An evaluation of the number of lymph nodes examined and survival for node-negative esophageal carcinoma: data from China.
BACKGROUND
The current American Joint Committee on Cancer (AJCC) staging system for esophageal cancer does not define the minimum number of lymph nodes (LNs) necessary for accurate nodal staging. This study aimed to seek the minimum number of LNs examined for adequate nodal staging of patients with node-negative esophageal cancer.


METHODS
We conducted a retrospective review of 592 patients undergoing R0 resection with node-negative esophageal carcinoma between December 1996 and December 2004. The relationship between the total number of examined LNs and death from esophageal cancer was investigated by means of a scatterplot of this variable versus Martingale residuals from a Cox proportional hazard regression model without the variable of interest. A smoothed line fit of the scatterplot was applied to detect the reasonable cutoff point.


RESULTS
The patients were classified into four categories according to the number of examined LNs: < or =5, 6 to 9, 10 to 17, and > or =18. A reduced hazard ratio of death was observed with an increasing number of LNs examined. The 5-year cancer-specific survival rate was 42.8% among patients with < or =5 LNs examined, compared with 52.6, 56.8, and 75% for those with 6-9 LNs, 10-17 LNs, and > or =18 LNs, respectively. Multivariate Cox regression analysis suggested that female sex, lower grade of cell differentiation, lower T category and increasing number of examined LNs were independent factors favoring cancer-specific survival.


CONCLUSIONS
At least 18 LNs should be resected for accurate staging of operable esophageal carcinoma. However, a validation from other institute is warranted.
Yang
Hao-Xian
HX
Department of Thoracic Surgery, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
Xu
Ying
Y
Fu
Jian-Hua
JH
Wang
Jun-Ye
JY
Lin
Peng
P
Rong
Tie-Hua
TH
D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000473:pathology; D002681:China; D004938:Esophageal Neoplasms / Q000401:mortality* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D015996:Survival Rate