Purpose: Lung cancer is still leading cause of cancer death in Germany with more than 40.000 deaths per year. For men it’s number one cause of cancer death, with a falling tendency during the last 10 years. For women it’s the second most cause of cancer death with a strong tendency to rise. The 5-year survival rate in Germany is 15% for men and 18% for women.[1] For non-advanced stages surgery is the main option for therapy. Our aim was to review the quality of clinical trials systematically and to summarize the evidence on this topic.
Method: A literature search was performed for prospective randomised controlled trials of adjuvant chemotherapy given because of non-small cell lung cancer. It was systematically searched in Medline and Cochrane Library from January 1980 until June 2011 with predefined search terms. Articles were selected by a two-step procedure. Each study was assessed according to their methodically quality using “Level of evidence” from Oxford Centre for Evidence-based Medicine. The relevant data of each study were extracted by two scientists independently. If the two assessments differed a consensus decision of the two reviewers was reached. Then a meta-analysis of Level 1 trials and from Level 1 together with Level 2 was performed by Review Manager (RevMan) 5.1. The common endpoint is overall survival. For comparison hazard ratio was used to show effects in forest plot. For studies without hazard ratios a calculation of the estimated hazard ratio from Kaplan-Meier curve was performed and the Parmar method was used. [2]
Result: The search identified 228 trials comparing adjuvant chemotherapy with surgery only. The meta-analysis codedadjuvant chemotherapy as experimental and included 28 studies of level 1 and 2 (involving 10403 patients). 12 of them had the highest evidence level 1 (6659 patients). The summary hazard ratio for level 1 studies is HR 0.88 (95%-confidence interval 0.82 - 0.95) with test for overall effect p< 0.001 (see figure below). For all studies 0.87 (95-%-confidence interval 0.83 - 0.93) with p < 0.001.
Conclusion: This meta-analysis showed a significant benefit for adjuvant chemotherapy compared to surgery alone. [1] Statistisches Bundesamt Deutschland, Wiesbaden (2007) [2] Parmar, K. M. , et al. Stat. Med. 17, 2815-2834 (1998)
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