A Labrador Retriever who has been trained to sniff out colorectal cancer was almost as accurate as a colonoscopy in a study being reported by Bloomberg that suggests less invasive tests for the disease may be developed. The study showed that the dog was proven to be at least 95% as accurate as colonoscopy when smelling breath samples, and 98% accurate when sniffing stool samples, according to the study, published today in the medical journal, Gut. The dog’s sense of smell was especially effective in early-stage cancer, and could discern polyps from malignancies, which colonoscopy can’t.