Extensive lymph-node dissection in gastric cancer: is it of therapeutic value?

Despite a marked decline in its incidence, gastric cancer remains the second most common cause of cancer-related deaths worldwide. More radical surgical procedures have been introduced and assessed as most patients die from locoregional tumour recurrence after intended curative resection. Many, mainly Japanese and some Western surgeons, believe that the leading cause of local treatment failure is the insufficient nodal clearance. On the other hand, many surgeons in the West regard the lymph nodes as indicators rather than determinants of the disease. According to this view, extensive resection mainly improves the accuracy of the tumour staging and not survival. As a consequence, the extent of lymph-node dissection is a highly controversial issue. Lymphatic spread has long been recognized as a major prognostic factor in gastric cancer. However, the different staging systems that are practised in Japan and the West confuse the comparison of survival results. According to the Japanese Research Society for the Study of Gastric Cancer (JRSGC) (I), the upper abdominal lymph nodes are numbered from 1 to 16 and subsequently grouped into four levels, designated Nl-N4. The grouping into levels depends on the location of the primary tumour, and relates to increasing anatomical distance from the stomach. Dissection of the first level (Nl) of lymph nodes, those directly attached to the stomach, is referred to as Dl dissection; in extended lymph-node disseciton (D2), the second-level (N2), those surrounding the vessels of the celiac axis and in the splenic hilum, are removed. Even wider dissections (D3 or D4) are practised in Japan, but only for patients with suspected invasion of these lymph-nodes levels (N3 or N4). In the Western countries, the tumour nodes metastases (TNM) staging system of the International Union Against Cancer (UICC) is used for the classification of lymph-node involvement (2). Pathologically-assessed involved lymph nodes are classified in pN-categories: pN0, nodes without metastases; pN1, metastases