RESPONSE TO LETTER Reply to Letter: “Lymph Node Ratio for Gastric Cancer: Useful Instrument or Just an Expedient to Retrieve Less Lymph Nodes?” Reply:


e really appreciate Dr Rosa’s critical review and the interesting viewpoints regarding our study of incorporating lymph node ratio into the gastric cancer staging system (TNrM).1 Using our definition of misclassification, 57% of patients were misclassified by the seventh American Joint Committee on Cancer (AJCC) staging system and 12% of patients were misclassified by the TNrM staging system. Thus, the proposed TNrM system is likely more accurate than the AJCC system in the staging of gastric cancer patients in the Surveillance Epidemiology and End Results database. The use of this new TNrM staging system may aid oncologists in better predicting survival, making treatment decisions, and comparing cohorts of patients, especially those undergoing more limited lymph node analysis. As we all knew, the number of lymph nodes examined relies heavily on controllable factors such as the scope of surgeons’ dissection; pathologists and pathology technicians who recover lymph nodes; and uncontrollable

factors such as age, gender, ethnicity and tumor characteristics. It is important to get 16 or more lymph nodes to avoid understaging patients, but the reality is that more than 50% of patients who received gastrectomy in the United States do not meet the criteria. The TNrM staging system provided one possible solution to address the dilemma. Rosa et al is afraid that surgical oncologists will start considering TNrM staging system as a “parachute” in case of inadequate node dissection. However, it is hard to assess the “adequacy” of lymph node dissection. Using 16 lymph nodes as an indicator for adequacy of lymph node dissection will oversimplify the problem and is not an optimal solution. In colon cancer surgery, the adequacy of surgery is defined as “An appropriate lymph node resection should extend to the level of the origin of the primary feeding vessel. In all cases for cure, the lymph node resection should be radical and the lymph nodes should be removed en bloc.”2 In rectal cancer surgery, it is required to follow the “Holy” plane while performing the mesorectum resection.3 Therefore, our attention should focus on developing a guideline for gastric cancer lymphadenectomy. To avoid the inadequacy of lymphadenectomy, gastric cancer surgeons should follow the following principles: 1. Lymphadenectomy and gastrectomy should be en bloc whenever is possible to warrant the removal of all the lymph nodes and lymphatic tracts. “Cherry pick” lymph adenectomy should be avoided whenever it is possible.

2. The surgeon should make an effort to trace the named vessels (right gastroepiploic artery and left and right gastric arteries) to the origin to achieve high ligation. 3. Tissues around the proper hepatic artery, medial portion of portal vein, infra hepatic inferior vena cava, common hepatic artery, and proximal proper hepatic artery should be resected. In summary, compared with AJCC TNM staging system, the TNrM staging system provides a more accurate estimate of patients’ prognosis, especially for those patients with less than 16 lymph nodes examined. Gastric surgeons should follow oncologic principles to avoid inadequate lymphadenectomy, which should not merely be measured by the number of lymph nodes examined. Jiping Wang, MD, PhD Division of Surgical Oncology Brigham and Women’s Hospital Boston, MA [email protected]; [email protected]

REFERENCES 1. Wang J, Dang P, Raut C, et al. Comparison of a lymph node ratio-based staging system with the 7th AJCC system for gastric cancer: analysis of 18,043 patients from the SEER database. Ann Surg. 2012;255:478–485. 2. Nelson H, Petrelli N, Carlin A, et al. Guidelines 2000 for colon and rectal cancer surgery. J Natl Cancer Inst. 2001;93:583–596. 3. Heald RJ. The “Holy Plane” of rectal surgery. J R Soc Med. 1988;81:503–508.

Disclosure: There are no conflicts of interest to claim and this study was not supported by any grant. C 2013 by Lippincott Williams & Wilkins Copyright  ISSN: 0003-4932/13/25904-e0066 DOI: 10.1097/SLA.0000000000000315

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Annals of Surgery r Volume 259, Number 4, April 2014

Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

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