Is it time for a new TNM classification in esophageal carcinoma?

PURPOSE: To investigate the importance of lymph node yield (LNY) and the ratio of afflicted lymph nodes in esophageal carcinoma patients. PATIENTS AND METHODS: Between 1992 and 2004, 368 patients with esophageal carcinoma underwent surgery. Esophagectomy with curative intent was performed in 255 patients. Subtotal esophagectomy was performed either by thoracoabdominal (104 patients, 40.8%) or by transhiatal approach (151 patients, 59.2%).
RESULTS: According to the LNY, patients were grouped into 3 groups. Twenty-six patients had < or =5, 96 had 6 to 18, and 113 had > or =19 dissected lymph nodes. In patients with nodal involvement (pN1), no significant overall survival differences were identified when stratifying subgroups according to the LNY. However, LNY had striking prognostic relevance in pN0 patients. The median overall survival was 23 (< or =5 LN), 36 (6-18 LN), and 88 months (> or =19). Even for patients with tripled LNY than the proposed minimum by the International Union Against Cancer (UICC) (18 LN), the rate of patients with detected lymph node metastases was only 46%, compared with 61% for patients with a LNY of > or =19 (P = 0.002). In pN1 patients classified according to the ratio of afflicted lymph nodes, median overall survival was 27 months in patients with a ratio <11%, compared with 15 and 13 months in patients with a ratio of 11% to 33% and >33%, respectively (P < 0.001). Multivariate Cox regression modeling identified ratio as the strongest independent prognostic factor for overall survival in pN1 and the LNY in pN0 patients.
CONCLUSIONS: The minimal regional LNY of 6 lymph nodes as recommended by the UICC for esophageal carcinoma is far too low to appropriately stage the disease. The LNY and the ratio should be reflected in the next version of the UICC classification.