主题：PET/CT在恶性肿瘤中的应用 -- 良金百辟

日本人的无症状人群筛检指南－－不是说用于肿瘤患者的临床应用指南－－的理论基础就是错的，所以我才会说他们错了。

对于乳腺钼靶筛查乳腺癌，我并不反对。只是因为目前找不出更好的办法，并且足够便宜易用。如果PET－CT和钼靶筛查的阳性预测值一样，你选哪个？

AFP和宫颈涂片筛查就没啥争议呀。您当然可以争辩

The sensitivity and specificity of AFP varied widely, and this could not be entirely attributed to the threshold effect

of the different cutoff levels used.

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(Am J Gastroenterol 2006;101:513–523)

Accuracy of Ultrasonography, Spiral CT, Magnetic Resonance, and Alpha-Fetoprotein in Diagnosing Hepatocellular Carcinoma: A Systematic Review

CME

Agostino Colli, M.D.,1 Mirella Fraquelli, M.D., Ph.D.,2 Giovanni Casazza, Ph.D.,3 Sara Massironi, M.D.,1

Alice Colucci, M.D.,1 Dario Conte, M.D.,2 and Piergiorgio Duca, M.D.3

1Department of Internal Medicine, Ospedale “A. Manzoni”, Lecco, 2Postgraduate School of Gastroenterology,

IRCCS Ospedale Maggiore, Milan, and 3Department of Clinical Sciences, Ospedale “L. Sacco”, Milan, Italy

BACKGROUND In patients with chronic liver disease, the accuracy of ultrasound scan (US), spiral computed AND AIM: omography (CT), magnetic resonance imaging (MRI), and alpha-fetoprotein (AFP) in diagnosing hepatocellular carcinoma (HCC) has never been systematically assessed, and present systematic review was aimed at this issue.

METHODS: Pertinent cross-sectional studies having as a reference standard pathological examinations of the explanted liver or resected segment(s), biopsies of focal lesion(s), nd/or a period of follow-up, were identified using MEDLINE, EMBASE, Cochrane Library, and CancerLit. Pooled sensitivity, specificity, and likelihood ratios (LR) were calculated using the random effect model. Summary receiver operating characteristic (SROC) curve and predefined subgroup analyses were made when indicated.

RESULTS: The pooled estimates of the 14 US studies were 60% (95% CI 44–76) for sensitivity, 97% (95% CI 95–98) for specificity, 18 (95% CI 8–37) for LR+, and 0.5 (95% CI 0.4–0.6) for LR; for the 10 CT studies sensitivity was 68% (95% CI 55–80), specificity 93% (95% CI 89–96), LR+ 6 (95% CI

3–12),and LR 0.4 (95% CI 0.3–0.6); for the nine MRI studies sensitivity was 81% (95% CI 70–91), specificity 85% (95%CI 77–93), LR+ 3.9 (95%CI 2–7), and LR 0.3 (95% CI 0.2–0.5). The sensitivity and specificity of AFP varied widely, and this could not be entirely attributed to the threshold effect of the different cutoff levels used.

CONCLUSIONS: US is highly specific but insufficiently ensitive to detect HCC in many cirrhotics or to support an

effective surveillance program. The operative characteristics of CT are comparable, whereas MRI is more sensitive. High-quality prospective studies are needed to define the actual diagnostic role of AFP.

还是老问题，您对适用人群的概念不清楚。

美国人群HBV感染率是多少？肝癌发病率是多少？

AFP筛查早期肝癌的原创性研究是我国科学家提出来的，初始研究在启东等地进行，那里肝癌发病率远高于发达国家。

深感河里水深,如果不仔细准备就发言,是随时可能被揪出来的.

被逼去查资料,受益是大大的,呵呵.

我没有看过laftodeath引用的文章，不过那么大的CI,就怀疑它的样本量很小。我也不知道研究到底是这么做的。不过如果这些数字是可靠的话，那么这个测试在刪查里的实用性就很成问题了。如果检查中真实的癌症患者概率是20%的话，只有40%的阳性结果是真实的。如果概率是70%的话，正确性就提高到85%。

很多网友对sensitivity和specificity不熟悉。我就越俎代庖来解释一下。

sensitivity是指测试能正确指出患者的概率，这里是100%。

specificity是指测试能正确指出非患者的概率，这里是60%。

利用bayes theory, 我们就能估计测试患者真的患病时给测出的概率。

P(+|C)是sensitivity， 100%；

P(-|non-C)是specificity， 60%;

P(+|non-C)=40%

假设患者的概率是1%, P(C)=1%

那么，

P（C|+）就是测试阳性时，真正患者的概率。

P（C|+)=P(+|C)P(C)/P(+)=P(+|C)P(C)/(P(+|C)P(C)+P(+|non-C)P(non-C)=0.01/0.05=20%

这个也就是说当测试是阳性是，只有20%的人是这真正的患者。

这就是问题所在。

即使高龄人群，年发病率在10万分之480左右（IARC），这是需要被查出的比例。2007年日本某文说0。5％，是比较可信的

Type of Participants：The review only examined studies including patients with chronic liver disease (i.e., cirrhosis or chronic hepatitis) assessed with the aim of detecting the possible presence of HCC.

建议您用这篇文章的纳入标准评价一下你看到的研究

另外，请指教： 某诊断指标的敏感度 特异度 与人群有关？

我已经选中两个医生了。

这个意义非常重大。另外两个偏执狂认为这个检查，哪个检查如何。但这些检查，必须是要形成了肿瘤占位后，才有效。

绝大部分肿瘤，等到形成占位并被检查出，就已经太晚了。

PET-CT的显著优势就是可以把仅仅在分子形态出现问题（还不是肿瘤）[B][/B]的组织，查找到。

“宁错杀1000，不放过1个”。

这对挽救生命的意义超然。

毕竟大部分都是专业讨论

我很欣慰。这个思路很好。

您可以去看看我给的体检建议，对于AFP筛检给了什么样的前提，呵呵。

于是你可以继续追问为什么临床医生在所谓的SCI论文里经常会报道：在这个研究中，PET－CT的敏感度、特异度、阳性预测值、阴性预测值分别是blablablabla呢？

呵呵