Lymphovenous Canada: Japan leads the way with lymph node dissection to treat gastric cancer

Surgical treatment is only one curable treatment for gastric cancer. It is well known that treatment results in Japan were significantly superior to those in Western countries. Comparing the nationwide registry in Japan (44,962 patients in 1982-84) and the SEER program in USA (4,785 patients in 1979), the five year survival rate (5YSR) was 87% in Japan and 67% in USA for Stage Ib, 77% in Japan and 50% in USA for Stage ll, 64% in Japan and 17% in USA for Stage IIIa. The difference was mainly caused by different attitude of lymph node (LN) dissection. My intention is to explain the scientific background and the latest progress of LN dissection in Japan.

Knowledge of lymphatic channels and regional LN stations is essential for rational LN dissection. Detailed anatomical studies provided the fundamental base. Intra-operative lymphography using India-ink was popularized in 1985. The contrast media was directly injected into the submucosa or peri-gastric LNs, and it demonstrated clearly the all lymphatic channels and LNs from injecting point (Fig. 1,2, and 3). This method was useful to study the lymphatic streams and regional LNs as well as for complete removal of the regional LNs.

Surgical techniques was remarkably improved and it leaded to higher curability and safeness. The Japanese nationwide registry 1991 reported that 5YSR was 87.9% for pN0, 57.7% for pN1, 32.6% for pN2, and 9.6% for pN3. Extent of LN dissection was classified into D0, D1, D2, and D3.D2 (standard lymphadenectomy) means complete removal of pN1 and pN2 (Fig. 4). D3 (extended lymphadenectomy) means complete removal of pN1, pN2, and pN3. D1 (limited or conservative lymphadenectomy) means removed in pN1. The 5YSR was 73.9% for D2, 65.8% for D1, 5I.2% for D3,and 15.7% for D0.

Effectiveness of LN dissection were evaluated by 5YSR of node-positive patients after systematic lymphadenectomy. Furthermore the effectiveness well confirmed by uni-variate and multi-variate analyses. Risks of this treatment was minimal; surgical death was 0.8% for D2, 1.3% for D1, 2.0% for D3, and 1.1'% for D0.

Big new waves are approaching to the shore of LN dissection. The background is the shift of intention from "radicality" to "radicality together with high QOL". The new concept "individualized or order-made surgery" was widely accepted. We have to select the most effective and reasonable surgery for an individual patient. A computer program was in use for this purpose since 1985. The program informs preoperatively the incidence of metastasis at each LN station and expected 5YSR and recurrent sites for an individual patient. Sentinel node navigation and micrometastasis is the latest topic in this field.

In conclusion, I would like to stress that knowledge and technologies of basic science are valuable for development of cancer treatment.