Gastric adenocarcinoma with para-aortic lymph node metastasis: a borderline resectable cancer?

Dissection of the para-aortic lymph nodes (PAN) had once been enthusiastically explored at dedicated centers throughout Japan. Reflecting the results of a randomized trial, however, the current standard surgery for advanced resectable gastric cancer does not include systematic dissection of the PAN. Gastric cancer with PAN metastases, currently considered distant metastases, is classified as Stage IV, and according to the algorithm of the Japanese guidelines, is not indicated for surgery with curative intent. Historical data indicates, however, that a certain proportion of long-term survivors can be introduced among patients with PAN metastasis through D2 + PAN dissection. The Japan Clinical Oncology Group launched a series of phase II trials exploring a strategy employing neoadjuvant chemotherapy followed by D2 + PAN dissection for patients radiologically diagnosed to harbor metastases to the PAN. The campaign was successful, with 57 % of these patients surviving for 5 years after two cycles of neoadjuvant S-1/CDDP followed by surgery. This strategy is now the tentative standard, mentioned in the 4th version of the Japanese Gastric Cancer Treatment Guidelines as one of the current clinical questions, and could be replaced by a more powerful combination chemotherapy or treatment employing more or longer cycles of chemotherapy in the future. The relevance of the strategy consisting of neoadjuvant chemotherapy followed by D2 + PAN dissection and its fundamental difference from the concept of conversion therapy are discussed herein with reference to the literature.