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World J Gastrointest Oncol. Feb 15, 2012; 4(2): 16-21
Published online Feb 15, 2012. doi: 10.4251/wjgo.v4.i2.16
Lymph node, peritoneal and bone marrow micrometastases in gastric cancer: Their clinical significance
John Griniatsos, Othon Michail, Nikoletta Dimitriou, Ioannis Karavokyros
John Griniatsos, Othon Michail, Nikoletta Dimitriou, Ioannis Karavokyros, 1st Department of Surgery, University of Athens, Medical School, GR 115-27, Athens, Greece
Author contributions: Michail O and Dimitriou N substantially contributed to the conception and design of the study, analyzed and interpreted the data; Karavokyros I critically reviewed the article, making useful comments; Griniatsos J drafted the article and made several revisions; All authors approved the final version to be published.
Correspondence to: John Griniatsos MD, Assistant Professor of Surgery, 1st Department of Surgery, University of Athens, Medical School, LAIKO Hospital, 17 AgiouThoma str, GR 115-27, Athens, Greece. johngriniatsos@yahoo.com
Telephone: +30-210-7456855 Fax: +30-210-7771195
Received: May 16, 2011
Revised: October 3, 2011
Accepted: October 12, 2011
Published online: February 15, 2012

The 7th TNM classification clearly states that micrometastases detected by morphological techniques (HE stain and immunohistochemistry) should always be reported and calculated in the staging of the disease (pN1mi or M1), while patients in whom micrometastases are detected by non-morphological techniques (e.g., flow cytometry, reverse-transcriptase polymerase chain reaction) should still be classified as N0 or M0. In gastric cancer patients, micrometastases have been detected in lymph nodes, the peritoneal cavity and bone marrow. However, the clinical implications and/or their prognostic significance are still a matter of debate. Current literature suggests that lymph node micrometastases should be encountered for the loco-regional staging of the disease, while skip lymph node micrometastases should also be encountered in the total number of infiltrated lymph nodes. Peritoneal fluid cytology examination should be obligatorily performed in pT3 or pT4 tumors. A positive cytology classifies gastric cancer patients as stage IV. Although a curative resection is not precluded, these patients face an overall dismal prognosis. Whether patients with a positive cytology should be treated similarly to patients with macroscopic peritoneal recurrence should be evaluated further. Gastric cancer cells are detected with high incidence in the bone marrow. However, the published results make comparison of data between groups almost impossible due to severe methodological problems. If these methodological problems are overcome in the future, specific target therapies may be designed for specific groups of patients.

Keywords: Gastric cancer, D2 lymphadenectomy, Lymph node micrometastases, Peritoneal micrometastases, Bone marrow micrometastases