Laparoscopic extended pelvic lymph node ( LN) dissection as validation of the performance of [11C]-acetate positron emission tomography/computer tomography in the detection of LN metastasis in intermediate- and high-risk prostate cancer.

Objectives To evaluate the accuracy of the radiopharmaceutical [¹¹C]-acetate combined with positron emission tomography/computer tomography (acetate- PET/ CT) in lymph node ( LN) staging in newly diagnosed prostate cancer cases. A second aim was to evaluate the potential discriminative properties of acetate- PET/ CT in clinical routine. Patients and Methods In a prospective comparative study, from July 2010 to June 2013, 53 men with newly histologically diagnosed intermediate- or high-risk prostate cancer underwent acetate- PET/ CT investigation at one regional centre before laparoscopic extended pelvic LN dissection ( ePLND) at one referral centre. The sensitivity, specificity and accuracy of acetate- PET/ CT were calculated. Comparisons were made between true-positive and false-negative PET/ CT cases to identify differences in the clinical parameters: PSA level, Gleason status, lymph metastasis burden and size, calculated risk of LN involvement, and curative treatment decisions. Results In all, 26 patients had surgically/histologically confirmed LN metastasis ( LN+). Acetate- PET/ CT was true positive in 10 patients, false positive in one, false negative in 16, and true negative in 26. The individual sensitivity was 38%, specificity 96%, and accuracy 68%. The acetate- PET/ CT positive cases had significantly more involved LNs (mean 7.9 vs 2.4, P < 0.001) with larger cancer diameters (14.1 vs 4.9 mm, P = 0.001) and fewer eventually had treatment with curative intent (40% vs 94%, P <0.005), although we lack long-term outcome data. Conclusion Acetate- PET/ CT has too low a sensitivity for routine LN staging but the specificity is high. The acetate- PET/ CT positive cases have a very high burden of LN spread. [ABSTRACT FROM AUTHOR]