The performance characteristics of CT scans have not been tested in contemporary patients treated with extended pelvic lymph node dissection (ePLND), he said. They studied 1,541 patients with clinically localized prostate cancer treated with radical prostatectomy (RP) and ePLND between 2002 and 2009 at their institution. ePLND was defined as including obturator, hypogastric and external iliac nodes. All patients underwent pre-operative CT scanning. Suspicious CT scans were defined by the presence of at least 1 pelvic enlarged node (>1 cm). The sensitivity, specificity and accuracy of CT scanning in detecting lymph node involvement (LNI) were calculated according to risk groups: low, intermediate, and high. Moreover, the performance characteristics of CT scans in detecting LNI was assessed according to most-informative cut-off risks for LNI calculated by using a nomogram developed on the same ePLND series.
Seventy-three patients (4.7%) had a CT scan suspicious for LNI and 24 of these (32.9%) had LNI at ePLND. Overall, 471 (30.6%), 689 (44.7%) and 381 (24.7%) patients had low, intermediate and high-risk prostate cancer, respectively. For the entire study cohort of 1,541 patients, CT sensitivity, specificity and accuracy was 13%, 96% and 54%, respectively. Similarly, sensitivity, specificity and accuracy were 8.3%, 96% and 52%, for 471 low-risk patients, respectively; 4%, 97% and 51%, for 689 intermediate-risk patients, respectively; and 18%, 94% and 56% for 381 high-risk patients, respectively. After applying the most-informative cut-offs derived from the nomogram (36% and 50% risk of LNI), the discriminative power of CT scanning for LNI detection remained modest with sensitivity, specificity and accuracy at 23.5%, 93% and 58.3% vs. 28.9%, 87.5% and 56.4% for patients with a calculated LNI risk>36 and >50%, respectively. He concluded that even in high-risk disease, optimal treatment planning shouldn’t be reliably based on the results of pre-operative CT scanning.
Presented by Alberto Briganti, et al. at the American Urological Association (AUA) Annual Meeting - May 14 - 19, 2011 - Walter E. Washington Convention Center, Washington, DC USA
Reported for UroToday by Christopher P. Evans, MD, FACS, Professor and Chairman, Department of Urology, University of California, Davis, School of Medicine.
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