Optical coherence tomography (OCT) shows promise in helping urologists detect cancerous tissue, especially in the ureter, according to Jean de la Rosette, MD, who presented the annual Société Internationale d’Urologie (SIU) Lecture Monday morning at AUA2017.
“The strength is that [OCT] is a real-time imaging modality with a high diagnostic yield. And while it’s not always noninvasive, it’s minimally invasive in the majority of cases,” said Dr. de la Rosette, professor in the Department of Urology at AMC University Hospital in Amsterdam, the Netherlands.
OCT was first used in ophthalmology before being introduced in urology in the late 1990s. However, biopsy remains the primary diagnostic tool for urological cancers.
“Taking a biopsy has an invasive nature and the possible risk of complications. With the increasing number of patients at high risk and using anti-clotting drugs, this risk of complications is significant,” Dr. de la Rosette said. “In addition, the histopathology needs some time for preparation. And in some of the cases where we take biopsies, the diagnostic yield is relatively low.”
OCT is the next logical step for diagnosing urological cancers because of its minimally invasive nature, he argued. There are currently three commercially available devices, including one that is handheld.
“This technology may in some cases replace tissue biopsies or may be adjuvant to histological biopsies,” Dr. de la Rosette said.
He described OCT as the optical analog of ultrasound. Depending on the tissue density, the light is scattered back and appreciated by the system measuring the returning OCT signal.
“For malignant tissues you can look at different grades or different types of abnormalities, such as in kidney cancer,” he said.
Most of the research on the use of OCT in urology has focused on bladder cancer, but research also exists on its use in prostate, ureter, kidney and penile cancer. Dr. de la Rossette discussed the research in each of these areas, noting that most of the studies have been small in scale. But overall, the research indicates that OCT has good sensitivity and specificity, he said.
Dr. de la Rossette said OCT may be most promising for the ureter.
In a study published in The Journal of Urology® of 26 patients who underwent radical nephroureterectomy, researchers reported the sensitivity and specificity of OCT were very high for diagnosing whether a tumor existed and whether it was high grade or low grade. For patients with carcinoma in situ in particular, OCT scans clearly differentiated between normal urethral lining and carcinoma in situ.
“We are continuing these studies and I think for upper tract tumors this technology holds a lot promise,” Dr. de la Rossette said. “This is something you are going to incorporate into your practice in the very near future.”
While OCT technology looks promising, it is invasive in some cases and may not be ideal for all patients. Also, imaging depth is limited to 2 mm.
“However, as illustrated, for the ureter this is ideal,” Dr. de la Rossette said.
The biggest roadblock to more widespread acceptance of OCT is the limited data. For example, only two studies have been published on penile cancer, with limited ongoing research.