Correlations found between CT features, underlying mutations of renal cell carcinoma

A radiogenomics analysis of clear cell renal cell carcinoma (RCC) demonstrated associations between CT features and underlying mutations that require further investigation and validation, according to a study published in the February issue of Radiology.

While CT serves as the primary modality for clinical decision-making in the staging and treatment of RCC, the standard of reference is evolving to the genomic level. Several genetic mutations of RCC—VHL, PBRM1, BAP1, SETD2, and KDM5C—have also been recently identified. Lead author Christoph A. Karlo, MD, of the Memorial Sloan-Kettering Cancer Center in New York City, and colleagues conducted a retrospective study that included 233 patients with RCC to determine the associations between its CT features and genetic mutations.

Once three radiologists independently reviewed pretreatment CT images of all carcinomas, associations between the features and mutations were tested with the Fisher exact test. VHL was frequent in 53.2 percent of the clear cell RCCs, PBRM1 was in 28.8 percent, SETD2 in 7.3 percent, KDM5C was in 6.9 percent of the carcinomas, and BAP1was in 6 percent.

VHL mutations were significantly associated with well-defined tumor margins, nodular tumor enhancement, and gross appearance of intratumoral vascularity. Mutations of KDM5C and BAP1 were significantly associated with evidence of renal vein invasion. VHL mutations were significantly more common among solid clear cell RCC than multicystic clear cell RCC.

“This preliminary radiogenomics analysis of clear cell RCC revealed associations between CT features and underlying mutations that therefore warrant further investigation and validation,” wrote the study’s authors. “Moreover, future studies are necessary to combine individual CT features into CT imaging phenotypes of clear cell RCC and correlate them to underlying genomic profiles rather than individual gene mutations.”