Does the mechanism of lymph node invasion affect survival in patients with pancreatic ductal adenocarcinoma?
BACKGROUND
Lymph node metastases are prognostically significant in pancreatic ductal adenocarcinoma. Little is known about the significance of direct lymph node invasion.


OBJECTIVE
The aim of this study is to find out whether direct lymph node invasion has the same prognostic significance as regional nodal metastases.


METHODS
Retrospective review of patients resected between 1/1/1993 and 7/31/2008. "Direct" was defined as tumor extension into adjacent nodes, and "regional" was defined as metastases to peripancreatic nodes.


RESULTS
Overall, 517 patients underwent pancreatic resection for adenocarcinoma, of whom 89 had one positive node (direct 26, regional 63), and 79 had two positive nodes (direct 6, regional 68, both 5). Overall, survival of node-negative patients was improved compared to patients with positive nodes (N0 30.8 months vs. N1 16.4 months; p < 0.001). There was no survival difference for patients with direct vs. regional lymph node invasion (p = 0.67). Patients with one positive node had a better overall survival compared to patients with >/=2 positive nodes (22.3 and 15 months, respectively; p < 0.001). The lymph node ratio (+LN/total LN) was prognostically significant after Cox regression (p < 0.001).


CONCLUSIONS
Isolated direct invasion occurs in 20% of patients with one to two positive nodes. Node involvement by metastasis or by direct invasion are equally significant predictors of reduced survival. Both the number of positive nodes and the lymph node ratio are significant prognostic factors.
Konstantinidis
Ioannis T
IT
Department of Surgery, Massachusetts General Hospital, Boston, MA, USA.
Deshpande
Vikram
V
Zheng
Hui
H
Wargo
Jennifer A
JA
Fernandez-del Castillo
Carlos
C
Thayer
Sarah P
SP
Androutsopoulos
Vasiliki
V
Lauwers
Gregory Y
GY
Warshaw
Andrew L
AL
Ferrone
Cristina R
CR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D021441:Carcinoma, Pancreatic Ductal / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis