided test of equality at an alpha level of 0.05 with adjustment for multiple comparisons by the Bonferroni method. T-tests were used to perform two-sided tests of equality for numeric variables.

Results: Across 11 institutions, 16 surgeons performed a total of 153 surgical excisions. Overall success rates of reflector detection pre-incision and post-incision were 98% (150/153) and 99% (151/153), respectively. The reflectors were successfully removed in 100% (153/153) of cases. Difficulty with reflector detection immediately post placement was significantly associated with reflectors more than 4 cm (P=0.034) or 5 cm (P=0.007) from the skin, or the procedure being the 1st SCOUT case by the operating surgeon (P=0.036). Operating surgeons performing their 1st SAVI localization procedure were significantly associated with difficult reflector detection post-incision (p=0.044). Subsequent procedures, up to the first five SCOUT localizations, noted no significant difficulty with reflector detection.

Conclusions: The SAVI SCOUT surgical guidance system is a viable surgical localization procedure for non-palpable breast lesions. Surgeons were 100% successful at removing the reflectors during surgical excision. Difficulty with reflector detection was not noted after the surgeon's 1st SCOUT procedure. Overall, it appears the learning curve for reflector placement and localization for non-palpable breast lesions is relatively short. However, depth of the reflector in relation to skin likely affects reflector detection during this early learning period.

Citation Format: Shukla SC, Shivers SC, Mattingly A, Russell S, Mehindru A, Carter E, Cox CE. Learning curve for the SAVI SCOUT breast localization and surgical guidance system [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-11-06.