Multiple studies, reviews, and clinical evaluations demonstrate that trained dogs can detect cancer through the smell of volatile organic compounds found in breath and urine samples with high sensitivity and specificity.
The provided literature strongly supports the claim that dogs can detect cancer through smell. Multiple reviews, empirical evaluations, and meta-analyses (such as papers [0], [2], [5], [6], [7], [9], and [11]) consistently show that trained canines can identify cancer biomarkers in biological samples like breath and urine with high sensitivity and specificity. There are no papers refuting this capability.