Chaturvedi Anil K, Mbulaiteye Sam M, Engels Eric A
Viral Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Blvd, EPS 7072, Rockville, MD 20852, USA.
Ann Epidemiol. 2008 Mar;18(3):230-4. doi: 10.1016/j.annepidem.2007.10.005.
Registry-based studies provide valuable data regarding cancer risk among people with HIV/AIDS (PWHA). Such studies utilize the standardized incidence ratio (SIR) to estimate the relative risk (RR), an etiologically relevant measure. However, SIR may underestimate RR when HIV/AIDS prevalence in the general population or RR is high. We quantified the extent of this underestimation for 3 AIDS-related cancers: Kaposi sarcoma (KS), central nervous system non-Hodgkin lymphoma (CNS NHL) and cervical cancer.
We used data on cancer risk among PWHA from the U.S. HIV/AIDS Cancer Match Study. SIRs were compared with RRs estimated using two methods: (1) SIRs calculated using pre-AIDS era (1973-1979) cancer incidence rates (SIRpre-AIDS) and (2) SIRs calculated after subtraction of cancers known to be among PWHA from general population rates (SIRexclusion).
For KS and CNS NHL, SIRs (117.8 and 133.9, respectively) calculated using overall general population rates substantially underestimated both SIRpre-AIDS (19,778 and 3,612, respectively) and SIRexclusion (657.7 and 536.4, respectively). In contrast, the extent of underestimation was negligible for cervical cancer (SIR = 4.9 vs. SIRexclusion = 5.1). For KS and CNS NHL, SIRs were higher in females than in males. However, SIRpre-AIDS and SIRexclusion estimates were more similar, indicating that SIR differences artifactually reflect differences in HIV/AIDS prevalence between males and females. For KS and CNS NHL, trends across calendar time were weaker in SIRs than in SIRpre-AIDS and SIRexclusion.
For KS and CNS NHL, SIRs substantially underestimate RRs. This underestimation arises from the exceptionally high relative risk of KS and CNS NHL among PWHA. SIRs must be interpreted cautiously when HIV/AIDS prevalence is high or varies across groups of interest.
基于登记处的研究提供了有关艾滋病毒/艾滋病患者（PWHA）癌症风险的宝贵数据。此类研究利用标准化发病率比（SIR）来估计相对风险（RR），这是一种病因学上相关的指标。然而，当一般人群中的艾滋病毒/艾滋病患病率或RR较高时，SIR可能会低估RR。我们对三种与艾滋病相关的癌症：卡波西肉瘤（KS）、中枢神经系统非霍奇金淋巴瘤（CNS NHL）和宫颈癌的这种低估程度进行了量化。
我们使用了来自美国艾滋病毒/艾滋病癌症匹配研究中PWHA的癌症风险数据。将SIR与使用两种方法估计的RR进行比较：（1）使用艾滋病前时代（1973 - 1979年）癌症发病率计算的SIR（SIRpre - AIDS），以及（2）从一般人群发病率中减去已知在PWHA中的癌症后计算的SIR（SIRexclusion）。
对于KS和CNS NHL，使用总体一般人群发病率计算的SIR（分别为117.8和133.9）大大低估了SIRpre - AIDS（分别为19,778和3,612）以及SIRexclusion（分别为657.7和536.4）。相比之下，宫颈癌的低估程度可以忽略不计（SIR = 4.9 vs. SIRexclusion = 5.1）。对于KS和CNS NHL，女性的SIR高于男性。然而，SIRpre - AIDS和SIRexclusion估计值更相似，表明SIR差异人为地反映了男性和女性之间艾滋病毒/艾滋病患病率的差异。对于KS和CNS NHL，SIR随日历时间的趋势比SIRpre - AIDS和SIRexclusion中的趋势更弱。
对于KS和CNS NHL，SIR大大低估了RR。这种低估源于PWHA中KS和CNS NHL异常高的相对风险。当艾滋病毒/艾滋病患病率较高或在感兴趣的群体中有所不同时，必须谨慎解释SIR。
