Good oral hygiene is an essential aspect of overall well-being and health. However, its maintenance during treatment for breast cancer, such as chemotherapy and radiation therapy, can often be overlooked¹. Breast cancer patients undergoing these therapies can frequently experience mouth problems, which left untreated can lead to complications. This blog will explain why breast cancer treatments can cause mouth problems, the most common oral complications, and how to manage these side effects.

Why is oral health important?

Taking care of your teeth and gums by brushing and flossing daily is vital for good oral hygiene. Without this, bacteria can build in the mouth causing bad breath, infections such as tooth decay and gum disease, and tooth loss². Additionally, good oral health can improve your well-being and quality of life. This is because our teeth play an important role in our daily lives allowing us to speak clearly, eat and drink, contributing to our self-esteem and overall happiness³.

Why can breast cancer treatments cause mouth problems?

Therapies against breast cancer can cause damage to the lining of the mouth and salivary glands, impacting the production of saliva⁴. As well as this, therapies that cause a reduction in the number of white blood cells can weaken the immune system⁵. Together, these can upset the healthy balance of bacteria in the mouth, increasing the risk of oral infections and complications.

The most common mouth problems caused by breast cancer treatment include:

1. Oral mucositis

Oral mucositis is the inflammation and ulceration of the mucous lining of the mouth, characterised by red and painful sores⁶. During breast cancer treatment, chemotherapy agents such as 5-fluorouracil (5-FU), anthracyclines (e.g., doxorubicin) and taxanes (e.g., paclitaxel) contribute to oral mucositis because chemotherapy affects the rapidly dividing cells, such as cells of the mouth lining⁷.

2. Xerostomia (Dry Mouth)

Xerostomia, more commonly known as “dry mouth”, is a common side effect of chemotherapy. While chemotherapeutic agents kill cancer cells, they also harm normal cells, including the rapidly dividing cells of the salivary glands⁸. These damaged salivary glands produce less saliva or produce an extra thick saliva, causing dry mouth and difficulties in talking and swallowing (dysphagia)⁹.

Common chemotherapies used in breast cancer that can cause dry mouth include:

• Cyclophosphamide
• Doxorubicin
• Paclitaxel
• Docetaxel

Breast cancer patients have also reported experiencing dry mouth during treatment with hormone therapies including tamoxifen and aromatase inhibitors (e.g., anastrozole, letrozole, exemestane)¹⁰.

3. Gum disease and tooth decay

Reduced saliva production associated with dry mouth can significantly increase the risk of gum disease and tooth decay.

Saliva plays a crucial role in maintaining oral health by¹¹:

• Neutralising acids produced by bacteria – Without saliva, these acids can build up and erode tooth enamel, leading to tooth decay.

• Controlling harmful bacteria- Saliva contains enzymes and proteins with antibacterial properties that help to control the growth of harmful bacteria in the mouth.

• Reducing plaque formation- Saliva helps to wash away particles of food in the mouth which would otherwise lead to plaque formation. Plaque is a sticky film of bacteria which attacks tooth enamel, leading to cavities and tooth decay.

• Maintaining oral pH- Without saliva maintaining the pH level, the mouth can become acidic, favouring the growth of certain harmful bacteria. Also, changes in the pH of the mouth can cause bad breath, changes in taste, and a loss of appetite.

4. Sore/ bleeding gums

Breast cancer treatments can cause damage to the gums, leading to a red and swollen appearance, as well as bleeding when brushing¹². Bleeding gums are a common side effect of chemotherapy as chemotherapy causes a fall in the number of platelets in the blood (thrombocytopenia)¹³. Platelets play an important role in the clotting of the blood.

Chemotherapy and radiation therapy for breast cancer and mouth problems

• Radiation therapy may directly cause the breakdown of the oral tissue and salivary glands⁴.

• Chemotherapies target and kill rapidly growing cells, such as cancer cells. However, the cells lining the mouth also rapidly divide, allowing the oral tissue to regularly repair itself. As a result, anticancer treatments also target the cells lining the mouth. This can result in damage to the mucous lining and salivary glands¹⁴.

• Both healthy and unhealthy bacteria are found in the mouth. Chemotherapy and radiation therapy can damage the lining of the mouth and salivary glands, disrupting saliva production and the healthy balance of bacteria. This can promote the growth of harmful bacteria leading to infections, mouth sores, and tooth decay⁴.

