2nd Department of Internal Medicine, Municipal Hospital Darmstadt, Grafenstraße 9, 64283, Darmstadt, Germany.
Toxicology and Chemotherapy Unit, German Cancer Research Center, Heidelberg, Germany.
BMC Cancer. 2021 Aug 13;21(1):917. doi: 10.1186/s12885-021-08651-5.
Lung cancer is the most common oncological cause of death in the Western world. Early diagnosis is critical for successful treatment. However, no effective screening methods exist. A promising approach could be the use of volatile organic compounds as diagnostic biomarkers. To date there are several studies, in which dogs were trained to discriminate cancer samples from controls. In this study we evaluated the abilities of specifically trained dogs to distinguish samples derived from lung cancer patients of various tumor stages from matched healthy controls.
This single center, double-blind clinical trial was approved by the local ethics committee, project no FF20/2016. The dog was conditioned with urine and breath samples of 36 cancer patients and 150 controls; afterwards, further 246 patients were included: 41 lung cancer patients comprising all stages and 205 healthy controls. From each patient two breath and urine samples were collected and shock frozen. Only samples from new subjects were presented to the dog during study phase randomized, double-blinded. This resulted in a specific conditioned reaction pointing to the cancer sample.
Using a combination of urine and breath samples, the dog correctly predicted 40 out of 41 cancer samples, corresponding to an overall detection rate of cancer samples of 97.6% (95% CI [87.1, 99.9%]). Using urine samples only the dog achieved a detection rate of 87.8% (95% CI [73.8, 95.9%]). With breath samples, the dog correctly identified cancer in 32 of 41 samples, resulting in a detection rate of 78% (95% CI [62.4, 89.4%]).
It is known from current literature that breath and urine samples carry VOCs pointing to cancer growth. We conclude that olfactory detection of lung cancer by specifically trained dogs is highly suggestive to be a simple and non-invasive tool to detect lung cancer. To translate this approach into practice further target compounds need to be identified.
肺癌是西方世界最常见的癌症死因。早期诊断对于成功治疗至关重要。然而，目前尚无有效的筛查方法。一种很有前途的方法可能是使用挥发性有机化合物作为诊断生物标志物。迄今为止，已有多项研究训练狗来区分癌症样本和对照样本。在这项研究中，我们评估了专门训练的狗区分不同肿瘤阶段的肺癌患者样本与匹配的健康对照样本的能力。
这项单中心、双盲临床试验得到了当地伦理委员会的批准，项目编号 FF20/2016。狗接受了 36 名癌症患者和 150 名对照者的尿液和呼吸样本的训练；之后，又纳入了 246 名患者：41 名肺癌患者包括所有阶段和 205 名健康对照者。从每位患者采集两份呼吸和尿液样本并进行冲击冷冻。只有新受试者的样本在研究阶段才呈现给狗，随机、双盲。这导致了指向癌症样本的特定条件反应。
使用尿液和呼吸样本的组合，狗正确预测了 41 个癌症样本中的 40 个，总检测率为 97.6%（95%CI [87.1, 99.9%]）。仅使用尿液样本，狗的检测率为 87.8%（95%CI [73.8, 95.9%]）。使用呼吸样本，狗正确识别了 41 个样本中的 32 个，检测率为 78%（95%CI [62.4, 89.4%]）。
现有文献表明，呼吸和尿液样本携带指向癌症生长的挥发性有机化合物。我们得出结论，经过专门训练的狗对肺癌的嗅觉检测很可能是一种简单、非侵入性的检测肺癌的工具。为了将这种方法转化为实践，需要进一步确定目标化合物。
