Animals and Money: Sniffing to Save Money - Dogs’ Potential in Lung Cancer Screening

Being greeted by a Labrador wagging its tail as one walks into the doctor's office. This could be the future of lung cancer screening. In 2022, lung cancer was the most common cancer type, as well as the deadliest one with 1.8 million deaths globally 1. Since it is harder to cure late-stage lung cancer, early detection of this disease is fundamental to improve survival rates 2. However, available screening methods, such as low-dose computer tomography (LDCT), involve high expenses and other disadvantages, such as the negative impact of radiation 3. A possible alternative screening method could be realized with the help of dogs. Dogs have an extremely good sense of smell, due to a high density of olfactory receptor cells and neurons, nasal airflow modifications and a relatively large olfactory bulb. This enables humans to train dogs to smell the scent of explosives, drugs or wanted criminals 4. Dogs can even be trained to detect diseases, such as diabetes, COVID-19 or cancer, based on the distinct volatile organic compounds (VOCs) people emit. The composition and concentration of the VOCs change with the progression of cancer and therefore can act as a biomarker that can be detected in a non-invasive way 5. This method has been suggested to be more economical than traditional screening methods 3. However, exact numbers seem to be missing. Below, I will compare the expenses for a cancer detection dog with the LDCT method.

To estimate the expenses for a cancer detection dog, I used information based on the costs of diabetes alert dogs and COVID diagnosis dogs. One-time costs, such as acquisition of the dog and specialized training amount to $8,897 USD 8. Daily screening costs of using dogs to detect lung cancer are estimated at $79 USD/ day 9. The running costs for housing and administrative tasks add $35 USD/ day (based on fees for dog boarding). Food, insurance and veterinary care add $1,332 USD annually and costs for maintaining  the dog’s training over time add another $88 USD annually 8,10. Assuming that a dog is used for cancer detection five days a week for five years, a total of $182,879 USD would be spent, or $140 USD per day. Alternative scenarios, where a dog would be used five days a week for only two years, or three days a week for two years, arrive at $232 USD or $333 USD per day. Cancer detection dogs are, on average, used for testing five samples per session 11,12,13,14. Therefore, if dogs were used instead of LDCT (price per screening: $1,130 USD 7) for five screenings per day, $5,317 USD -
$5,510 USD/ day could be saved, depending on the time scenario the dog is used. For an entire five-years period of the dogs’ service, a total amount of $1,7 million USD –
$7,2 million USD could be saved compared to LDCT screening.

However, the calculations are limited and don’t include costs for e.g. standardized dog training, building facilities or extra costs resulting from false diagnosis. Regarding the success rate of dogs in detecting the presence of lung cancer on the basis of breath samples, a mean sensitivity of 78 % and mean specificity of 71.5 % in published studies were found 3. Also, the range was large: for sensitivity between 55.6 % and 99 %, for specificity between 8.3 % and 99 % 14 ,15. Contrary, LDCT shows high accuracy with a sensitivity of 87 % and specificity of 97 % 17. These numbers indicate that detection dogs in lung cancer screening are not fully realizable yet. Therefore, research should aim for standardized dog training methods and further identification of VOCs related to lung cancer 5,16. Still, the calculations show that dogs hold great potential as an alternative and affordable screening method for lung cancer. Introducing these service dogs to healthcare would allow more economically disadvantaged people and low-income countries to have access to lung cancer screening, ultimately saving more lives.

Simon Schäfer 

Issue 30 (PDF)