 

How can mouth problems caused by breast cancer treatments be managed?

Preventative measures 

Follow these oral hygiene tips^15/16:

• Use a fluoride toothpaste- Fluoride protects the teeth against decay by strengthening developing enamel on the teeth.

• Don’t use mouthwash containing alcohol- This can irritate your mouth causing it to feel dry.

• Brush your teeth, tongue and gums after every meal to remove food particles. If your gums are sore use an extra-soft/children’s toothbrush and soften the brussels using warm water.

• Gently floss your teeth every night avoiding regions where your gums are sore or bleeding.

• Keep your mouth and lips moist. Use mouthwash or foam to moisten your mouth at least every 2 hours if you’re not eating or drinking normally. Also, regularly apply lip balm.

• Rinse your mouth several times a day with a solution containing^16/17:
  • ¼ teaspoon salt
  • 1 teaspoon baking soda
  • 1 cup (8 ounces) warm water
  • Follow by rinsing your mouth with plain water.

Avoiding triggers¹⁶

• Alcohol
• All tobacco products including smoking
• Foods with high sugar content, (e.g., sweets and fizzy drinks).
• Hot and spicy foods.
• Foods which are sharp and can scrape/cut your mouth, (e.g., crisps).
• Acidic foods and drinks, (e.g., citrus fruits and juices such as orange juice).

These can all cause irritation to your mouth.

Managing mouth problems caused by breast cancer treatments 

Home remedies and products for dry mouth¹⁷:

• Chew sugar free chewing gum to stimulate saliva production.
• Suck on ice cubes throughout the day to provide your mouth with moisture.
• Choose meals which are moist and use sauces to make swallowing easier. Drink sips of water when eating to wash away food particles and aid swallowing.
• Use a humidifier in your home, especially in your bedroom at night, to add moisture to the air and prevent your mouth from drying out.
• Talk to a healthcare professional about medicines that can stimulate the salivary glands or artificial saliva products.

Pain relief:

• Over the counters pain relievers- Ibuprofen helps reduce inflammation and pain.
• Other types of pain relief such as opioids (e.g., Morphine) can be prescribed for severe pain but must be used under supervision of your doctor and with caution due to risk of addiction and possible side effects.
• Your doctor can prescribe mouthwashes containing local anaesthetic if your mouth is very sore. Local anaesthetics, such as Lidocaine (Xylocaine), can be applied directly to mouth sores to numb the area and relieve pain¹⁸.

Professional help:

• Talk with your cancer doctor and dentist about any mouth problems you are experiencing throughout your cancer treatment.
• Work with them to find medicines to help control the pain.

When to see your dentist during breast cancer treatment?

Before starting chemotherapy

If possible, see your dentist 1 month before chemotherapy starts. This will enable your dentist to identify any pre-existing gum problems or tooth decay before treatment starts⁴. Your dentist can also provide you with specialist mouthwashes to help avoid infections during chemotherapy. Additionally, to minimise the risk of infection, your dentist can provide advice on the best ways to keep your mouth clean and healthy.

During chemotherapy

During chemotherapy, it is recommended that you have regular dental check-ups every 6-8 weeks. This will allow your dentist to monitor your oral health and address any emerging issues¹⁹. However, if you are experiencing oral complications, such as mucositis or dry mouth, you may need to visit your dentist more frequently (every 2-4 weeks). This will allow your dentist to help manage your side effects.

After chemotherapy

It is also important to see your dentist after chemotherapy ends. This is because your dentist will be able to assess your oral health, identify any long-lasting effects such as persistent dry mouth or increased risk of tooth decay. Also, your dentist will be able to monitor the healing process, ensuring that mouth sores are healing properly.

  

And thats mouth problems summed up

Maintaining oral hygiene is crucial for breast cancer patients undergoing chemotherapy and radiation therapy, as these treatments can lead to complications like mucositis, dry mouth, gum disease, and sore gums. By following preventative measures such as using fluoride toothpaste, avoiding alcohol-based mouthwashes, and having regular dental check-ups, patients can manage these effects. Effective oral care and consultation with healthcare professionals can significantly improve overall well-being and treatment outcomes.

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Resources

Mouth care | coping physically | Cancer Research UK

Chemotherapy & Your Mouth: What to Know | Colgate®

Mouth care during and after cancer treatment – Overview | Guy’s and St Thomas’ NHS Foundation Trust (guysandstthomas.nhs.uk)

 

References

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