Racial factors cannot explain superior Japanese outcomes in stomach cancer

To compare the stage-stratified survival of Japanese patients treated in Honolulu according to Western techniques with that of Japanese patients treated in Tokyo according to Japanese techniques, thus eliminating race as a potentially confounding variable.

Of 312 Honolulu Japanese patients surviving Western-type gastric resection for neoplasm between 1974 and 1985, 279 were identified with invasive gastric adenocarcinoma unassociated with any second malignancy. This Honolulu cohort, treated by Western methods, was retrospectively compared with a similar, previously described cohort of 3176 Tokyo Japanese patients treated according to Japanese methods.

American Joint Committee on Cancer/Union Internationale Contre le Cancer criteria for stage-stratified survival.

Despite non-TNM prognostic factors favoring higher survival for the Honolulu Japanese patients, for every TNM stage, we observed higher survival for the Tokyo Japanese patients who were treated according to Japanese techniques. For stage I disease, the survival rates were 86% vs 96%, respectively (P < .001); for state II, 69% vas 77% (P = .15); for stage III, 21% vs 49% (P < .001); and for stage IV, 4% vs 14% (P < .001).

Because all patients in this study are Japanese, race-related factors or the "different-disease" hypothesis cannot explain these results. Lymphadenectomy-related stage-migration and/or differing therapeutic efficacy seem more likely explanations.