Optical biopsy to improve the diagnosis of kidney cancer: a prospective, observational, multicentre, in-vivo study.

Renal biopsies are used in patients with renal mass lesions to diagnose whether
it concerns a malignant or benign mass. In case of malignancy, surgery will be
the following step. However, 7 to 33% of biopsies are non-diagnostic, what can
result in unnecessary surgery (even up to 30% in small renal masses). We
believe that optical biopsy (OB), a new diagnostic tool based on the absorption
en reflection of light in tissues, reduces the non-diagnostic biopsy rate. This
could have a direct impact on the quality of life of the patients that are
therefore scheduled for an unnecessary surgical procedure. Also, concerns about
overtreatment have led to the concept of focal therapy, a selective patient
tailored ablation technique of a lesion, reducing lifetime morbidity and side
effects without compromising life expectancy. For this novel form of treatment,
accurate identification, grading and demarcation of a lesion is crucial and OB
is the ideal platform to provide this approach to an improved cure.

To evaluate the accuracy and adverse events of combined use of minimal invasive
optical coherence tomography (OCT) to differentiate normal tissue from
(different types of) malignant tissue in kidneys.

This is a prospective, observational, blinded, multicentre, in-vivo study in a
cohort of 194 patients with the clinical diagnostics of a renal mass. All
consecutive patients scheduled for nephrectomy, partial nephrectomy or cryo
ablation due to a renal mass will be enrolled in this study until the required
sample size is reached. Inclusion is based on informed consent approval and
conjoint availability of the departments of Pathology and Biomedical
Engineering & Physics (BMEP) at time of surgery. The only interaction with
patients is during biopsy and surgery. Results of OCT and DRS will not
interfere in the regular follow-up according to histopathological diagnosis and
institutional protocol.

The study is roughly divided into three different steps:

First, calibration of the OCT systems will be performed to confirm the tissue
related quantitative optical parameters that are extracted from OCT
measurements. Both systems will be simultaneously calibrated using tissue
mimicking optical phantoms.

Second, optical biopsies will be taken in all of the 194 patients in whom a
solid renal mass was seen by cross-sectional imaging. The optical biopsies,
with a minimum of 5 measurements per biopsy spot, will be obtained. After this
procedure, conventional needle biopsy of the kidney tumors will be obtained
with a minimum of 2 biopsies. These procedures will be repeated in a subgroup
of 30 patiënts during surgical removal of the tumor. This provides control data
on previous findings and evaluates applicability during surgery at the OR.
Outcomes of the optical biopsies are correlated to pathology.

Third, in cases with confirmed malignancy, the discriminating ability of
optical biopsy among the three most common RCC sub types will be blindly
assessed. The previously established protocol will be used and optical biopsy
outcomes will be correlated to pathological findings.

There are no anticipated additional risks for participants since the OCT is a
non-invasive imaging method based on light. However, during the percutaneous
biopsy a slightly larger canule is necessary to access the retro-peritoneal
cavity since the percutaneous needle device has no entrance for an additional
probe such as our OCT probe. During operation, the operation time is prolonged
for only a couple of minutes (max. 5%).