New technology could detect malignant tissue during radical prostatectomy

Researchers have demonstrated that a technique called light reflectance spectroscopy can detect positive surgical margins with 86% accuracy—a finding that could lead to real-time intraoperative tissue analysis during radical prostatectomy, according to a study published in the February 2016 issue of The Journal of Urology.

Currently, no technology exists to rapidly detect positive surgical margins intraoperatively. The standard method used to determine margin status is pathological analysis completed after surgery. But the rate of positive surgical margins found in prostate cancer specimens is high—as much as 38%.

So, researchers have been investigating new and better ways to detect whether malignant tissue is left behind after prostate cancer surgery. A non-invasive method that would accomplish this intraoperatively could significantly impact surgical technique and patient outcomes, the researchers noted.

“We used a novel light reflectance spectroscopy probe to evaluate surgical margins on radical prostatectomy tissue specimens and correlated the findings with pathological examination,” said the study’s lead author Jeffrey Cadeddu, MD, Professor of Urology and Radiology at The University of Texas Southwestern Medical Center, in Dallas, TX.

Light reflectance spectroscopy (LRS) measures light intensity reflected or backscattered from tissue. Because different tissues reflect (backscatter) light at different wavelengths, LRS can be used to identify the characteristic signatures in the spectrum that correlate with those tissues—such as malignant vs. benign tissue. Other studies have investigated LRS for various cancers, but using this technology to examine prostate cancer specimens is a novel one.

For this investigation, Dr. Cadeddu—along with Hanli Liu, PhD, and her team from UT Southwestern Graduate School of Biomedical Engineering—assembled their own LRS system, which included an optical probe, single channel spectrometer, a tungsten-halogen light source, and a laptop computer to gather the data.

Once the device was ready, the researchers enrolled patients with intermediate- to high-risk prostate cancer. Immediately after radical prostatectomy, Dr. Cadeddu and colleagues performed LRS analysis on 17 prostate gland specimens. Each sample was correlated with pathological samples, which were analyzed post-surgery by an experienced genitourinary pathologist. Of the 17 specimens, a total of 11 histologically positive and 22 negative surgical margins were measured.

The researchers determined that LRS predicted positive surgical margins with 85% sensitivity, 86% specificity, and 86% accuracy.

“This study highlights one of a growing number of technology platforms that aim to improve the outcomes of cancer surgery,” said Dr. Cadeddu, who is also the Ralph C. Smith MD Distinguished Chair in Minimally Invasive Urologic Surgery at UT Southwestern. “Further study is required to determine whether such analysis may be used in real time to improve surgical decision-making and decrease the amount of tissue surgeons need to remove.”