Adjustment of N stages of gastric cancer by the ratio between the metastatic and examined lymph nodes.
BACKGROUND
The present study attempted to determine whether N stage could be adjusted for the differences in survival rates based on the ratio between the examined and metastatic lymph nodes (LN ratio).


METHODS
Five hundred and twenty-nine patients with both >15 lymph nodes examined and >or= N1 after R0 resection were enrolled in the present study. To determine the cutoff LN ratio, the ratios at each N stage were compared at intervals of 10% with the log-rank test of Kaplan-Meier estimates of the survival curves.


RESULTS
The 5-year survival rate of patients with N1 was 71.7%. Those of N2 patients with LN ratio of <60% (n = 116) and >or=60% (n = 3) were 37.0% and 0%, respectively. Those of N3 patients with LN ratio of <30% (n = 32), between 30% and 60% (n = 67), and >or=60% (n = 26) were 31.0%, 16.3%, and 0%, respectively. Thus, adjusted N2 was obtained from the sum of N2 < 60% and N3 < 30%. N3 with an LN ratio between 30% and 60% was regarded as adjusted N3. N2 and N3 patients with an LN ratio of >or=60% were regarded as adjusted T4. The 5-year survival rate in patients with adjusted N2, N3, and N4 were 35.7%, 16.3%, and 0%, respectively. Multivariate analysis showed adjusted N stage and tumor depth were significant independent prognostic factors.


CONCLUSIONS
The results of this study suggest that, since stage migration can be induced in the N staging system, such stage migration can be adjusted by the LN ratio based on the survival rate.
Kim
Chan-Young
CY
Department of Surgery, Chonbuk National University Medical School, Chonju, Chonbuk, Korea.
Yang
Doo-Hyun
DH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis