Amino acid PET can accurately distinguish treatment-related changes in recurrent or progressive brain metastases, according to a newly published meta-analysis. A specificity of 84% indicated that it could reduce the number of invasive procedures and overtreatment in patients who actually experienced treatment-related changes. The study was published in the May issue of the Journal of Nuclear Medicine.
Brain metastases occur in 20% to 40% of all cancer patients, most likely in patients with lung, breast, and kidney cancers, melanoma, and gastrointestinal cancers. Treatment for people with brain metastases usually includes surgery, radiation therapy, and chemotherapy. Some patients developed treatment-related changes such as radiation necrosis or pseudoprogression.
"Distinguishing recurrent or progressive brain metastases from treatment-related changes is challenging," said Igor Yakushev, senior physician at the Department of Nuclear Medicine at the Technical University of Munich, Germany. "Because the management of patients with recurrent or progressive brain metastases and treatment-related changes is quite variable, an accurate and early differential diagnosis is critical."
The meta-analysis included 12 amino acid PET radiotracer studies. These studies included a total of 397 patients and 547 lesions. Overall, 269 lesions (49%) were found to be recurrent or progressive brain metastases. Using histological examination and/or radiological and clinical follow-up as references, the pooled sensitivity and specificity of amino acid PET were found to be 82% and 84%, respectively.
"This study provides level IIa evidence on the diagnostic utility of amino acid PET in the differential diagnosis of recurrent or progressive brain metastases," Yakushev said. "These findings are consistent with the growing role of molecular imaging in the management of patients with brain tumors, but the results also point to the potential for further improvements in diagnostic accuracy."