Neoadjuvant chemotherapy for patients with locally advanced gastric carcinoma - Effect on tumor cell microinvolvement of regional lymph nodes

BAGKGROUND, In a previous study the authors demonstrated, using immunohisto chemical methods for epithelial antigens, that the regional lymph nodes of gastric adenocarcinoma contained individual tumor cells or small clusters o f these cells (tumor cell microinvolvement [TCM]) in over 90% of cases. In the current study the authors used the same method to investigate a series of gastric adenocarcinoma cases treated with neoadjuvant chemotherapy prior to tumor resection; their aim was to determine the effect of chemotherapy on TCM in regional lymph nodes. METHODS. Resection specimens from 17 patients with adenocarcinoma of the st omach, resected after neoadjuvant treatment and classified by routine histo logy as ypN0, were included in this study. One section from each of the 622 lymph nodes dissected from these specimens was stained by immunohistochemi cal methods for cytokeratins and Ber-Ep4. RESULTS, Six patients (35%) and 25 of the 622 lymph nodes (4.0%) had TCM, c ompared with 93% of patients and 21.8% of lymph nodes in the previous study of patients treated with surgery alone. The lymph node response to chemoth erapy correlated with the pathologic response of the primary tumor. Specifi cally, none of 5 patients with a complete or major pathologic response vers us 6 of 12 (50%) patients with minor, partial, or no response had lymph nod e microinvolvement. CONCLUSIONS, In comparison to our previous study, this study indicates that chemotherapy has a marked effect on tumor cells in regional lymph nodes an d that the extent of this effect can be correlated with the degree of patho logic response of the primary tumor to chemotherapy. (C) 1999 American Canc er Society.