Meta_Analysis在肿瘤循证医学中的应用_英文(5)

Chin J Clin Oncol (2008) 5: 1~9

14% (RR= 0.86; 95% CI=0.79~0.94) when performed over 10 years. Rosman and Korsten[34] analyzed thirty studies in which meta-analysis of CT colonography was used. The results showed that CT colonography has a rea-sonable sensitivity and specificity for detecting large polyps, but was less accurate than endoscopic colo-noscopy for smaller polyps. Thus, CT colonography may not be a reasonable alternative in situations in which a small polyp may be clinically relevant. Therapy The benefits of early chemotherapy in asymptomatic metastatic colorectal cancer were analyzed by Ack-land et al.[35] There was no difference in overall qual-ity of life or its individual domains between the two treatment strategies (immediate or delayed treatment at onset of predefined symptoms) at baseline, or at any subsequent time point. Early treatment of asymp-tomatic patients with metastatic colorectal cancer did not provide a survival benefit or improved quality of life compared to withholding treatment until symp-toms occurred. Bonjer et al.[36] performed a meta-analysis of trials randomizing patients with colon cancer to laparoscop-ically assisted or open colectomy. They confirmed that laparoscopically assisted colectomy for cancer is safe. mortality in a meta-analysis. The meta-standardized mortality ratio for liver cancers other than angiosar-coma was 1.35 (95% CI=1.04~1.77). Shi et al.[40] analyzed 32 case-control studies in-volving 3,201 patients with liver cancer and 4,005 controls, identified from a computer-based literature search from 1966 to 2004 in China. The pooled OR for HBsAg (hepatitis B surface antigen) positiv-ity was 14.1 (95% CI=10.6~18.8); for anti-HCV (HCV=hepatitis C virus)/HCV RNA positivity was 4.6 (95% CI=3.6~5.9) and positivity for both HB-sAg and anti-HCV/HCV RNA was 35.7 (95% CI= 26.2~48.5). Hepatitis B virus and Hepatitis C virus infections are main independent risk factors and in China act as synergists for hepatocellular carcinoma (HCC) if both are positive. ScreeningDe Masi et al.[41] evaluated the benefits of screening for hepatocellular carcinoma. The available screen-ing tests to detect hepatocellular carcinoma are alpha-fetoprotein and ultrasound with reported sensitivity and specificity of 50~85% and 70~90%, respectively. Although screening for the early detection of hepa-tocellular carcinoma has become quite common in clinical practice, its effectiveness remains controver-sial due to possible lead-time bias.

Therapy

Evidence-Based Oncology for Liver Cancer

EtiologyOverweight and obesity have shown a weak associa-tion with liver cancer risk. Larsson and Wolk[37] used meta-analysis to analyze 11 cohort studies and found that if normal weight is employed as a reference group, the summary RRs of liver cancer were 1.17 (95% CI=1.02~1.34) for those who were overweight, and 1.89 (95% CI=1.51~2.36) for those who were obese. Excess body weight is associated with an in-creased risk of liver cancer. Based on a meta-analysis conducted by Larsson and Wolk[38] on 4 cohort and 5 case-control stud-ies, involving 2,260 cases and 239,146 controls, the results suggested that an increased consumption of coffee may reduce the risk of liver cancer. The sum-mary RRs of liver cancer for an increase in consump-tion of 2 cups of coffee per day were 0.56 (95% CI= 0.35~0.91) and 0.69 (95% CI=0.55~0.87) respec-tively for persons with or without a history of liver disease. Boffetta et al.[39] analyzed the association between occupational exposure to vinyl chloride and cancer There is no standard treatment for patients with un-resectable HCC. Llovet and Bruix[42] analyzed 14 randomized controlled trials assessing arterial embo-lization (7 trials, 545 patients) or tamoxifen (7 trials, 898 patients). Arterial embolization improved 2-year survival compared with the controls (OR=0.53; 95% CI=0.32~0.89; P=0.017). Sensitivity analysis showed a significant benefit of chemoembolization with cis-platin or doxorubicin (OR, 0.42; 95% CI=0.20~0.88), but none with embolization alone (OR, 0.59; 95% CI=0.29~1.20). Tamoxifen showed no antitumoral effect and no survival benefits (OR, 0.64; 95% CI=0.36~1.13; P=0.13). The authors conclude that chemoembolization improves survival of patients with unresectable HCC and may become the standard treatment. Laparoscopic surgery for hepatic neoplasms aims to provide curative resection while minimizing complications. In a meta-analysis, Simillis et al.[43] reported that laparoscopic resection results in re-duced operative blood loss and earlier recovery with oncologic clearance comparable with open surgery. When performed by experienced surgeons in selected patients, it may be a safe and feasible option. Although transarterial chemoembolization im-

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