Intra-operative EMI-137 fluorescence imaging in Breast Cancer

  • Research type

    Research Study

  • Full title

    A pilot study of EMI-137 fluorescence imaging to improve the accuracy of surgical excision in patients with Breast Cancer

  • IRAS ID

    114799

  • Contact name

    Anand David Purushotham

  • Contact email

    Ea-Purushotham@kcl.ac.uk

  • Sponsor organisation

    King's College London/Guy's and St.Thomas' Foundation Trust

  • Eudract number

    2014-003554-13

  • Duration of Study in the UK

    1 years, 4 months, 30 days

  • Research summary

    Research Summary

    Wide local excision (WLE) is the type of surgery that is used most often to surgically remove breast cancer. Sentinel Lymph Node Biopsy (SLNB) is a surgical procedure that is done to check if cancer cells have spread to the lymph nodes. There is a lack of techniques that can be used during an operation to check whether all cancer cells have been removed. Therefore, about 1 in 4 breast cancer patients that have a WLE and/or SLNB need to have a second operation to remove remaining cancer cells.

    Repeat surgery has several negative results: poorer cosmetic outcome, delayed adjuvant (post surgery) treatment; increased emotional distress and increased costs. Hence, there is a clear need for developing new techniques to help surgeons remove all cancer cells during the first operation, thus reducing the need for further surgery.

    The aim of this research is to test a new technique that may help surgeons find and remove all cancer cells during surgery. c-Met is a protein found on cell surfaces, including the surfaces of breast cancer cells. The new technique uses a fluorescent tracer (called EMI-137 Injection) which binds to c-Met expressing tumours. The tracer will be injected into patients before surgery and using a fluorescence imaging camera, called the Clinical Spectral Imager, surgeons will locate and remove the cancer cells during surgery. This could lead to complete removal of the cancer and reduce the number of re-operations.
    The study will be an exploratory phase I/II, single centre, study. We are aiming to recruit 40 breast cancer patients at Guy’s and St Thomas’ NHS Foundation Trust.

    Summary of Results

    Introduction EMI-137, previously known as GE-137, is a c-Met targeting peptide coupled with the fluorescent cyanine dye Cy5.7. c-Met is (over)expressed in a range of solid cancers including breast cancer and oral squamous cell carcinoma (OSCC). The aim of this study was to assess the feasibility of EMI-137 fluorescence imaging for intraoperative assessment of tumour margin status in breast and oral cancer.

    Methods
    Administration of EMI-137
    On the day of surgery, patients were admitted to the Guy’s Hospital Clinical Research Facility for an intravenous injection of EMI-137 and monitoring, as per the study protocol. Patients were taken from the Clinical Research Facility directly to the operating theatres for their surgery.

    Surgery
    Surgical procedures were performed as per standard-of-care. A wide local excision (WLE) was performed of the main tumour. Following excision, all specimens were imaged in the operating theatre using a fluorescent imaging system.

    Analysis
    Areas on the surgical specimens showing a bright fluorescent signal were regarded as positive and compared to the standard-of-care post-operative histopathology results, where invasive cancer <1mm or DCIS <2mm of the excision margin was considered a positive margin.

    Results
    Breast cancer & oral squamous cell carcinoma Between 09 November 2015 and 14 March 2016, 4 breast cancer and 2 OSCC patients were recruited. The six included patients were injected with EMI-137 prior to surgery and scanned intraoperatively. Imaging of the intact wide-local excision (WLE) specimens showed no fluorescent signal at the margins for all patients. Following incision of the specimens, effectively bisecting the tumour, a positive fluorescent signal was noted in one breast cancer specimen (Figure 1).

    Figure 1. An incised invasive breast cancer specimen depicted on a. white light image b. fluorescent image and c. post-acquisition overlay of image a. and b. Image a. and b. were acquired using the Clinical Spectral Imager (CSI). The figure shows a clear correspondence between the visually identifiable tumour tissue and the fluorescent signal.
    Post-operative histopathology assessment of the surgical specimens showed that none of the OSCC patients and 1 of the 4 breast cancer patients expressed c-Met, yet only ‘mild’, explaining the negative imaging results for the other patients. This indicated a need for pre-surgery c-Met testing, to select eligible patients.

    Tissue microarrays
    As in literature no consensus was found for the c-Met overexpression criteria1, 2, 3, a quality assessment on 172 tissue microarrays (TMAs) of various types and grades of breast cancer was performed to determine the cut-off value for c-Met positivity and to assure the efficacy of histopathology assessment. SP44, a selective and widely used rabbit monoclonal c-Met antibody from Ventana Medical Systems Inc., was used for the immunohistochemical evaluation of c-Met expression4–6.
    A c-Met scoring system was devised where an Allred score of ≥3 would constitute as c-Met positive. Patients who tested positive for c-Met on their core biopsy would be included in the study.

    Study amendments
    Due to significant changes within the Oral Surgery department at the institution, the OSCC patient cohort was removed from the study.
    To further maximise the study yield, a change in the EMI-137 regimen – 2 different dosages (0.02 and 0.13 mg/kg body weight) and 2 different imaging time points (2-4 hours and 4-6-hours post-injection) – and a bespoke fluorescence imaging system, the Quest Spectrum Platform™, were implemented following regulatory approval of the substantial amendments to the study documentation.

