We mention the analyses of surgical results for gastric carcinoma of Y.Noguchi et al. who try to elucidate factors that might explain the differences in surgical results between Japan and the United States.
This is an important aspect because it has been suggested that the improved prognosis reported in Japan is due to a different gastric tumor from that observed in the US and Europe.
Japanese surgeons explain the better prognosis in their patients with a higher frequency of early stage lesions, less obese patients, and above all greater use of extended lymph node dissection that provides more accurate staging.
Japanese didn't publish randomized studies that demonstrate a beneficial effect of extended surgery (Noguchi) .
In Europe two randomized trials comparing D1 with D2 dissection in patients undergoing potentially curative resection were conducted, one by Medical Research Council in the United Kingdom and the other by the Dutch Gastric Cancer Group in the Netherlands. Both trials found that the rates of short-term morbidity and in-hospital mortality were substantially higher among the patients who underwent D2 dissection (Bonenkamp).
On the contrary Murray F. Brennan in the same number of N Engl J Med explained that in centers where extended lymph node dissection can be performed with lower morbidity and mortality than were found in the D2 group in the study by Bonenkamp et al., surgeons may not be convinced. As long as surgery remains the most effective therapy for gastric adenocarcinoma, extended lymph-node dissection will probably continue to be performed in some centers, if for no other reason than accuracy of staging (Brennan).
In fact radical surgery was a well established procedure at MSKCC in the 1960s, but it was abandoned by most surgeons in the US because of its high morbidity and mortality and an unclear survival benefit. Instead in Japan lymph node dissection up to the N2 lymph nodes became a routine procedure for the treatment of gastric carcinoma and together with widely accepted screening programs that identified more and earlier lesions have resulted in better outcomes than are found in the US and other countries.
MSKCC is one of the few centers in the US in which lymph node dissection (D2) is performed routinely.
Noguchi et al conclude that results of gastric carcinoma treatment comparable to those obtained in Japan can be obtained in Western centers.
Differences in tumor location, a greater frequency of early stage disease, and more accurate staging compared with gastric carcinoma patients in the US explain the more favourable outcome of Japanese patients.
A direct comparison of tumours, stage for stage and location for location would be necessary to prove the hypothesis that gastric carcinoma occurring in Japan and the US is different (Noguchi).
References
Y Noguchi, T Yoshikawa, A Tsuburaya, H Motohashi, M.S. Karpeh, M.F. Brennan. Is Gastric Carcinoma different between Japan and the United States?
Cancer 2000; 89: 2237-46.
JJ Bonenkamp et al. Extended lymph node dissection for gastric cancer. N Engl J Med 1999; 340: 908-14.
A Cuschieri et al. Postoperative morbidity and mortality after D1 and D2 resection for gastric cancer: preliminary results of the MRC randomized controlled surgical trial.
Lancet 1996; 347 :995-9.
JJ Bonenkamp et al. Randomized comparison of morbidity after D1 and D2 dissection for gastric cancer in 996 Dutch patients.
Lancet 1995; 345: 745-8.
M F Brennan. Lymph node dissection for gastric cancer.N Engl J Med 1999; 340: 956-58.
M Sasako. Risk factors for surgical treatment in the Dutch Gastric Cancer trial. Br. J Surg 1997; 84: 1567-71.
