Jezierski Tadeusz, Walczak Marta, Ligor Tomasz, Rudnicka Joanna, Buszewski Bogusław
Department of Animal Behaviour, Institute of Genetics and Animal Breeding of Polish Academy of Sciences, Jastrzębiec, O5-552 Magdalenka, Poland.
J Breath Res. 2015 May 6;9(2):027001. doi: 10.1088/1752-7155/9/2/027001.
Experimental studies using trained dogs to identify breath odour markers of human cancer, published in the recent decade, have been analyzed and compared with the authors' own results. Particular published studies differ as regards the experimental setup, kind of odour samples (breath, urine, tumor tissue, serum), sample collection methods, dogs' characteristics and dog training methods as well as in results presented in terms of detection sensitivity and specificity. Generally it can be stated that trained dogs are able to distinguish breath odour samples typical for patients with lung cancer and other cancers from samples typical for healthy humans at a 'better than by chance' rate. Dogs' indications were positively correlated with content of 2-pentanone and ethyl acetate (r = 0.97 and r = 0.85 respectively) and negatively correlated with 1-propanol and propanal in breath samples (r = -0.98 and -0.87 respectively). The canine method has some advantages as a potential cancer-screening method, due to its non-invasiveness, simplicity of odour sampling and storage, ease of testing and interpretation of results and relatively low costs. Disadvantages and limitations of this method are related to the fact that it is still not known exactly to which chemical compounds and/or their combinations the dogs react. So far it could not be confirmed that dogs are able to sniff out early preclinical cancer stages with approximately the same accuracy as already diagnosed cases. The detection accuracy may vary due to failure in conditioning of dogs, decreasing motivation or confounding factors. The dogs' performance should be systematically checked in rigorous double-blind procedures. Recommendations for methodological standardization have been proposed.
对近十年发表的使用经过训练的狗来识别人类癌症呼吸气味标志物的实验研究进行了分析，并与作者自己的结果进行了比较。已发表的具体研究在实验设置、气味样本类型（呼吸、尿液、肿瘤组织、血清）、样本采集方法、狗的特征和狗的训练方法以及检测灵敏度和特异性方面的结果存在差异。一般来说，可以说经过训练的狗能够以“优于随机概率”的比率将肺癌和其他癌症患者典型的呼吸气味样本与健康人典型的样本区分开来。狗的指示与呼吸样本中2-戊酮和乙酸乙酯的含量呈正相关（分别为r = 0.97和r = 0.85），与1-丙醇和丙醛呈负相关（分别为r = -0.98和-0.87）。作为一种潜在的癌症筛查方法，犬类方法具有一些优点，因为它具有非侵入性、气味采样和储存简单、易于测试和结果解释以及成本相对较低。该方法的缺点和局限性与以下事实有关：仍不清楚狗对哪些化合物和/或其组合做出反应。到目前为止，还无法证实狗能够以与已确诊病例大致相同的准确性嗅出早期临床前癌症阶段。由于狗的条件训练失败、动机下降或混杂因素，检测准确性可能会有所不同。应在严格的双盲程序中系统地检查狗的表现。已提出了方法标准化的建议。
