Incidental Findings at Initial Imaging Workup of Patients With Prostate Cancer: Clinical Significance and Outcomes

OBJECTIVE. The purpose of this article is to evaluate the frequency and clinical relevance of incidental findings in patients with prostate cancer who underwent abdominopelvic contrast-enhanced CT examination for initial staging workup. MATERIALS AND METHODS. We retrospectively reviewed 355 initial staging abdominopelvic contrast-enhanced CT examinations conducted from January 2000 to December 2010 in patients with prostate cancer for incidental findings that were not related to prostate cancer. A finding was judged to be potentially significant if therapeutic intervention, additional imaging, or tissue sampling was deemed advisable. The rate of incidental findings was correlated to patients' age and stratified prostate cancer risk groups. RESULTS. We found 779 incidental finding in 292 patients (82.3%), of which 75 findings in 73 patients (20.6%) were potentially significant. Indeterminate masses were the most prevalent significant finding (n = 62). Synchronous malignancy was detected in 21 patients (5.9%). Kidney cancer (n = 7 [1.97%]) was the most common malignancy, followed by lymphoma (n = 4 [1.13%]). Staging of the cancers revealed that 15 patients, including all of those with renal cancer, had N0M0 disease. Significant vascular abnormalities were reported in six cases. Additionally, significant findings, synchronous malignancies in particular, were identified at a higher rate in patients older than 65 years. However, no significant differences were noticed between the different prostate cancer risk groups. CONCLUSION. Abdominal contrast-enhanced CT for initial staging of prostate cancer shows a considerable prevalence of incidental vascular events and synchronous cancers, with kidney cancers being the most common. Notably, 71.5% of these malignancies were at early stage. Our results show an incremental value of CT in prostate cancer staging, with an emphasis on focused evaluation of the kidneys.