Lymph Node Yield Associated With Survival in Upper Urinary Tract Carcinoma

February 11, 2017

Though it is used infrequently, lymph node dissection with higher yield of lymph nodes is associated with lower all-cause mortality among patients with urothelial carcinoma of the upper urinary tract who undergo nephroureterectomy.

Though it is used infrequently, lymph node dissection (LND) with higher yield of lymph nodes is associated with lower all-cause mortality among patients with upper urinary tract urothelial carcinoma (UTUC) who undergo nephroureterectomy, according to a new study.

UTUC is relatively rare, but is a highly aggressive malignancy. “UTUC has a propensity for early metastatic spread to the regional lymph nodes (LNs), with LN metastases being found at the time of radical nephroureterectomy in approximately 20% to 25% of patients with T2 tumors,” and more in T3 or T4 tumors, wrote study authors led by Piotr Zareba, MD, MPH, of Memorial Sloan Kettering Cancer Center in New York.

The use of LND in these patients has not been standardized however, perhaps because of a lack of established association with survival. The new study used the National Cancer Data Base to examine associations between LN yield and survival.

In total, the study included 14,472 patients with non-metastatic UTUC who underwent nephroureterectomy between 2004 and 2012. Of those, 2,926 patients (20%) underwent LND, and the median yield was two LNs. The results of the analysis were published online ahead of print in Cancer.

Among the patients who underwent LND, a higher LN yield was associated with better overall survival; there was a 6% decrease in overall survival hazard for every five LNs removed, meaning the multivariable hazard ratio (HR) was 0.94 (95% CI, 0.89–1.00; P = .034). An analysis showed that the relationship between yield and survival was non-linear; the lowest hazard occurred at a yield of approximately 15 LNs.

This was more pronounced among lymph node–negative patients, with an HR of 0.86 per five LNs (95% CI, 0.79–0.94; P = .001), and was not seen in lymph node–positive patients, with an HR of 1.01 per five LNs (95% CI, 0.94–1.08; P = .89).

“The low median LN yield and high rate of positivity in the LNs sampled suggests that the attitude toward LND during nephroureterectomy at the majority of centers is that of a staging procedure, with selective removal of suspicious LNs (‘node plucking’) being performed without interest in extending the dissection template in the setting of positive,” the authors wrote, noting that this study was limited by its observational nature.

They added that the question of therapeutic benefit from extended LND remains complex, and prospective study is still needed to more firmly establish best practices. “The findings of the current study suggest that this question is important to address given the high degree of variability in existing practice and the potential for significant patient benefit,” they concluded.