NEW YORK (Reuters Health) – Whole-body (WB) scans using either magnetic resonance imaging (MRI) or positron-emission tomography (PET) with CT, both have high sensitivity and specificity in detecting distant malignancies in patients with cancer, a team from Nanning, China has shown.

Furthermore, “The combined use may provide more added value than WB-PET/CT and WB-MRI alone,” the authors report in the Annals of Oncology online September 12.

Dr. C.Y. Li, at The First Affiliated Hospital of Guangxi Medical University, and colleagues explain that several studies have compared whole-body PET/CT with MRI for detecting distant malignancies – whether metastases or second primary tumors — in cancer patients.  However, the results have been controversial.

They therefore undertook a meta-analysis of 13 relevant prospective studies that included a total of 1239 patients.  Eight articles provided patient-level data, four articles reported lesion-level results, and one article included both patient-level and lesion-level information.

The pooled data showed that on a per-patient basis, the sensitivity and specificity of whole-body PET/CT were 85% and 96% respectively, while corresponding figures for MRI were 86% and 97%.

At the lesion level, sensitivity and specificity were 85% and 90% with PET/CT compared with 88% and 89% with MRI, the team found.

Four studies had data on the combined use of PET/CT and MRI.  With this approach, patient-level sensitivity and specificity were 89% and 98%, respectively, the report indicates.  In these studies, the single-modality sensitivity and specificity numbers were 82% and 97% with PET/CT and 81% and 98% with MRI.

Whole-body scans with PET/CT or MRI have different advantages at various sites, the author point out.  For example, PET/CT performs better than MRI in detecting distant nodes, whereas MRI is better than PET/CT in identifying brain or bone metastases.

“Thus, the combined use of WB-PET/CT and WB-MRI may correct more diagnostic errors and enhance the diagnostic accuracy of WB-PET/CT and WB-MRI alone,” Dr. Li and colleagues conclude.

SOURCE: http://dx.doi.org/10.1093/annonc/mds234

Ann Oncol 2012