Purpose: In rectal cancer variation in lymph node recovery influences the detection of nodal metastases and prognosis among Dukes B (Stage II) cases. However, the possible prognostic importance of node size and inherent patient/tumor characteristics in determining node recovery has not been studied.
Methods: We examined 269 Dukes B (Stage II) rectal tumors, with a mean of 12 nodes per case. Primary tumor characteristics were correlated with the number and size of recovered nodes. Clinical follow-up permitted determination of long-term survival.
Results: The five-year survival of 94 Dukes B cases with nine or fewer nodes was 69.4 percent vs. 87.6 percent in 175 cases with ten or more nodes (P = 0.001). Lymph nodes were smaller in patients dying of recurrence; among 130 Dukes B patients whose mean node diameter was <4 mm, survival was 73.3 vs. 88 percent when mean nodal diameter was > or =4 mm. The number and size of recovered nodes was related to patient age, histologic antitumor immune response, and tumor growth pattern. By combining the number and size of nodes, a poor prognosis subgroup of 98 Dukes B patients with relatively few large nodes (no more than 5 measuring > or =4 mm) was identified with a five-year survival of 65.6 percent compared with 89.6 percent for the remaining 158 Dukes B cases (P < 0.0001).
Conclusions: In Dukes B rectal tumors, the number and size of lymph nodes are related to inherent patient and tumor characteristics and permit the identification of Dukes B cases at increased risk of recurrence. A valid comparison of nodal sampling efficiency between centers necessitates measuring and counting harvested lymph nodes.