Dr Wang on the Limited Utility of Quantitative Molecular Imaging Thresholds in RCC

Robert Wang, MD, a urology fellow at Fox Chase Cancer Center, discusses the presently limited utility of using molecular imagining with quantitative thresholds in distinguishing renal cell carcinoma (RCC) from oncocytic renal masses.

During the 2024 American Urological Association Annual Meeting Wang and coauthors presented findings from a retrospective study of 78 patients who underwent 99mTc-sestamibi single-photon emission CT/x-ray CT, a nuclear imaging technique that utilizes a mitochondria-targeting tracer to distinguish RCC from oncocytic renal masses. Study authors found that the use of quantitative hot and cold target-to-background ratio cutoffs of 0.46 and 0.6 improved the negative predictive value of the approach to 89% and 88%, respectively, from a qualitative baseline of 80%. However, the false positive rates for the respective cutoffs were 23.1% and 3.8%, a significant increase from the 1.9% observed with qualitative interpretation by a radiologist.

Wang notes that the findings from this single-center study at Fox Chase should not dampen the general enthusiasm around the use of molecular imaging in RCC. The approach still displays great promise, with the potential to allow patients to avoid unnecessary surgeries by identifying a mass as benign early in the treatment process, Wang says. This benefit will go a long way towards reducing the cost of care for patients and payers, as well as improving patient quality of life by reducing unnecessary pain, suffering, and anxiety for individuals who may not have cancer at all, Wang explains.

Additionally, clinicians must use caution when translating controlled data from a study such as this to everyday use in the clinic, Wang says. The practical use of approaches such as molecular imagining with 99mTc-sestamibi single-photon emission CT/x-ray CT requires nuance from clinicians, and expert radiologists will always play an important role in tailoring the best care for patients, Wang concludes.