Location of Retroperitoneal Lymph Node Metastases in Upper Tract Urothelial Carcinoma: Results from a Prospective Lymph Node Mapping Study

Background: There is limited information on the distribution of retroperitoneal lymph node metastases (LNMs) in upper tract urothelial carcinoma (UTUC).Objective: To investigate the location of LNMs in UTUC of the renal pelvis or proximal ureter and short-term complications after radical nephroureterectomy (RNU) with lymph node dissection (LND). Design, setting, and participants: This was a prospective Nordic multicenter study (four university hospitals, two county hospitals). Patients with clinically suspected locally advanced UTUC (stage >T1) and/or clinical lymph node-positive (cN+) dis-ease were invited to participate. Participants underwent RNU and fractionated retroperitoneal LND using predefined side-specific templates. Outcome measurements and statistical analysis: The location of LNMs in the LND specimen and retroperitoneal lymph node recurrences during follow-up was recorded. Postoperative complications within 90 d of surgery were ascertained from patient charts. Descriptive statistics were used.Results and limitations: LNMs were present in the LND specimen in 23/100 patients, and nine of 100 patients experienced a retroperitoneal recurrence. Distribution per side revealed LNMs in the LND specimen in 11/38 (29%) patients with right-sided tumors, for whom the anatomically larger, right-sided template was used, in comparison to 12/62 (19%) patients with left-sided tumors, for whom a more limited template was used. High-grade complications (Clavien grade >= 3) within 90 d of surgery were registered for 13/100 patients. The study is limited in size and not powered to assess survival estimates.Conclusions: The suggested templates that we prospectively applied for right-sided and left-sided LND in patients with advanced UTUC included the majority of LNMs. High-grade complications directly related to the LND part of the surgery were limited.Patient summary: This study describes the location of lymph node metastases in patients with cancer in the upper urinary tract who underwent surgery to remove the affected kidney and ureter. The results show that most metastases occur within the template maps for lymph node surgery that we investigated, and that this surgery can be performed with few severe complications.