Lymph node yield in pediatric, adolescent and young adult Renal Cell Carcinoma – How many are enough?

Purpose Pediatric, adolescent and young adult (PAYA) patients with renal cell carcinoma (RCC) have a high rate of LN involvement, yet data to guide surgical lymph node (LN) management in this group is limited. The objective is to describe a LN yield threshold to quantify the chance of missing occult LN involvement at ≤ 10% in PAYAs with RCC. Materials & methods The National Cancer Database was queried for patients aged ≤ 30 y with unilateral, non-metastaticRCC from 2004 to 2013. The probability of a false negative LN sampling was determined on the cohort of patients who had at least one positive LNand ≥ 2 LNs examined. For a given LN yield, the probability that a positive LN exists but none were found was estimated using a beta-binomial model. Results We identified 112 patients meeting study criteria. Median age was 24 y and median tumor size was 9.5 cm (IQR 5.8–14). The median number of LNs sampled was 7 (IQR 4–12) and the median number of LNs positive was 4 (IQR 2–7). To achieve ≤ 10% probability of a false-negativeLN sampling, the beta-binomial model estimated that 5 LNs (95% CI4–7) must be sampled. Conclusions The desired LN yield to reduce the risk of a false-negativeLN sampling in PAYAs with RCC to ≤ 10% is 5. This is in keeping with prior studies identifying a LN yield of 6–10 to achieve the same. These data may be used to standardize surgical guidelines when treating PAYAs with renal tumors. Level of Evidence II.