Radio‐guided sentinel lymph node detection and lymph node mapping in invasive urinary bladder cancer: a prospective clinical study

Firas Aljabery, Ivan Shabo, Hans Olsson, Oliver Gimm, Staffan Jahnson

We investigated the possibility to detect sentinel nodes in patients with urinary bladder cancer (UBC) intra-operatively and whether the histopathological status of the identified sentinel nodes reflected that of the lymphatic field. We studied 103 patients with UBC pathological stage T1-T4 who were treated with cystectomy and pelvic lymph node (LN) dissection during 2005-2011 at the Department of Urology, Linköping University Hospital. Radioactive tracer Nanocoll 70 MBq (megabequerel) and blue dye were injected in the bladder wall around the primary tumour prior to surgery. Sentinel nodes were detected ex vivo during the operation with a hand-hold Geiger probe (Neoprobe Gamma Detection System). All lymph nodes were formalin-fixed, sectioned three times, mounted on slides and stained with hematoxylin-eosin. An experienced uropathologist (HO) evaluated the slides. The mean age of the patients was 69 years, and 80 (77%) were male. Pathological staging was T1-12 (12%), T2-20 (19%), T3-48 (47%) and T4-23 (22%). A mean number of 31 nodes per patient were examined (range 7-68), totaling 3,253 nodes. LN metastases were found in 41 (40%) patients. Sentinel nodes were detected in 80% (83 of 103) of the patients. Sensitivity and specificity for detecting metastatic disease by SNB varied between LN stations with an average value of 67% and 90%, respectively. Lymph node metastatic density had a significant prognostic impact; a value of 8% or more was significantly related to shorter survival. Lympho-vascular invasion occurred in 65% (n=67) of patients and was significantly associated with shorter cancer-specific survival (p<0.001). Sentinel node biopsy is not a reliable technique for per-operative localization of lymph node metastases during cystectomy for UBC. However, lymph-node metastatic density has a significant prognostic value in UBC and may be useful in the clinical context and in UBC oncologic and surgical research. Lympho-vascular invasion is a prognostic factor. This article is protected by copyright. All rights reserved.