Fox Chase Researchers Examine Alternative Methods of Specialized Imaging Scans for Kidney Masses

Robert Wang, MD

In a study presented today at the American Urological Association (AUA) Annual Meeting 2024, researchers from Fox Chase Cancer Center showed that using numerical cutoffs as opposed to radiologist-read CT scans to determine whether a mass was likely cancerous did not yield more accurate results.

This work served as a follow-up to a previous study done by former Fox Chase urology fellow Jared Schober, MD. Schober looked through data from Fox Chase regarding the results of 99mTC-Sestamibi SPECT/CT, a special type of CT scan sometimes used to see if a kidney mass is cancerous or not.

Schober’s study, which was detailed in a 2023 issue of the Journal of Urology, revealed a notable discrepancy in scans used to assess suspicious kidney masses — a substantial number of predicted malignancies were, in fact, benign. These results underscore the importance of rigorous evaluation of the test’s effectiveness in practical settings before it is established as a standard diagnostic procedure for kidney masses.

“One difference between Dr. Schober’s study and other studies on 99mTC -Sestamibi SPECT/CT was that in his study an experienced radiologist decided whether or not the scan suggested cancer or not,” said Robert Wang, MD, lead author on the new study and a second-year fellow in the Department of Urology at Fox Chase.

“Other studies used numerical cutoffs based on how ‘bright’ a mass was to make the call. In this follow-up study, we applied the numerical cutoffs used by other studies to our own scans. The idea was that by taking human judgment out of the scan interpretation process, we would get more consistent and possibly more accurate scan results,” he said.

In doing this, Wang said they found that using numerical cutoffs did not change the results significantly and that radiologist-read scans were in some ways more accurate. This study was important in showing that the difference between Schober’s findings and earlier studies wasn’t due to how the scans were being interpreted.

Wang said that while these numerical cutoffs improved the likelihood that a mass classified as noncancerous was indeed benign, it also increased the number of tumors erroneously classified as cancerous when they too were likely benign. He added that more work is necessary to determine what role 99mTC-Sestamibi SPECT/CT might have in routine clinical practice.

“Having our findings chosen for presentation at AUA speaks to the strength of the research mentorship here at Fox Chase. Through working with experienced and renowned mentors such as Dr. Alexander Kutikov, as well as building off of the impactful research of a previous fellow, I was able to make a small but meaningful contribution to this area of research,” said Wang.

The study, “Limited Utility of Quantitative Thresholds on 99mTC-Sestamibi SPECT/CT for Distinguishing Renal Cell Carcinoma From Oncocytic Renal Masses,” was presented during a podium session at the AUA meeting, which is being held May 3-6 in San Antonio, Texas.