A Novel Deep Raman Spectroscopy Platform for Non-Invasive In-Vivo Diagnosis of Breast Cancer

Recently, we have pioneered a portfolio of revolutionary optical technologies in the area of laser spectroscopy, namely deep Raman spectroscopy, for non-invasive molecular probing of biological tissue. The developments have the potential of making a step-change in many fields of medicine including cancer diagnosis. The techniques comprise spatially offset Raman spectroscopy (SORS) and Transmission Raman (both patented by the applicants). The methods are described in detail in a tutorial review: http://pubs.rsc.org/en/content/articlelanding/2016/cs/c5cs00466g. There is an urgent clinical need for early objective diagnosis and prediction of likely treatment outcomes for many types of subsurface cancers. This is not addressed by existing technologies. There are numerous steps along the cancer clinical pathway where real-time, in vivo, molecular specific disease analysis would have a major impact. This would significantly reduce needle biopsy, in around 80% of those recalled following mammographic screening this step is unnecessarily - ie leading to the diagnosis of benign lesions. Our novel approach would allow for more accurate and immediate diagnosis in conjunction with mammography at first presentation by improving screening or surveillance techniques, leading to earlier diagnosis and better treatment outcomes. Secondly it would allow surgical margin assessment and treatment monitoring in real-time and thirdly identification of metastatic invasion in the lymphatic system during routine surgery. There are numerous other areas where a rapid molecular analysis of a tissue sample in the clinic or theatre environment would allow improved clinical decision-making, for example when pre- operatively staging the disease and particularly when non-invasively monitoring tumour response during chemo/radiotherapy. Clearly these approaches would be beneficial to the patient by reducing cancer recurrence rates; but also by minimising the numbers of invasive procedures required, thus reducing costs and patient anxiety.
Raman spectroscopy is a highly molecular-specific method, which itself has proven to be a useful tool in early epithelial cancer diagnostics, although in its conventional form it has been restricted to sampling the tissue surface of much less than 1 mm deep. The new technology unlocks unique access to tissue abnormalities of up to several cm's deep, i.e. at depths one to two orders of magnitude higher than those previously possible with Raman.

Following on from our previous project, where we were able to demonstrate conceptually a ~100x improvement in signal recovery compared to our early feasibility work, we are now able to rapidly develop a platform for real-clinical tools using this approach. We propose to make major breakthroughs in this area and advance diagnostics particularly focussed on breast cancer and lymph node metastasis initially as focused case studies and then potentially applied to prostate cancers (outside the scope of this proposal). This will be explored as a joint cross-disciplinary research venture between Profs Stone and Matousek, the two key researchers in this area. We now seek funding to progress this work in a timely manner by developing a novel medical diagnostic platform of major societal impact. We propose to bring together key players from multidisciplinary areas covering physical sciences, spectroscopy, radiology, cancer diagnostic and therapeutic surgery, and histopathology to exploit all of the relevant skills and develop a critical mass of expertise to tackle these challenging issues.

Here we plan to develop the next generation of diagnostic systems for breast cancer diagnosis. A flexible diagnostic platform that could be used for various clinical needs in the detection, grading, staging and treatment of breast cancers. This will be facilitated by translating the SORS and Transmission Raman spectroscopy from its current pharmaceutical and security application fields into the medical arena. Due to the complexity of the biological tissue and the presence of inherent low level analytes/markers a dramatically higher instrumental sensitivity and penetration depth is required for medical applications. We have now demonstrated the concept experimentally with ~100x improvement in signal recovery from 4 cm thick tissue phantoms and propose to develop this technology for in-vivo scanning of human breast tissue. The new platform promises to unlock a range of novel medical applications and have a knock out effect also on other areas where high sensitivity is required.
Successful completion of this project will pave the way for establishing the new technique of deep Raman spectroscopy in the clinical environment, to enable its capability to probe disease in real- time, utilising light/tissue interactions to provide a reliable measure of the benign or malignant state of breast lesions; to non-invasively assess cancer margins at the operating theatre and to non- invasively assess breast lymph nodes for the presence of metastatic cancer cells.

ADJUNCT TO CURRENT DIAGNOSTICS
The long term potential is highly significant. We expect during this project to be able to develop a device for use as an adjunct to current diagnostic approaches, such as X-ray mammography (or ultrasound), which is highly sensitive to cancerous lesions but provides very poor specificities, ie picking up many non-cancerous conditions. The deep Raman molecular composition signal would be expected to provide the required chemical specificity to overcome this major limitation of the screening programme if Raman signals could be recovered from such depths in vivo. Furthermore, optical radiation is inherently safe at the low intensities we propose to use, whereas X-ray screening using ionising radiation can in its own right induce cancers in the screened population. We would expect to have a significant impact on reducing the numbers of patients with benign lesions recalled for additional tests and needle biopsies. In addition the deep Raman technique could potentially be utilised to monitor patients diagnosed with lower grades of ductal carcinoma in situ: to safely detect any changes towards higher grade DCIS or invasive malignancy. This may lead to increased mammographic screening effectiveness and reduced over treatments.

SURGICAL TOOL
Here we will develop the technology sufficiently far to enable the use of DRS in a flexible handheld probe system. The technique when proven to be applicable to the soft tissue margins and identification of metastatic lymph nodes in the breast can then in future easily be applied to other solid cancers, such as the prostate. Furthermore, other soft tissue lesions could be explored or risky surgical margins in sensitive organs such as the brain could be probed and target areas identified.

FUTURE MONITORING AND MEDIATING THERAPEUTICS
The invention of Surface Enhanced Spatially Offset Raman spectroscopy (SESORS) by the applicants in collaboration with the Graham/Faulds group at Strathclyde has led to the first demonstrations that we can probe the unique signals provided by labelled surface enhanced Raman nanoparticles buried within tissues, providing specific signals from molecular targets at depth. This could lead to multiplexed imaging of nanoparticles in vivo in the distant future too.

In addition these novel approaches can facilitate information on chemical specific temperatures which may allow tumour physiology studies and impact of therapeutics to be monitored in situ.