据5月5日刊JAMA上的一则研究披露，在过去的30年中，各个年龄组和族裔中的某种类型的胃癌发病率有所下降，但25-39岁年龄组的白人例外。在本期杂志的另外一篇报告中，基于从前研究的分析发现，那些在胃癌手术后接受化疗的患者比那些仅接受外科治疗的患者有着更高的存活率。
在全世界范围内，胃癌是排第四的最常见的癌症，它也是癌症死亡率排第二的最常见癌症。根据由National Cancer Institute, Rockville, Md.的William R. Anderson, M.D.及其同僚所做的一项研究中的背景资料，与食道比邻的胃上部的贲门肿瘤可能与胃食道返流有关，但大多数的非贲门癌与幽门螺旋杆菌的慢性粘膜感染有关。
研究人员分析了美国的基于年龄特异性的非贲门胃癌的数据，（使用的是来自National Cancer Institute's Surveillance, Epi-demiology, and End Results Program的数据）该数据所涵盖的是约26%的美国人口。从1977年到2006年，共有8万3225例新发的成人原发性胃癌，其中包括3万9003例非贲门癌病例。
文章的作者发现，每10万人中的总体年龄标准化年发病率在研究期间从5.9下降至4.0（白人）、从13.7下降至9.5（黑人）以及从17.8下降至11.7（其他族裔）。 “在老年和年轻白人中的年龄特异性趋势有着相当大的差别：每10万人的发病率从19.8显著下降至12.8（60-84岁）、从2.6下降至2.0（40-59岁），但该发病率在25-39岁年龄组则从0.27上升至0.45。相反，在黑人和其他族裔中，所有年龄组的发病率或是有所下降，或是处于稳定状态。年龄-阶段-组群分析证实，在自1952年出生的较年轻的白人组群中，该发病率有了显著的增加。”
推荐原文出处：
JAMA. 2010;303(17):1723-1728.
Age-Specific Trends in Incidence of Noncardia Gastric Cancer in US Adults
William F. Anderson, MD; M. Constanza Camargo, MSc; Joseph F. Fraumeni Jr, MD; Pelayo Correa, MD; Philip S. Rosenberg, PhD; Charles S. Rabkin, MD
Context For the last 50 years, overall age-standardized incidence rates for noncardia gastric cancer have steadily declined in most populations. However, overall rates are summary measures that may obscure important age-specific trends.
Objective To examine effects of age at diagnosis on noncardia gastric cancer incidence trends in the United States.
Design, Setting, and Participants Descriptive study with age-period-cohort analysis of cancer registration data from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program, which covers approximately 26% of the US population. From 1977 through 2006, there were 83 225 adults with incident primary gastric cancer, including 39 003 noncardia cases.
Main Outcome Measures Overall and age-specific incidence rates, adjusted for period and cohort effects using age-period-cohort models. Results were stratified by race, sex, and socioeconomic status.
Results Overall age-standardized annual incidence per 100 000 population declined during the study period from 5.9 (95% confidence interval [CI], 5.7-6.1) to 4.0 (95% CI, 3.9-4.1) in whites, from 13.7 (95% CI, 12.5-14.9) to 9.5 (95% CI, 9.1-10.0) in blacks, and from 17.8 (95% CI, 16.1-19.4) to 11.7 (95% CI, 11.2-12.1) in other races. Age-specific trends among whites varied significantly between older and younger age groups (P & .001 for interaction by age): incidence per 100 000 declined significantly from 19.8 (95% CI, 19.0-20.6) to 12.8 (95% CI, 12.5-13.1) for ages 60 to 84 years and from 2.6 (95% CI, 2.4-2.8) to 2.0 (95% CI, 1.9-2.1) for ages 40 to 59 years but increased significantly from 0.27 (95% CI, 0.19-0.35) to 0.45 (95% CI, 0.39-0.50) for ages 25 to 39 years. Conversely, rates for all age groups declined or were stable among blacks and other races. Age-period-cohort analysis confirmed a significant increase in whites among younger cohorts born since 1952 (P & .001).
Conclusions From 1977 through 2006, the incidence rate for noncardia gastric cancer declined among all race and age groups except for whites aged 25 to 39 years, for whom it increased. Additional surveillance and analytical studies are warranted to identify risk factors that may explain this unfavorable trend.
