| When thinking about cancerous tissue morphology, many times what comes to mind is a large growth of abnormal tissue that is somewhere between tens of microns and tens of centimeters in size. While these large scale changes are the most dramatic manifestation of cancer morphology, they exemplify only the final steps of a protracted process that may have taken course over multiple decades. On the other end of this process, the earliest and most subtle stages of cancer development are well-described under the concept of field carcinogenesis: the idea that a number of genetic/epigenetic changes located throughout an organ lead to ultra-structural and micro-vascular changes that create a 'fertile field' from which future cancer growth can emerge. The implications of field carcinogenesis are two-fold: First, it provides a glimpse into cancer development at the earliest stages possible. Such information can form a basis from which later cancer stages can be better understood. Second, it can be exploited to detect the presence of cancer at early time-points where prognosis is vastly improved.;Given that many of the changes in field carcinogenesis are smaller than the diffraction limit of light, the tissue appears microscopically normal. Thus, in order to optically detect such changes, sophisticated instrumentation and analysis methods are needed. In this work, we review the use of enhanced backscattering (EBS) spectroscopy for targeting the ultra-structural and micro-vascular alterations associated with field carcinogenesis. We begin with a review of the optically-relevant changes occurring in field carcinogenesis and how they give rise to the scattering and absorbing signal observed in EBS. Next, we detail the experimental and numerical methods used to accurately measure and simulate EBS. Finally, we conclude with a discussion of the location and nature of the changes measured ex-vivo and a confirmation of the diagnostic potential for in-vivo application. |
