Avenues - Winter 2004

Meta-Analysis Results Awaiting Publication

In last winter’s Avenues, we announced the launch of two important meta-analyses involving lung cancer and liver cancer. Since then, we have systematically reviewed all known clinical trials on the use of Chinese herbal medicine in combination with standard therapy. Today, we are analyzing the final results and are about to publish our findings in a major peer-reviewed medical journal.

BACKGROUND ON THESE META-ANALYSES
The amount of clinical evidence being published on the use of Chinese herbal medicine in combination with standard therapy is increasing every year.For centuries in China, textbooks have discussed treatment strategies handed down in the oral and literary tradition of Chinese herbal therapy. Over the past fifty years, modern Chinese-language medical journals have more formally assessed the effectiveness of these treatment strategies; from case reports came observational studies and, over the last decade, randomized, controlled trials. Although these medical journals report only studies from the past fifty years, these data represent a distillation of the accumulated historical experience of the body of traditional Chinese medicine. The field is growing rapidly, from just a few hundred published randomized, controlled trials of Chinese herbal medicine in 1984, to many thousands in 2004.

Online availability of the Chinese-language TCMLARS database (Traditional Chinese Medicine Language Acquisition and Retrieval System, www.cintcm.ac.cn) helps to make our meta-analyses possible. Until recently, time-consuming searches by hand were the only means of accessing Chinese-language data sources. This database now allows rapid searching of journal abstracts to quickly locate clinical trials data published in China after 1984. TCMLARS contains more than 400,000 references and abstracts to literature on traditional Chinese medicine, drawn from more than 600 Chinese biomedical journals and 100 specialty journals. Because a vast majority of the clinical studies of herbal medicine in cancer treatment only appear in Chinese-language journals, the Pine Street Foundation's in house language abilities have proved to be an invaluable asset in accomplishing these meta-analyses.

LUNG CANCER META ANALYSIS
The lung cancer meta-analysis study investigated two specific research questions. First, we looked at the effectiveness of herbal medicine alone compared to platin-based chemotherapy alone (platins are a class of chemotherapy drug) in patients with non-small cell lung cancer. This portion of the project analyzed studies that directly compared Chinese herbal medicine with platin-based chemotherapy; these studies assessed whether Chinese herbal medicine could serve as a substitute for chemotherapy. Such a study design was ethically possible because chemotherapy for non-small cell lung cancer in many cases offers only a modest improvement in long-term survival. Second, we looked at studies that offered patients either herbal medicine in combination with platin-based chemotherapy compared to studies that only used platin-based chemotherapy alone. These studies assessed whether Chinese herbal medicine could enhance the effectiveness of platin-based chemotherapy.

In both the herbal medicine-alone studies and the herbal-chemotherapy combined studies, effectiveness of Chinese herbal medicine for non-small cell lung cancer was assessed by patient survival, tumor response, and quality of life. In the herbal-chemotherapy combined studies, effectiveness was additionally assessed by reduction in chemotherapy toxicity. In total, the lung cancer project analyzed the results of 55 randomized controlled studies, most of which were first published in China.

LIVER CANCER META ANALYSIS
The liver cancer meta-analysis project had the same study design as the lung cancer meta-analysis above and, to date, has analyzed the results of 46 randomized controlled studies on the treatment of primary liver cancer with Chinese herbal medicine. This meta-analysis similarly included studies that compared chemotherapy alone to Chinese herbal medicine alone as well as studies that compared chemotherapy alone to chemotherapy combined with Chinese herbal medicine. The studies analyzed were also first published in China.

WHAT ABOUT THE ISSUE OF STUDY QUALITY?
An important component of the Pine Street Foundation's mission is to help improve the quality of research on complementary and alternative medical treatments for cancer. A central question being addressed in these meta-analyses is the quality of reporting in clinical studies published in Chinese medical journals. Published studies from China are often found to be more highly condensed than typical articles published in the Western literature with key details of study design often omitted, especially details concerning the blinding of subjects and clinicians.

But no clinical study is perfect and problems with study quality are not limited only to those coming from China. As recently as 1994, for example, 70% to 80% of studies published in Western journals did not adequately describe the essential process of how patients were randomly assigned to the treatment drug or the control group.1 By including an assessment of study quality in these meta-analyses, we hope to draw additional attention to this issue.

Look for detailed results of these meta-analyses in an upcoming issue of Avenues.

References:
1. Williams, D. H. and C. E. Davis (1994). “Reporting of assignment methods in clinical trials.” Control Clin Trials 15(4): 294-8.

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