The National Cancer Data Base report on poor survival of US gastric carcinoma patients treated with gastrectomy - Fifth edition American Joint Committee on Cancer staging, proximal disease, and the "different disease" hypothesis

BACKGROUND. A high proportion of U.S. patients with gastric carcinoma do no t receive surgical treatment. To sharpen staging criteria and facilitate co mparisons with surgical series, an analysis of patients whose treatment inc luded gastrectomy was undertaken. In addition, to evaluate the "different d isease" hypothesis as an explanation for superior Japanese results, outcome s for Japanese Americans were examined. METHODS. Data were obtained from National Cancer Data Base (NCDB) reports o f 50,169 gastric carcinoma cases diagnosed during the years 1985-1996 and t reated with gastrectomy. In addition to demographic and treatment informati on, 5-year and 10-year relative survival rates are presented, with stage de fined according to fifth edition American Joint Committee on Cancer (AJCC) staging procedures. RESULTS. Stage-stratified 5-year and 10-year relative survival rates were a s follows: Stage IA, 78%/65%; Stage IB, 58%/42%; Stage II, 34%/26%; Stage I IIA, 20%/14%; Stage IIIB, 8%/3%; and Stage IV, 7%/5%. Stage-stratified surv ival for Japanese Americans was higher. Males had a poorer prognosis than f emales, and the male-to-female ratio for Japanese Americans was lower. Prox imal tumors were associated with a worse prognosis than distal tumors; the proportion of Japanese Americans with proximal disease was less than in the overall patient group. Japanese Americans underwent resection of adjacent organs less frequently. In this series, adjuvant therapy did not substantia lly affect survival. Overall, 20% were 10-year survivors; of these, 67% wer e lymph node negative and 98% had less than or equal to 8 involved lymph no des. Five-year stage-stratified survival increased for cases with greater t han or equal to 15 lymph nodes analyzed. Stage migration was evident in cas es with less than or equal to 15 nodes examined. CONCLUSIONS. The current AJCC/International Union Against Cancer TNM stagin g system fails to accommodate the effect of proximal location on prognosis. Largely because Japanese Americans present with fewer proximal tumors, hav e a lower male-to-female ratio, and undergo adjacent organ resection less f requently, stage-stratified survival for Japanese Americans appears to be s uperior. In the U.S., surgical under-treatment of patients with this diseas e appears to be a problem. (C) 2000 American Cancer Society.