Potential added value of whole-body DWI-MRI in the diagnostic workup of patients with adenocarcinoma of unknown primary (ACUP): a prospective pilot study
Author Block: J. Willemse, M. Lahaye, P. Snaebjornsson, S. Marchetti, M. Vollebergh, L. van Golen, W. Vogel, R. G. H. Beets-Tan, D. M. J. Lambregts; Amsterdam/NL
Purpose: The purpose of this prospective diagnostic pilot study was to investigate the potential added benefit of whole-body (chest-abdomen) MRI including DWI (further referred to as WB-MRI) in this diagnostic work-up of patients with adenocarcinoma of unknown primary (ACUP).
Methods or Background: From January 2022 to August 2023, the option of WB-MRI was added as an adjunct diagnostic tool to the routine clinical workup, including CT, FDG-PET/CT, lab tests, and biopsies for ACUP patients in our institution. The choice of whether to perform an MRI was discussed by a multidisciplinary team and guided by all available clinical information (e.g. if the primary tumour could likely be suspected to be located within the abdomen/pelvis). We analysed the impact of WB-MRI in terms of primary tumour identification and detection of additional metastatic sites.
Results or Findings: WB-MRI was performed in 27 ACUP patients. In 6/27 (22%) of patients, WB-MRI suggested a possible primary tumour location undiagnosed on previous CT and/or FDG-PET/CT, including 2 bile duct cancers, 1 ovarian, 1 appendiceal, 1 duodenal and 1 pancreatic cancer. In 5 of these 6 cases, the WB-MRI diagnosis aligned with and supported the final diagnosis, established by integration of clinicopathological data with whole genome sequencing. In addition, WB-MRI discovered extra metastatic sites in 6/27 (22%) of patients, including peritoneal metastases (n=3), bone (n=1), kidney (n=1) and testicular metastases (n=1).
Conclusion: This study demonstrates the potential added value of WB-MRI in the search for the underlying primary tumour in the complex diagnostic work-up of patients with disseminated adenocarcinoma of unknown primary.
Limitations: This was a small pilot study with a correspondingly small cohort.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: This was a retrospective analysis of data acquired prospectively as part of routine clinical care, approved by the local Institutional Research Board.