医脉通编译，转载请务必注明出处
2015年ASCO年会于5月29日—6月2日在美国芝加哥召开。5月30日下午消化系统（结直肠）肿瘤口头报告专场上，一项摘要号为3504的以人群为基础的研究，对将阿司匹林作为二级预防在未选定的25664名结直肠癌队列中的影响进行探索。医脉通整理如下：
阿司匹林（乙酰水杨酸）的定期使用与降低结肠癌（CRC）发病和死亡相关。然而，由于严重出血副作用的风险，在普通人群中将阿司匹林使用作为主要预防仍存在争议。与此相反，CRC患者中将阿司匹林应用作为二级预防从风险-获益前瞻性上可能更为合理，而且研究人员也观察到阿司匹林在已证明的结直肠癌中可逆转肿瘤逃避机制。本项研究旨在一项大型队列中探讨CRC诊断后阿司匹林应用与CRC-特异性生存期（CSS）和总生存期（OS）之间的关系。
研究方法：
一项观察性以人群为基础的前瞻性队列研究，是在2004年到2011年（挪威癌症登记处）诊断为CRC患者中进行，在这群相同患者中应用阿司匹林（挪威处方数据库）。这个登记处覆盖了超过99%的挪威人口，包括所有以随机选择方式的病例。暴露定义为CRC诊断后接受阿司匹林处方6个月以上。多变量Cox比例风险和竞争性风险分析用来建模生存期。该项研究的主要预后指标是CSS和OS。
研究结果：
在研究期间一共有25644例患者诊断为CRC，其中6109例定义为CRC诊断后阿司匹林暴露。中位随访期是2.2年。在阿司匹林暴露病例中（n=6109），一共有2088例（34.2%）死亡，记录显示1172例（19.2%）是CRC-特异性。在未暴露的阿司匹林病例（n=19535）中，7595例（38.9%）死亡，记录显示6356例（33.5%）是CRC-特异性。多变量分析显示，CRC诊断后阿司匹林暴露独立地与改善的CSS（风险比[HR]，0.53；95%置信区间[CI]，0.50～0.57；P＜0.001）和OS（HR，0.71；95% CI，0.68～0.75；P＜0.001）相关。
结论：
结直肠癌确诊后，阿司匹林暴露独立地与CRC-特异性生存期和总生存期的改善相关。
会议专题》》》2015年ASCO年会专题报道
阅读摘要原文
Impact of aspirin as secondary prevention in an unselected cohort of 25,644 patients with colorectal cancer: A population-based study.（Abstract 3504）
Authors：Simer Bains, Milada Mahic,et al.
Session Type：Oral Abstract Session
Background：Regular use of aspirin (acetylsalicylic acid) has been associated with reduced incidence and mortality of colorectal cancer (CRC). However, the use of aspirin as primary prevention in the general population is still being debated due to the risk of serious hemorrhagic side effects. In contrast, the use of aspirin as secondary prevention in patients with CRC may be more justified from a risk-benefit prospective, and also as we have observed that aspirin reverses tumor immune evasion mechanisms in established colorectal cancer. This study was conducted to examine the association between aspirin use after diagnosis of CRC with CRC-specific survival (CSS) and overall survival (OS) in the largest cohort ever examined.
Methods：An observational population-based retrospective cohort study was undertaken by linking patients diagnosed with CRC from 2004 through 2011 (Cancer Registry of Norway) with the use of aspirin in the same patients (The Norwegian Prescription Database). The registries used cover more than 99% of the Norwegian population, and include all cases in an unselected manner. Exposure was defined as having received prescription for more than 6 months of aspirin after diagnosis of CRC. Multivariate Cox proportional hazard and competing risk analyses were used to model survival. The main outcome measures of the study were CSS and OS.
Results：In total, 25,644 patients were diagnosed with CRC in the study period and 6,109 of them were defined as exposed to aspirin after the diagnosis of CRC. The median follow-up was 2.2 years. Among aspirin exposed cases (n = 6,109), a total of 2,088 (34.2%) deaths were recorded of which 1,172 (19.2%) were CRC-specific. Among non-exposed aspirin cases (n = 19,535), a total of 7,595 (38.9%) deaths were recorded of which 6,356 (33.5%) were CRC-specific. In multivariate analysis, aspirin exposure after the diagnosis of CRC was independently associated with improved CSS (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.50-0.57; p < 0.001) and OS (HR, 0.71; 95% CI, 0.68-0.75; p < 0.001).
Conclusions：Exposure to aspirin after the diagnosis of CRC is independently associated with improved CSS and OS.
