Lymph node size does not correlate with the presence of prostate cancer metastasis

Objectives. To determine whether lymph node size is a surrogate marker for lymph node metastasis. Methods. We reviewed 980 patients who underwent radical retropubic prostate ctomy with bilateral pelvic lymph node dissection for clinically localized prostate cancer, of whom 63 had lymph node metastases. A comparable group o f patients with prostate cancer undergoing radical prostatectomy who did no t have lymph node involvement was identified using the following parameters : serum prostate-specific antigen level, clinical and pathologic stage, and pre- and postoperative Gleason score. The axial and longitudinal dimension s of the nodes from patients with and without metastases were analyzed to a ssess the significance of lymph node size in predicting the presence of met astases. Ail patients had negative preoperative computed tomography (CT) an d bone scans. Of the 63 patients with lymph node metastases, 48 had tissue available for measuring the dimensions of the lymph nodes. Results. A total of 76 metastatic and 92 negative lymph nodes were identifi ed from the patients with and without metastatic nodes, respectively. The m ean nodal longitudinal size was 1.65 cm (range 0.2 to 6.5) and 3.50 cm (ran ge 0.5 to 9) for positive and negative nodes, respectively (P = 0.0001). Th e mean axial nodal size was 0.8 cm (range 0.2 to 3.2) and 1.0 cm (range 0.2 to 2.2) for positive and negative lymph nodes, respectively. In 56 metasta tic nodes (74%), the axial size was less than 1 cm and in 20 (26%) less tha n 5 mm. Conclusions. Lymph node size should not be used as a surrogate for the pres ence of lymph node metastases. Although no patient had enlarged lymph nodes by CT scan criteria (greater than 1.5 cm), 6 (8%) of 48 and 19 (12%) of 48 patients with and without lymph node metastases, respectively, had nodes w ith an axial dimension greater than 1.5 cm. (C) 1999, Elsevier Science Inc. All rights reserved.