    Breast cancer WLE and lymph nodes
    After recommencement of the trial on 23 October 2019, 13 eligible patients were identified and approached. All patients consented to participate in the study. Six patients had a c-Met positive tumour. Out of these 6 patients, 5 had to be excluded for various reasons i.e., changes to the treatment plan (n = 2), surgery date outside the scope of the trial (n = 2), unfit for surgery (n = 1). Ultimately, one patient was included in the study before recruitment was halted on 31st December 2019 due to expiry of the EMI-137 shelf-life.

    Wide local excision specimen
    A strong green signal was observed at the anterior, antero-medial and the inferior margins on fluorescent imaging of the wide local excision (WLE) specimen of the tumour (Figure 3). The lateral margin (L, Figure 3) did not show any green-fluorescent light, indicating the absence of any tumour cells close to the margin. Comparison with the official histopathology report showed concordance between histopathology and EMI-137 fluorescence assessment for all margins (Table 1). Moreover, it became apparent that EMI-137 imaging is sensitive to both invasive and ductal carcinoma in situ (DCIS). The latter is the main cause of involved margins in breast-conserving surgery.

    Lymph nodes
    A total of 3 axillary lymph nodes were surgically excised and subsequently underwent EMI-137 fluorescence imaging intraoperatively. None of the lymph nodes emitted a fluorescent signal (Figure 4). A faint green-fluorescent light was observed from the specimens and the empty background (Figure 4 top-right corner) of the first image originate from the imaging system’s laser reflecting of fluid and plastic, respectively. The fluorescent signal from a reflection is substantially weaker than the optical signal from EMI-137, as can be seen by comparing the signal intensities from Figure 3 and Figure 4. During imaging, the optical signal from reflection was easily distinguishable from the real EMI-137 signal.
    Practicality
    The footprint of Quest Spectrum Platform™ was small, the large castor wheels made it easily manoeuvrable, and the multi-jointed arm made the camera very agile. As the imaging system provided real-time images, there was not time delay due to acquisition times. Even in full-ambient light the observed fluorescent signal intensity was strong and therefore clearly distinguishable. In all, image acquisition and interpretation were very intuitive, allowing the operating surgeons to quickly assess the excision margins.

    Safety
    No adverse events were reported, either device or drug related. None of the patients reported any side-effects.

    Conclusion
    Overall, the results of intraoperative EMI-137 fluorescence imaging for the assessment of excision margins were promising. The areas of strong fluorescent signal correspond well with involved excision margins as determined on routine histopathology assessment. Out of the 3 involved excision margins, 2 contained DCIS. The in-situ disease was also detected by our technique. Though no definitive conclusions can be drawn due to the small number of recruited patients for breast (n = 5) and oral cancer (n = 2). Moreover, 7/14 (50%) of the recruited patients in this study were c-Met positive on core biopsy, yet merely 2 of these patients were included in the study for various – medical and practical – reasons. For all staff involved, intraoperative EMI-137 fluorescence imaging using the Quest Spectrum Platform™ was intuitive, real-time, fast, and had a minimal impact on the normal clinical pathway.
    References
    1. Kim YJ, Choi JS, Seo J, et al. MET is a potential target for use in combination therapy with EGFR inhibition in triple-negative/basal-like breast cancer. International Journal of Cancer. 2014;134(10):2424-2436. doi:10.1002/ijc.28566
    2. Edakuni G, Sasatomi E, Satoh T, Tokunaga O, Miyazaki K. Expression of the hepatocyte growth factor/c-Met pathway is increased at the cancer front in breast carcinoma. Pathology International. 2001;51(3):172-178. doi:10.1046/j.1440-1827.2001.01182.x
    3. Garcia S, Dalès JP, Charafe-Jauffret E, et al. Poor prognosis in breast carcinomas correlates with increased expression of targetable CD146 and c-Met and with proteomic basal-like phenotype. Human Pathology. 2007;38(6):830-841. doi:10.1016/J.HUMPATH.2006.11.015
    4. Ren X, Yuan L, Shen S, Wu H, Lu J, Liang Z. c-Met and ERβ expression differences in basal-like and non-basal-like triple-negative breast cancer. Tumor Biology. 2016;37(8):11385-11395. doi:10.1007/s13277-016-5010-5
    5. Kwak Y, Kim S ik, Park C kee, Paek SH, Lee S tae, Park S hye. C-MET overexpression and amplification in gliomas. 2015;8(11):14932-14938.
    6. Xu Y, Peng Z, Li Z, et al. Expression and clinical significance of c-Met in advanced esophageal squamous cell carcinoma. BMC Cancer. 2015;15(1):6. doi:10.1186/s12885-014-1001-3

  • REC name

    London - Chelsea Research Ethics Committee

  • REC reference

    15/LO/0029

  • Date of REC Opinion

    12 Mar 2015

  • REC opinion

    Further Information Favourable Opinion