T2 weighted-based radiomics proved superior in classification performance than qualitative assessment and diffusion-weighted (DW) imaging for diagnosing pathologic complete response (pCR) in patients with rectal cancer who received therapy prior to their main treatment, according to a March 8 study in Radiology.

“Currently, no consensus exists in the literature on which approach is the most reliable to assess tumor response after neoadjuvant [chemotherapy-radiation therapy] CRT, and a nonsurgical strategy is not currently supported by the National Comprehensive Cancer Network guidelines,” wrote corresponding author Iva Petkovska, MD, with the Clinical Center of Serbia, and colleagues. “Therefore, there is an increasing need for evaluation of tumor response by using a variety of techniques.”

The team, which included representatives from the Memorial Sloan Cancer Center in New York, retrospectively analyzed MR images of 114 patients with rectal cancer who had received CRT.

A total of 21 (18 percent) of patients achieved pCR. The radiomic classifier achieved a 95 percent confidence interval, 100 percent sensitivity, 91 percent specificity, positive predictive value of 72 percent and negative predictive value of 72 percent.

Authors also pointed out “the diagnostic performance of radiomics was significantly higher than was qualitative assessment at T2-weighted imaging or DW imaging alone,” wrote Petkovska et al.

Radiomics produced a higher specificity and positive predictive value than the combined T2-weighted and DW imaging approach.

“The radiomics measures by using cross-validation showed better classification performance compared with the qualitative assessment for diagnosing pCR in patients with locally advanced rectal cancer after neoadjuvant therapy,” wrote Petkovska et al.

However, researchers noted the results need validation on a larger, independent data set to determine if the method is suitable for clinical implementation.

“After validation, this radiomic assessment may become a potential imaging biomarker of [clinical complete response] cCR and complement the current modalities in the management of rectal cancer after neoadjuvant treatment,” according to Petkovska et al.