In vivo identification of rectum and colon carcinoma during surgery using optical spectroscopy techniques

Clinical problem:
A tumour free circumferential resection margin (CRM) is an important prognostic
factor for disease free and overall survival after a complete resection of
colorectal cancer. A positive CRM is associated with an increased incidence of
local recurrence and lower overall survival. Local recurrence is a disabling
disease, with severe symptoms such as pain, faecal voiding and mechanical
obstruction. In locally advanced and distal rectal tumours, a positive CRM is
found in 20-30% of the procedures. Extending the resection margin reduces the
risk of a positive CRM, but increases the risk of morbidity due to damage to
surrounding vital structures.
Optical spectroscopy:
In recent years promising advances in cancer treatment imaging have been made
with optical spectroscopy. By illuminating specific tissue with a selected
light spectrum and subsequent analysis of the characteristic scattering,
absorption and luminescence patterns, it is possible to obtain an *optical
fingerprint* of the tissue and to discriminate between benign and malignant
tissue.
Incorporation of optical spectroscopy during colorectal surgery could improve
the accuracy of the procedure. In recently performed ex vivo optical
spectroscopy measurements of colorectal tissues, we observed an overall
accuracy of 92% for differentiation between normal and tumour tissue. To
further develop this technique for surgical applications, such as surgical
margin detection, in vivo validation of tissue differentiation is necessary.

The goal of this pilot study is to calculate the sensitivity and specificity
for discriminating tumour and benign tissues in vivo in colorectal cancer
patients based on optical spectroscopy measurements. The secondary goal of this
study is to calculate the spectral differences between in vivo and ex vivo
measurements and the difference in the biological parameters (i.e. fat content,
blood oxygenation, etc.) that are extracted from the spectral information.

This study is designed as an observational study.

Participation in the study will not involve additional visits to the hospital
for the included patients. Informed consent will be obtained prior to the
procedure.
The total time for all measurements will take no longer than 10 minutes.
Furthermore, it is highly unlikely that additional damage or discomfort will
occur during the measurements. The normal surgical procedure will not be
altered in any way, other than the additional time for the measurements and
possible biopsy of the normal tissue. The surgeon will be blinded to the
spectroscopy results.