The evaluation of metastatic lymph node ratio staging system in gastric cancer.

BACKGROUND

To evaluate the prognostic value and staging accuracy of the metastatic lymph node ratio (rN) staging system for gastric cancer.

METHODS

A total of 1,075 patients with gastric cancer who underwent curative surgery between 2000 and 2009 at our institute were analyzed. Lymph node status was assigned according to the American Joint Committee on Cancer (AJCC) pN system and rN system. Patients with >15 (group 1, n = 691) and ≤15 lymph nodes (group 2, n = 384) retrieved were analyzed separately.

RESULTS

The rN staging system was generated using 0.2 and 0.5 as the cutoff values of lymph node ratio and then compared with AJCC pN stages. A linear regression model revealed that the number of retrieved lymph nodes was related to the number of metastatic lymph nodes, but not with rN. After a median follow-up of 47.66 months, the 5-year survival rates of N0, N1, N2, and N3 patients of group 1 were significantly better than group 2, whereas the differences were not obvious in the rN classification.

CONCLUSIONS

The rN category is a better prognostic tool than the AJCC pN category for gastric cancer patients after curative surgery regardless of the number of lymph node examined.