A prospective trial for breast cancer diagnosis by canine odorology

Breast cancer (BC) is a major health concern affecting millions of women worldwide. This study (NCT04217109) explores canine odorology as a method for identifying BC using patient sweat samples. To collect the sweat samples, the night before biopsies, a compress is applied to the affected breast and the sample is subsequently presented to two trained dogs during the training or testing sessions. A positive cancer detection is indicated if a dog halts in front of the compress. A total of 181 patients participate, 107 with breast cancer (82 invasive and 25 in situ) and 74 with benign lesions. Sensitivity (Se) is 68% and specificity (Sp) 27% for a single randomly selected dog. When at least one dog marks a sample, Se rises to 80.4% but Sp drops to 21.6%. If both dogs mark it, Se is 48.6% and Sp 45.9%. Results show limited ability to distinguish benign from malignant lesions. Dogs perform best with mixed samples but struggle when all are negative, with variable responses between dogs. Identifying BC-specific volatile compounds may improve accuracy.