Patterns of Lymphatic Metastases in Upper Tract Urothelial Carcinoma and Proposed Dissection Templates

Purpose: Information on patterns of lymph node metastases for upper tract urothelial carcinoma is sparse. We investigated patterns of lymph node metastases in upper tract urothelial carcinoma. Materials and Methods: We performed a retrospective multi-institutional study of 73 patients with N+M0 upper tract urothelial carcinoma who underwent template lymphadenectomy during nephroureterectomy. Anatomical locations of tumor, and number of lymph nodes removed and positive lymph nodes were analyzed and descriptive statistics were performed. Results: On the right side the 20 renal pelvis tumors had lymph node metastases to the hilum in 22.1% of cases, and to paracaval, retrocaval and interaortocaval regions in 44.1%, 10.3% and 20.6%, respectively. The 10 proximal ureter tumors had lymph node metastases to the hilum in 46.2% of cases, and to paracaval and retrocaval regions in 46.2% and 7.7%, respectively. The 2 distal ureter tumors had lymph node metastases equally to the paracaval and pelvic regions. On the left side the 24 renal pelvis tumors had lymph node metastases to the hilum region in 50.0% of cases and to the para-aortic region in 30.0%. The 8 proximal ureter tumors had lymph node metastases to the hilum region in 36.4% of cases and the para-aortic region in 63.6%. The 5 mid ureter tumors had lymph node metastases to the para-aortic, common iliac and internal iliac regions in 40%, 40% and 20% of cases, respectively. The 4 distal ureter tumors had lymph node metastases to the para-aortic, common iliac, external iliac and internal iliac regions in 33.3%, 33.3%, 16.7% and 16.7% of cases, respectively. Interaortocaval involvement from both sides as well as out of field lymph node metastases appeared to occur secondarily. Consolidated templates were constructed based on the available data. Conclusions: Upper tract urothelial carcinoma has characteristic patterns of lymph node metastases depending on the side and anatomical location of the primary tumor, including right-to-left migration and involvement of interaortocaval nodes in the setting of proximal disease. Standardized dissection templates should be prospectively evaluated in multicenter trials to assess morbidity and potential clinical benefit.