Dynamic sentinel node biopsy in penile cancer: initial experiences at a Swedish referral centre

Abstract

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? According to the current European Association of Urology Guidelines, dynamic sentinel node biopsy is the recommended approach to assess lymph node status in men with cN0 intermediate and high risk penile cancer. Nevertheless, most encouraging results derive from a limited number of studies. The present study shows a false-negative rate of 15%, comparable with or better than several previous studies. Nevertheless, the aim should be a false-negative rate of no more than 5%. We conclude that increased overall experience and the use of the complete modern dynamic sentinel node biopsy protocol are paramount to improve results. • To evaluate the false-negative rate and complication rate of dynamic sentinel node biopsy (DSNB) in penile cancer. • In this retrospective study, 58 unilaterally or bilaterally clinically lymph node negative (cN0) patients with penile cancer (57 squamous cell carcinomas and one malignant melanoma), scheduled for DSNB at the Örebro University Hospital, Sweden, between 1999 and 2011, were analysed. • Preoperative ultrasonography and fine-needle aspiration cytology of suspicious nodes were not introduced until 2008. • Patients were assessed by lymphoscintigraphy using (99m) technetium nanocolloid on the day before surgery and the dissection of sentinel nodes was aided by the lymphoscintigraphic images and intraoperative detection of radiotracer and patent blue dye. • The false-negative rate and complication rate were calculated per groin. • Of the 58 patients, 32 (55%) underwent preoperative ultrasonography. • Two patients had positive fine-needle aspiration cytology and discontinued further DSNB protocol. Of the remaining 56 patients, all but one were bilaterally cN0 and hence 111 cN0 groins were assessed by lymphoscintigraphy. • In the 55 bilaterally cN0 patients, lymphoscintigraphy visualized a bilateral sentinel node in 34 (62%). • At surgery, all excised sentinel nodes were radioactive while 43% were additionally blue. In total, at least one sentinel node was harvested in 96 (86%) of the DSNB staged groins. • A positive sentinel node was found in 11 groins (bilaterally in three patients). During a median follow-up of 21 months, two false-negative cases emerged, producing a false-negative rate of 15%. Both false-negative cases occurred during the first half of the study. The complication rate was 10%. The majority of complications were minor and transient. • DSNB is a minimally invasive staging tool in men with cN0 penile cancer, enabling early detection of metastatic disease and thus optimal care. • Our false-negative rate of 15% is comparable or even favourable in comparison with several previous studies, but far from the 5% or less that we aim for. The complication rate found is somewhat higher than previously reported. • With increased overall experience and the continued use of the complete DSNB protocol, we believe our results will improve and the complication rate will decrease.