The air we exhale contains compounds called volatile organic compounds (VOCs), and they’re affected by the food we eat, the bacteria in our gut, and the cells in our bodies. As far back as ancient Greece, doctors have suspected that changes in breath can indicate deeper health issues.

Lung cancer can affect the body in many ways, including how a person’s breath smells — though some people with the condition never notice a change in the odor of their breath. While the topic of lung cancer breath is rarely discussed on MyLungCancerTeam, researchers have long known about the changes in breath smell that happen with lung cancer and other diseases.

Interestingly, as medical technology continues to evolve, there’s hope that a simple breath test at the doctor’s office could promote early detection of lung cancer.

Read on to learn more about lung cancer breath, including why a person with lung cancer may experience changes in breath smell and ways to address it.

Characteristics of Lung Cancer Breath

Different health conditions — including types of cancer — may be associated with different breath smells. For example, people with diabetes often develop fruity-smelling breath because of high levels of ketone (chemicals produced by the liver).

The smell of lung cancer breath has been described as musty, unpleasant, and sweet, like that of rotting fruit or honey that’s fermenting. As noted, these smells can be connected to certain VOCs that build up in a person’s body due to lung cancer.

Everyone has three basic compounds in their breath:

• Acetone
• Isoprene
• Methanol

However, studies show that people with lung cancer have lower levels of these compounds than those without lung cancer. Researchers also have identified up to 100 potential compounds that may be related to the presence of cancer. They’ve found that lung cancer breath is more concentrated in certain aldehydes and alkanes. Pentanal, hexanal, octanal, nonanal, and butanedione are some of the compounds found at higher levels in people with lung cancer.

Smoking Causes Bad Breath

While not everyone with lung cancer smokes or has a history of smoking, smoking is strongly associated with the disease. Anyone who has smoked before knows that it can alter their sense of smell and taste.

Smoking also leaves a smell on your breath that lingers and can be tough to get rid of just by brushing your teeth. This is because smoking dries out the mouth and promotes halitosis, the technical term for “bad breath.” By reducing saliva and disrupting the normal balance of good versus bad bacteria in the mouth, smoking is the second leading cause of halitosis.

Fortunately, quitting smoking reduces a person’s likelihood of halitosis to the same level as people who’ve never smoked.

If you recently cut back on smoking or stopped smoking around the same time you received a lung cancer diagnosis, you may notice your breath smells differently because your sense of smell has improved. It could also be that your breath smells different because it’s no longer affected by smoking.

However, if you still notice foul odors in your breath, it’s a good idea to have a dental checkup and screen for issues like tooth decay.

Other Causes of Bad Breath

Other potential factors that can affect the way your breath smells include:

• Dry mouth (as a side effect of medication)
• Consumption of certain foods like garlic and onions
• Gastroesophageal reflux disease (GERD, also called heartburn)
• Infections of the mouth or sinuses
• Tonsil stones

Body odor and breath smells are health-related concerns. You should never feel embarrassed to discuss your bad breath with a health care professional. They can help you sort out the underlying cause and determine how to get it under control.

What To Do About Breath Changes

Noticing persistent changes in your breath could mean that a shift is happening in your body. While more studies are needed to fully understand what that looks like for people with lung cancer specifically, it’s clear that breath changes are a potential sign of disease.

Unfortunately, there’s no established way to get rid of lung cancer-related breath smells. Following your prescribed treatment plan is the best way to address the underlying medical condition causing breath changes (such as lung cancer itself).

A dentist can help manage any oral health problems contributing to mouth odors with professional cleanings, gum disease treatments, and antibacterial mouthwashes.

Other strategies to improve your oral hygiene include:

• Avoiding sugary or smelly foods
• Brushing your teeth at least twice a day (especially after eating)
• Changing your toothbrush every three to four months
• Chewing sugarless gum to promote saliva
• Drinking plenty of water
• Flossing your teeth daily
• Keeping retainers, mouthguards, and dentures clean

Try to remember when you first started noticing breath odors, as this can be useful information for your dentist. Even if there aren’t any concerns with your teeth, good dental hygiene is important and helps prevent other diseases down the road.

The Future of Exhaled Breath Analysis

Scientists are working on advancing technology to make analyzing breath samples a valid method for diagnosing lung cancer and other diseases.

One example is called the electronic nose (e-nose), a device that measures VOC levels in the breath. While it’s still a relatively new innovation, there’s a lot of excitement about the potential for a noninvasive, quick, and sensitive test to identify the early stages of lung cancer. So far, the research has been conducted only in lab settings, but clinical trials are the next step on the horizon.

Talk With Others Who Understand

MyLungCancerTeam is the social network for people with lung cancer and their loved ones. On MyLungCancerTeam, more than 12,000 members come together to ask questions, give advice, and share their stories with others who understand life with lung cancer.

Have you noticed a distinct odor in your breath since getting diagnosed with lung cancer? How do you manage this symptom? Share your suggestions in the comments below, or start a conversation by posting to your Activities feed.