How does the number of resected lymph nodes influence TNM staging and prognosis for esophageal carcinoma?

BACKGROUND

It is proposed by International Union Against Cancer (UICC) and American Joint Committee on Cancer (AJCC) that at least 6 lymph nodes (LN) should be removed during resection of esophageal cancer for an accurate N classification. However, large series evidence is needed. The aim of this study is to assess the impact of total number of removed LNs during esophagectomy on UICC-TNM staging and long-term survival.

MATERIALS AND METHODS

The clinicopathological data and follow-up results of 1098 patients with advanced esophageal carcinoma who underwent an esophagectomy were analyzed.

RESULTS

The survival experience of group A (removed LNs <6) was worse than that of group B (removed LNs > or = 6). With the stratification analysis according to N and TNM stage, for patients with pN0 cancers, the survival in group A was worse than that in group B (P = .003), while in patients with 1 and > or = 2 positive LNs, the survival experience was similar (P = .919 and .182, respectively). A significant difference in survival in patients at stage IIa was observed between group A and group B (P = .005). However, the survival in patients at stage IIb and stage III was not different between the two groups (P = .302 and 0.108, respectively).

CONCLUSIONS

For advanced esophageal carcinoma, if the number of resected LNs per operation is less than 6, an occult positive regional LN might be missed, resulting in an inaccurate N classification. The minimum of 6 LNs removed for esophageal cancer recommended by UICC and AJCC is rational and should be complied with.