Who says you can’t teach an old dog new tricks? Japanese researchers say they’ve successfully trained an 8-year-old female black Labrador retriever to sniff out colon cancer on the breath of a patient.

Published Monday by the digestive health journal Gut, the study adds to previous research suggesting that dogs can be useful for cancer detection. Studies over the past few years have shown that dogs can detect melanoma, bladder, lung, ovarian, and breast cancer, also by sniffing the breath of cancer patients.

Their amazing sense of smell allows dogs to identify chemicals that are diluted as low as a few parts per trillion. It’s why we rely on man’s best friend to sniff out bombs and drugs at airports.

In the current study, the black Lab sniffed 33 breath samples from patients with colon cancer and 132 samples from healthy controls, about half of whom had benign colon polyps. The dog sniffed each sample, five to a group, and was trained to sit in front of the one that had cancer.

She correctly identified those who had cancer 91 percent of the time — correctly distinguishing between cancerous and benign polyps — and was correct in excluding healthy samples 99 percent of the time when compared with findings on a colonoscopy.

When the dog was given watery stool samples to sniff instead, she was able to find 97 percent of the cancers with the same specificity rate of 99 percent. The fecal occult blood test, another routine colon cancer screening method that checks for blood in the stool, detected about 70 percent of the cancers and had a specificity rate of 85 percent.

If you’re looking to get out of a colonoscopy, however, no such luck — at least for a while. The dog-sniffing method is hardly ready for prime time, given the small amount of samples that have been tested.

There’s also the matter of training the dogs. “It may be difficult to introduce canine scent judgment into clinical practice,’’ write the study authors, led by Dr. Hideto Sonoda of Kyushu University at Fukuoka, “owing to the expense and time required for the dog trainer and for dog education.’’

- By Deborah Kotz （The Boston Globe）

训练的狗嗅着了98％的准确度与结肠癌

一项新的研究表明，这是一个训练有素的拉布拉多猎犬嗅出癌症能够检测为大肠癌结肠镜检查几乎准确。

在这项研究中，九州大学的研究人员训练一个8岁的女拉布拉多猎犬名为海洋谁是给予306例呼吸和粪便样本，收集他们接受结肠镜检查前的权利。最近有48例被诊断出患有肠癌，其他258人无论是从另一个大肠疾病的痛苦或已经战胜了癌症，或者是健康的。在她的评估，海洋，至少95％是确定准确的大肠镜检查癌症，98％的正确嗅粪便样本时，研究人员发现。她最能当场早期癌症，并能辨别恶性肿瘤，其中甚至不能做结肠镜检查息肉。这项研究发表在医学杂志肠道 。

特雷弗洛基特，与英联邦科学和工业研究组织在澳大利亚肠癌研究员说，“早期癌症的检测是真正的肠癌诊断的圣杯，因为手术可以治愈多达90％的患者早期谁现在的舞台疾病。“虽然狗不能用于这一目的，研究人员认为，电子气味探测器可开发基于这一原则。 “这项研究表明，特定癌症的气味确实存在，”研究人员写道，在“这些气味物质可能成为筛选的有效工具。”

根据主要从手术在医学研究生院在九州福冈大学，目的是找出气味是否可以成为大肠癌筛检的有效工具研究部研究员博士Hideto园田。如乳腺癌，胃癌和前列腺癌等癌症时，园田说，“犬产生气味的判断，以及这些癌症患者的正确答案，这表明可能存在着共同的气味不同癌症类型。”

这项研究发表评论，博士特德Gansler，医疗内容主管在美国癌症协会说，“这项研究增加了一个展示的其他出版关于膀胱癌，肺癌和乳腺癌的文章类似的结果少数”，为最近会议介绍有关前列腺癌。下一步是发现特定化学物质与结肠癌有关，或与其他类型的癌症，Gansler说补充说，“一旦做到这一点，科学家将尝试开发实验室测试，检测为癌症筛查方法，这些化学品的潜力。 “

博士弗洛里亚努马尔凯蒂，是临床外科助理教授，结肠和直肠外科住院医师项目主任米勒在美国迈阿密大学医学院，他说，“方向应该是在寻找刺激的那只有机化合物反应的研究来。“


[论文摘要] Sonoda H, Kohnoe S, Yamazato T, Satoh Y, Morizono G, Shikata K, Morita M, Watanabe A, Morita M, Kakeji Y, Inoue F, Maehara Y.  Colorectal cancer screening with odour material by canine scent detection. Gut. 2011 Jan 31

Objective Early detection and early treatment are of vital importance to the successful treatment of various cancers. The development of a novel screening method that is as economical and non-invasive as the faecal occult blood test (FOBT) for early detection of colorectal cancer (CRC) is needed. A study was undertaken using canine scent detection to determine whether odour material can become an effective tool in CRC screening. Design Exhaled breath and watery stool samples were obtained from patients with CRC and from healthy controls prior to colonoscopy. Each test group consisted of one sample from a patient with CRC and four control samples from volunteers without cancer. These five samples were randomly and separately placed into five boxes. A Labrador retriever specially trained in scent detection of cancer and a handler cooperated in the tests. The dog first smelled a standard breath sample from a patient with CRC, then smelled each sample station and sat down in front of the station in which a cancer scent was detected. Results 33 and 37 groups of breath and watery stool samples, respectively, were tested. Among patients with CRC and controls, the sensitivity of canine scent detection of breath samples compared with conventional diagnosis by colonoscopy was 0.91 and the specificity was 0.99. The sensitivity of canine scent detection of stool samples was 0.97 and the specificity was 0.99. The accuracy of canine scent detection was high even for early cancer. Canine scent detection was not confounded by current smoking, benign colorectal disease or inflammatory disease. Conclusions This study shows that a specific cancer scent does indeed exist and that cancer-specific chemical compounds may be circulating throughout the body. These odour materials may become effective tools in CRC screening. In the future, studies designed to identify cancer-specific volatile organic compounds will be important for the development of new methods for early detection of CRC.