Incidence and location of lymph node metastases in patients undergoing radical cystectomy for clinical non-muscle invasive bladder cancer: Results from a prospective lymph node mapping study

ObjectivesThe objective of this study is to investigate the incidence and location of lymph node metastases (LNMs) in patients undergoing radical cystectomy (RC) and lymph node dissection (LND) for clinical non-muscle invasive bladder cancer (NMIBC).Methods and materialsProspectively collected data of 637 patients who underwent RC and 'superextended' LND with intent-to-cure for urothelial carcinoma of the bladder between 2002 and 2008 were examined. Inclusion criteria were (a) clinical stage Ta, Tis-only, or T1, (b) muscle presence at diagnostic transurethral resection in clinical T1 patients, (c) no prior diagnosis of≥T2 disease, (d) no neoadjuvant therapy, and (e) lymphatic tissue sample submitted from all 13 predesignated locations. Lymph node mapping was performed in all patients to determine the location of metastatic lymph nodes. Median follow-up time was 4.7 years. Recurrence-free survival and overall survival were reported.ResultsA total of 114 patients were included of whom 9 patients (7.9%) had LNM. Stratified by clinical stage, LNM was present in 6/67 (9.0%) patients with cT1, 3/25 (12.0%) patients with cTis-only, and none of the 22 patients with cTa. Of the 9 node-positive patients (33.3%), 3 had LNM proximal to the aortic bifurcation. No skip metastases were found. After RC, 27 patients (23.7%) were upstaged to muscle invasive disease; of whom 16.7% had cT1, 2.6% had cTa, and 4.4% had cTis-only. Of the remaining 87 patients with pathologic NMIBC, 1 patient (1.1%) had LNM, limited to the true pelvis. Five-year RFS was 82.3%, 81.5%, and 62.0% in patients with pathologic NMIBC, clinical NMIBC, and pathologic muscle invasive bladder cancer, respectively.ConclusionsRoutine LND is important in patients with cT1 and cTis-only bladder cancer, but may have limited value in patients with cTa. LNM beyond the boundaries of a standard LND occurred in up to one-third of node-positive patients. In the absence of skip metastases, however, performing a standard LND would correctly identify all node-positive patients. Whether removal of LNM proximal to the common iliac vessels provides a survival benefit remains to be evaluated in future prospective studies.