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

Background

Muscle invasive urinary bladder cancer (UBC) is associated with pathologic lymph node (LN). Lymphadenectomy is a routine surgical method to treat UBC, but it cause great surgical trauma and morbidity. Sentinel node biopsy technique (SNB) is a successful surgical procedure used in evaluating LN metastasis in treatment of several tumor types. In this study, we investigated systematically the reliability of SNB for detection of pathological LN during cystectomy, the significance of tumor localization in the bladder to predict the site of LN metastasis, as well as the prognostic significance of LN metastasis density (LNMD) on survival.

Methods

The study included 103 patients with UBC, stages T1-T4, who were treated with cystectomy and pelvic lymph node dissection during 2005-2011 at the Department of Urology, Linköping University Hospital. Intravesical injections of the radioactive tracer Nanocoll 70 MBq and blue dye were injected in the bladder wall around the primary tumor prior to surgery. SNB was detected ex vivo during the operation with a hand-hold Geiger probe (Neoprobe Gamma Detection System). All LNs were formalin-fixed, sectioned three times and stained with haematoxylin-eosin. All slides were evaluated by an experienced uro-pathologist.

Results

The mean age of the patients was 69 years and 80 (77%) patients were male. Pathological staging was T1 N = 12 (12%), T2 N = 20 (19 %), T3 N = 48 (47%) and T4 N = 23 (22%). There were 3253 nodes examined, mean 31 LN/patient, range 7-68. LN metastases occurred in 41 (40 %) patients. Sentinel nodes were detected in 83 (80%) patients. The sensitivity and specificity of detecting metastatic disease by SNB varied between pelvic LN stations with an average value of 67% and 90% respectively. LNMD ≥8% were significantly related to shorter survival (p 

Conclusions

SNB is not a reliable technique for per-operative localization of LN metastases during cystectomy for UBC. LNMD and LVI have a significant prognostic value in UBC and may be a useful variables in the clinical context and in UBC research. Tumor localization in the bladder predicts location of positive LN in pelvis.

Clinical trial identification

Legal entity responsible for the study

Department of urology, University Hospital in Linköping, Sweden.

Funding

FoU and ALF research grants from the County Council of Östergötland, Linköping, Sweden.

Disclosure

All authors have declared no conflicts of interest.