The relationship between humans and dogs became intertwined thousands of years ago and the two species have been inseparable ever since. Living alongside a dog brings a great variety of benefits for our body and mind: for example, it helps combat loneliness and depression, reduces the risk of heart attacks and halves the likelihood of developing allergies, it is good for the immune system and for the heart, and it helps children become more sensitive and compassionate. Dogs, however, do not merely enrich our lives — they can literally save them. These animals are, in fact, capable of detecting the presence of tumours thanks to their extraordinary sense of smell.

How dogs sniff out tumours

It is a relatively recent discovery and no detailed studies yet exist, but it is now clear that dogs are able to detect the presence of neoplasms by smell. In particular, dogs appear to be capable of sensing the distinctive odour released by tumour cells.

Better than a machine

The accuracy with which dogs identify various types of tumour is impressive, and is well above 90 per cent, making them often more reliable than most of the equipment currently found in hospitals.

The story of Liù

Liù is a female German shepherd belonging to the Italian Army who has recently come to public attention for her talent in detecting the onset of cancer before the disease has yet developed. Liù has worked in the urology department of the Humanitas hospital in Castellanza, in the province of Varese, for five years, and specialises in identifying prostate tumours. By sniffing patients' urine samples, the dog detects the presence of the tumour, and 98 per cent of the diagnoses made by Liù have proved correct. According to the doctors at the Lombard hospital, Liù's nose has demonstrated that the tumour possesses a particular molecule that a dog's sense of smell can identify. The goal now is to track down this molecule and succeed in isolating it, so as to push diagnoses ever earlier and focus on prevention.

Dogs for people with diabetes

The medical abilities of dogs are not, however, a novelty — these animals have long been employed to assist people with diabetes and epilepsy. That incredible calculator of olfactory information that is the dog's nose is also capable of sensing hypoglycaemia and epileptic seizures before they occur. Now widely established in the United States and the United Kingdom, diabetes alert dogs (DADs) are trained to alert their handler when they detect the smell of hypoglycaemia and to bring their owner the emergency kit.