Cancer Smells: Research, Diagnosis, Treatment Effects

Cancer cells may cause body odors, but not odors that most people will notice.  While some studies show dogs may be able to detect cancer smells, researchers are exploring the possibility of detecting the odor of cancer to help reach a diagnosis sooner.

While people probably can’t detect cancer by smell, you might notice changes in body odor that occur with cancer treatment.

This article discusses why cancer has an odor and how it can be detected. It will also discuss changes in body odors from the cancer treatment itself. 

What Causes Cancer Odors?

Scientists are still trying to determine exactly what causes cancer to have a smell. Cancer is essentially a process in which cells don't divide properly (the cells multiply too quickly and don't die when they're supposed to). This abnormal process can lead to the death of other healthy cells and changes in the body that may produce volatile organic compounds (VOCs).

These VOCs are byproducts of some biological processes in the body. Things like infection, inflammation, and even cancer, can produce VOCs, which can be sensed in the breath or urine.

VOCs have been detected in the breath and urine samples of people who have cancer, as well as in other body fluids. One study found that many VOCs were present at different levels for a variety of cancers, including breast, prostate, lung, and bladder to name a few. 

In the study, the levels of certain VOCs found in people with cancer were higher than in those without cancer.

It’s important to note that there are currently no standard procedures to test for VOCs, nor has there been a proven clinical benefit to doing such tests.

One of the VOCs that may produce a scent is polyamine. This compound is often produced at higher levels in cells that are dividing quickly, which cancer cells do. Polyamines can be detected in the blood and urine of people with cancer.

If cancer is close to the surface of the skin and has caused an ulcerated mass to form, this can become a breeding ground for bacteria. The infection that results can then cause a foul odor.

Can Body Odors Help Diagnose Cancer?

It's well known that dogs have an incredible sense of smell. For years, humans have recruited dogs for their heightened sense of smell to sniff out drugs and weapons, and to aid in the search of missing people.

Researchers are now wondering if dogs might also be able to sniff out cancer in humans. Studies have shown that dogs have the potential of smelling VOCs significantly better than humans.

In these studies, dogs were trained to detect the scent of cancer, often using breath or urine samples. Although it isn't exactly known which VOC in cancer the dogs are able to smell, studies have found they've had some success in detecting cancer.

In one study, dogs were provided with urine and breath samples. Dogs with access to both urine and breath samples were able to correctly detect cancer in 98% of the samples. Dogs with access to urine samples alone were able to correctly identify 87% of samples with cancers, and dogs with access to just breath samples correctly identified cancer in 78% of the samples.

It's important to note, however, that the study doesn't mention whether the dog identified VOCs in people without cancer.

How Does Cancer Treatment Cause Body Odors?

The average person is not able to detect the smell of cancer, but they may notice changes in the odor of body fluids caused by treatment for cancer. 

The sense of smell may be more sensitive to people undergoing cancer treatments also. Strong odors, such as those in foods, are especially offensive. Sometimes people are so sensitive to smell, they become easily nauseated.

Causes

Side effects of chemotherapy can lead to alterations in the senses of taste and smell. This is a common side effect of many chemotherapy medications and regimens used to treat many types of cancer.

As chemotherapy is processed throughout the body, it can produce a variety of odors that can come through the skin, urine, feces, or sweat.

Strong chemotherapy drugs may cause urine to change color and have a strong or unpleasant odor, and if you’re dehydrated it could be even worse.

Another side effect of chemotherapy can be dry mouth. The powerful chemotherapy drugs can affect cells in the mouth causing mouth sores, bleeding gums, and tongue irritation. These side effects can lead to bad breath.

People may also develop bad breath if they have nausea and vomiting associated with chemotherapy.

Coping  With Body Odor From Cancer Treatment

Some side effects of chemotherapy and other cancer treatments are unavoidable. However, there are some steps you can take to help remain as comfortable as possible. 

If your sense of smell is sensitive, and possibly causing nausea, avoiding being around smells that you're sensitive to can be helpful. To manage the smells that come from food, the following can be helpful:

• Try foods that can be eaten raw
• Don’t eat in rooms that are too warm
• Eat foods cool in temperature
• Avoid foods that have strong odors, such as fish or onions

For those living with cancer who have ulcerated tumors that are possibly infected and causing a foul odor, talking to your cancer care team about ways to decrease the odor can be helpful. Sometimes medications can be given, such as antibiotics, to help decrease the odor.

Practicing proper skin hygiene can help you avoid infection, and subsequently, foul odor.

Summary

There can be odors from the VOCs associated with the development of cancer in the body that may be detected by specially trained dogs. Yet, this isn't the standard of care and more research needs to be done. These scents are generally undetectable by humans, though, and scientists are working on ways to measure these VOCs in urine and breath samples. 

The chemotherapy used to treat cancer may also cause a change in the smell of someone’s urine, breath, feces, and sweat. 

A Word From Verywell

It may be strange to think that cancer can have a smell to it, but it’s true. Research is ongoing to determine the possibility of dogs being used to sniff out cancer while it's at an early stage.

If you’re living with cancer and have concerns about any odor changes in your body, be sure to talk to your cancer care team.