Spectroscopic biopsy of the prostate
Prostate cancer is the most frequently occurring cancer in men, with an estimated 17000 patients in the Netherlands in 2020 (26% of all cancers). Due to improvements in early diagnostic techniques small tumors occupying less than 5-10% of the prostate volume can now be detected. These tumors are usually present at one location (unifocal) and are confirmed with physical biopsy and subsequent histopathological grade (aggressiveness) evaluation. Because of unclear demarcation of the lesion on presently available imaging techniques a biopsy-sampling protocol is required, in which 10-20 core-needle biopsies are taken. Current treatment of prostate cancer is based on systemic medication or radical surgical procedures in which the prostate is (partially) removed which comes with considerable side effects such as erectile dysfunction and incontinence. These concerns have led to the development of focal (i.e. localized) therapy, a selective ablation technique using for example cryosurgery, reducing lifetime morbidity and side-effects without compromising life expectancy. The success of this treatment strategy relies on accurate identification, grading and demarcation of the lesion. This is challenging using the current diagnostic techniques.
We propose to solve this clinical problem using spectroscopic biopsies of the prostate, using a synergistic application of optical coherence tomography (OCT) and fiber optic spectroscopy (DPS), through biopsy needles that are placed under ultrasound guidance. Combined in a single device, these state-of-the-art fiber optic technologies will be delivered through a 3 French (Ø = 1mm) needle, minimizing damage to the prostate. The PROSPECT optical biopsy shows the morphology and architecture of the tissue at micrometer scale resolution (OCT) complemented by information on tissue function, e.g. cellular organization derived from light scattering (OCT/DRS), microvascular properties such as perfusion (OCT), vessel density, oxygen saturation (DRS) and biochemical composition, e.g. fractions of water, fat, bilirubin, beta-carotene and hemoglobin (DRS). With PROSPECT, the morphological and biochemical changes occurring during prostate cancer development can be quantified, enabling real time lesion detection and tumor grading. When a lesion is detected by PROSPECT, a physical biopsy sample can be obtained by the operating physician to confirm pathology.
WP2.2.1: Instrumentation (AMC)
We will make a catheter-based side looking spectroscopic probe. Current technology (DPS) requires contact between tissue and optical fiber. The novel probe will look sideways through the catheter. Side looking OCT catheters have been developed in the past by the AMC group. We will integrate OCT focusing optics with the optical fiber and combine the OCT measurement and the spectroscopic measurement through the same probe. We will develop a device for scanning the tissue in 3D using a helical scan pattern (rotating and retracting the probe simultaneously).
WP2.2.2: Data analysis (Erasmus MC)
We will locate the exact positions of the catheters within the prostate to trace the location of the fibers within the catheters at each point in time. We will combine the OCT information in the analysis of the spectroscopic measurements (e.g. scattering values, blood vessel locations) and create a 3D map of optical properties from the combined OCT and spectroscopic measurements.
WP2.2.3: Validation and demonstration (Erasmus MC AMC)
We will test the setup in optical phantoms with known optical properties and demonstrate the feasibility of the approach in a small series of animal experiments (3 dogs) at ErasmusMC. Finally we will perform the pre-clinical evaluation in a small group of patients that are already scheduled for radical prostatectomy in the AMC. When possible these measurements will be performed prior to surgery; in any case immediately after resection.