A protocol for performing extended lymph node dissection using primary tumor pathological features for patients treated with radical nephrectomy for clear cell renal cell carcinoma

Purpose: We determined the primary pathological features of clear cell renal cell carcinoma that are predictive of positive regional lymph nodes at radical nephrectomy (RN) and developed a protocol for the selective use of extended lymph node dissection. Materials and Methods: We studied 1,652 patients who underwent RN for unilateral pM0 sporadic clear cell renal cell carcinoma between 1970 and 2000. A multivariate logistic regression model was used to determine the pathological features of the primary tumor that were associated with positive regional lymph nodes at RN. Results: There were 887 (54%) patients with no positive nodes (pN0), 57 (3%) with 1 positive node (pN1), 11 (1%) with 2 or more positive nodes (pN2) and 697 (42%) who did not have any lymph nodes dissected (pNx). Nuclear grade 3 or 4 (p <0.001), presence of a sarcomatoid component (p <0.001), tumor size 10 cm or greater (p = 0.005), tumor stage pT3 or pT4 (p = 0.017) and histological tumor necrosis (p = 0.051) were significantly associated with positive regional lymph nodes in a multivariate setting. These features can be used to identify candidates for extended lymph node dissection at the time of RN. For example, only 6 (0.6%) of the 1,031 patients with 0 or 1 of these features had positive lymph nodes at RN compared with 62 (10%) of the 621 patients with at least 2 of these features. Conclusions: The primary tumor pathological features of nuclear grade, sarcomatoid component, tumor size, stage and presence of tumor necrosis can be used to predict patients at the greatest risk for regional lymph node involvement at RN.