The use of SPEctroscopy during Endoscopy for Detection of BiLIary Strictures

Distinguishing benign and malignant biliary strictures is often difficult.
Around 70% of the biliary strictures have a malignant origin, whereas up to 30%
of the strictures were benign. Because of the choice of treatment,
differentiating benign from malign strictures is very important. The routine
work-up consists of obtaining clinical information and abdominal imaging
(ultrasound, CT, MRCP). However, brush cytology and tissue biopsies, acquired
during endoscopic retrograde cholangiopancreatography (ERCP), are usually
necessary for adding more information about the possible diagnosis. Brush
cytology alone yields to a mean sensitivity of 42%, whereas the specificity
approaches 95%. Brush cytology and forceps biopsy combined, yield to an
increased sensitivity between 60-70% in detecting of malignant structures.
Nevertheless, the sensitivity in differentiating benign from malignant biliary
strictures is still not reliable enough and that states the need for improved
techniques. A novel technique in detecting tumor tissue is Single Fiber
Reflectance (SFR) spectroscopy, which could be incorporated in the EUS-FNA
procedure to detect pancreatic masses. It is an optical imaging technique,
capable of extracting reflectance spectra from endogenous chromophores from a
very small tissue volume. In a feasibility study of our group, SFR spectroscopy
showed an accurate correlation between cytology in 9 patients with a pancreatic
mass (3 benign vs 6 malignant). Moreover, the oxygen saturation and bilirubin
concentration differs significantly between normal and malignant tissue. In
this study, the feasibility of SFR spectroscopy incorporated in an ERCP
procedure for distinguishing benign and malignant biliary strictures will be
evaluated by measuring wavelength dependent optical characteristics over a
broad wavelength range (400-1000 nm).

Primary:
- The feasibility of SFR spectroscopy incorporated in an ERCP procedure.
Secondary:
- Determine physiological differences between benign and malignant biliary
strictures, based on the obtained spectra acquired over a broad wavelength
range (400-1000 nm).

Prospective observational single center feasibility study.

No additional risks were expected during participation in this study, besides
the standard risks for ERCP. The optical measurements are performed with
sterile optical fibers. To avoid potential spread of tumor cells to healthy
tissue, measurements are only taken in tissue that will be removed by biopsies.
The total time taken by the measurements is around 5 minutes.