Limited efficacy of preoperative computed tomographic scanning for the evaluation of lymph node metastasis in patients before radical prostatectomy

Abstract

To evaluate the efficacy of preoperative computed tomographic (CT) scanning in patients with presumed localized prostatectomy prior to radical retropubic prostatectomy. A retrospective study of 173 consecutive patients believed to be candidates for radical retropubic prostatectomy who underwent preoperative CT scanning regardless of preoperative prostate-specific antigen (PSA) value, clinical stage, or Gleason grade was undertaken. All patients underwent radical retropubic prostatectomy with bilateral pelvic lymph node dissection or aspiration needle biopsy of abnormal nodes on CT scanning. One hundred sixty-five of 173 patients (95.4%) were believed to have normal CT scans preoperatively. Of these 165 patients, 156 (94.5%) were found to have negative lymph nodes confirmed histologically at the time of lymphadenectomy. Nine patients (5.5%) were found to have lymph node metastases confirmed histologically, despite a negative CT scan. Computed tomographic scanning understaged 9 of 12 (75%) patients with proven metastases. Incidental abdominal pathology of clinical significance was documented in 4 patients (2.3%), including 2 with renal cell cancers, 1 with colon cancer, and 1 with a large (8 cm) abdominal aortic aneurysm. Prostate-specific antigen levels in patients with metastatic lymph nodes ranged from 0.7 to 130 ng/mL (Hybritech Tandem assay), with a mean level of 42 ng/mL. Although 9 of 33 patients (27.3%) with PSA levels greater than 25 ng/mL had node metastases, only 3 of these 33 patients (9.1%) were correctly diagnosed by CT scanning. Although additional numbers of patients with high PSA levels need to be evaluated, we could not find any justification for routine preoperative CT scanning in patients with a PSA of less than 25 ng/mL. These results suggest that significant savings can be realized by abandoning the practice of routine CT scanning for lymph node metastasis in all patients with newly diagnosed prostate cancer.