Introduction

Information on distribution of regional lymph node metastasis (LNM) in upper urinary tract urothelial cancer (UTUC) are sparse, and the appropriate extent of lymph node dissection (LND) remains unclear. The objective of the present study was to investigate the distribution of LNM in a large multicenter case series of the Urologic Oncology Group of the Japan Clinical Oncology Group (JCOG).

Methods

The multicenter study, JCOG1110A, included 2,744 patients with non-metastatic UTUC who underwent radical nepheroureterectomy in 30 institutions in Japan between 1995 and 2009. In this analysis, patients with previous or simultaneous bladder cancer, patients who received neoadjuvant treatment, and patients without data of primary tumor site were excluded. The indication and extent of LND were determined by each surgeon or institution. Anatomical locations of primary tumor and number of patinets with positive lymph nodes (LNs) in each LN region were analyzed and descriptive statistics were performed.

Results

Of 1932 patients, we identified 188 (9.7%) pathologically node positive patients. On the right and left side, primary tumor location was documented as 51 and 76 patients with renal pelvis, 2 and 5 with upper ureter, 7 and 9 with middle ureter, 20 and 18 with lower ureter. The distribution of LNM in upper ureteral cancer was similar to that in renal pelvic caner, and the distribution in middle ureteral cancer was similar to that in lower ureteral cancer. Wherein we classified UTUC into two groups, upper UTUC (renal pelvis to upper ureter) and lower UTUC (middle to lower ureter). On right side, upper UTUC of 53 patients had LNM to renal hilar, paracaval and interaortocaval regions in 59%, 23% and 13%. Lower UTUC of 27 patients had LNM to common iliac, obturator, external and internal iliac regions in 22%, 33%, 19% and 11%, and also to renal hilar and interaortocaval region in 7% and 7%. On left side, upper UTUC of 81 patients had LNM to the renal hilar, paraaortic, interaortocaval regions in 54%, 37% and 5%. Lower UTUC of 27 patients had LNM to the common iliac, obturator, external and internal iliac regions in 19%, 26%, 11% and 7%, and also to renal hilar and paraaortic region in 11% and 26%.

Conclusions

UTUC has characteristic distribution of regional LNM depending on the side and location of primary cancer. LNM of lower UTUC was detected not only in pelvic region but also in upper abdominal region. These results support to establish the standardized dissection extent, which is necessary for evaluating potential clinical benefit of LND.

Funding

This study was supported in part by the National Cancer Center Research and Development Fund (23-A-20, 26-A-4).