Biophotonic Detection Of Increased Microvascular Blood Content (Fibs) As A Marker Of Field Carcinogenesis Detection: Potential Adjunctive Technology For Colonoscopy

Introduction: Colonoscopic screening has been somewhat hampered by issues such as polyp miss rate (∼25-50%), frequent mucosal obscuration from poor preps and need for "optical biopsy". Our group focuses on bridging advances in biomedical optics to clinical practice (Nature 2000, Nat Med2001). We have developed a novel optics technology, 4D-ELF (Gastro 2004) which allowed heretofore unprecedented detection of microvascular blood content. In animal models, 4D-ELF allowed us to detect an early increase in blood supply (EIBS) in the microscopically normal colonic mucosa at risk for tumorigenesis thus serving as a marker of the “field effect” (Gut 2005, FEBS 2007). We aimed to assess whether EIBS detection could have potential clinical applications. Methods: We developed a novel endoscopically compatible 4D-ELF probe and measured EIBS from the cecum, mid-transverse, and rectum. If lesions were found, measurements were taken from the polyps site and 10 cm away. 222 patients undergoing colonoscopy were recruited. Results: EIBS in the endoscopically-normal mucosa was elevated in patients harboring neoplasia with the magnitude mirroring proximity to adenoma (figure). Indeed, rectal EIBS elevation could determine the presence of advanced adenomas elsewhere in the colon with excellent accuracy (AUROC=0.91). While EIBS was detected in hyperplastic polyps tissue, there was no increase in the surrounding mucosa (in contrast with adenomas). Conclusions: Identification of field effect by optical detection of EIBS can potentially aid colonoscopy in 3 scenarios: 1. Rectal assessment if mucosal visualization was incomplete (e.g. poor prep or failure to intubate cecum) to determine whether colonoscopy needs to be repeated. 2. Mapping EIBS gradient as a guide to polyps (improved detection) 3. Differentiate adenomas from hyperplastic polyps through EIBS analysis in adjacent mucosa (optical biopsy).