The LightPath® and 68Ga-RM2 in Breast Cancer Study

Overview

This study is a prospective, open-label study to examine the performance of the LightPath® Imaging System using the PET tracer 68Ga-RM2 in patients scheduled for and/or undergoing wide local excision (WLE) with or without sentinel lymph node biopsy (SLNB) or complete axillary lymph node dissection(cALND) for breast cancer with an ER-positive invasive primary cancer. The study consists of 3 sequential groups: Group 1 (N=20 patients): Torso, i.e. base of skull to thighs, PET/CT imaging and axillary gamma probe measurements (using a collimator) of 68Ga-RM2 to: determine the optimal scan time-window post-injection; to extrapolate the optimal dose for resolution against axillary background signal on gamma probe measurements (first 6 patients); and the value of 68Ga-RM2 PET/CT imaging for breast cancer staging (all 20 patients). Group 2 (N=10 patients): Intraoperative LightPath® imaging with 68Ga-RM2 to familiarise site with procedure and interpretation of intraoperative scans,validate the dose and timings determined from Group 1, and optimise LightPath® Imaging parameters such as acquisition resolution and duration. Group 2 scans will acquire LightPath® images of both intact and incised cancer specimens for post-operative standardised, controlled assessment. Group 2 will use the optimal scan time-window and 68Ga-RM2 activity extrapolated from at least the first 6 patients in Group 1. The dose of 68Ga-RM2 will be determined to optimise the intra-operative imaging and axillary gamma probe measurements. Group 3 (N=50 patients): Intraoperative LightPath® imaging with 68Ga-RM2 to measure agreement between LightPath® images and post-operative histopathology. Group 3 scans will acquire LightPath® images of intact and incised cancer specimens for post-operative standardised, controlled assessment. Group 3 will use the optimal scan time-window and 68Ga-RM2 activity extrapolated from the first 6 patients in Group 1 with the optimised imaging parameters, and dose developed from Group 2. The intraoperative LightPath® Images will be used to inform the surgeons about detectable residual cancer in an attempt to achieve better guided cancer surgery and complete tumour excision with clear WLE resection margins The study site will use the local criteria considered standard of care to guide decisions to act on positive margins. Lightpoint Medical will provide guidance to act on LightPath® Images in the Instructions forUse (IFU). It will be at the Investigator's discretion to choose whether to act based upon the intraoperative LightPath® Images. In Group 3,the resection margin status of the WLE specimen, cavity shavings (if any) and the metastatic status of axillary (sentinel) lymph nodes as measured with the LightPath® Imaging System will be compared with histopathology results. A positive margin on histology will be defined as * Invasive carcinoma: positive: ink on tumour; close: \<1mm; negative ≥1mm * Ductal carcinoma in situ (DCIS)or pleomorphic lobular carcinoma in situ (LCIS) (if present): positive: ink on tumour; close: \<2mm; negative ≥2mm.