Correct Evaluation of the 7th Edition of the TNM Classification for Gastric Cancer?

Abstract

TO THE EDITOR: We read with great interest the article by Warneke et al, which reported that the seventh edition of the International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) TNM classification for gastric cancer has not improved the assessment of patient prognosis compared with the fifth and sixth editions of the UICC/AJCC TNM classification. In contrast, other investigators demonstrated that the seventh edition of the TNM classification for gastric cancer was more suitable for predicting the prognosis of patients after surgery than the previous editions. After a careful analysis of this article’s results, we found several obvious defects which could give rise to bias in the conclusions and which should be addressed in detail. In comparison with patients with gastric cancer, patients with esophagogastric junction tumors could have a more distinctive prognosis, given that these patients were classified as having esophageal cancer according to the seventh edition of the UICC/AJCC TNM classification. In addition, the authors did not provide detailed information to show the number of dissected lymph nodes, which is considered a requirement for curative resection of gastric cancer and radical lymphadenectomy. Actually, 15 or more lymph nodes should be required to determine the accurate pN stage and inhibit stage migration. Lastly, we found that some patients described in this article as having advanced stage cancer only underwent palliative resection and had distant metastasis. These patients must have had a poorer prognosis and could not be evaluated precisely for TNM classification. Strictly speaking, patients with distant metastasis should be excluded from the study.