Overview 

What is tonsil cancer? 

Tonsils are a part of the lymphatic system and are located in the back of our throat.¹ They serve an important purpose as part of the system responsible for defending us against inhaled or ingested pathogens.¹ However, cancer can occur in the tonsils when you are exposed to risk factors, such as smoking, drinking or infection with human papillomavirus (HPV).² Tonsil cancer may not be as common in comparison to other types of cancer, but the number of cases is rising as a result of an increase in HPV infections.^2,4 Symptoms of tonsil cancer include a sore throat that does not heal, difficulty swallowing, and a lump on your neck.⁵ 

Tonsil cancer treatment

Tonsil cancer is diagnosed based on its stage (stages 1 to 4), which indicates the size of the tumour and the extent of its spread. It enables doctors to choose the most suitable treatment, as different stages respond to treatment differently. The following outlines several possible treatment plans for the different stages of tonsil cancer.^2,5 

• Early stage (stage 1 or 2):
  • Surgery
  • Radiotherapy
  • Chemotherapy 

Surgery is typically combined with radiotherapy or chemotherapy.⁵ If the removal of the tumour can cause complications, the patient may undergo a combination of chemotherapy and radiotherapy, which is known as chemoradiotherapy.⁵ 

• Late stage (stage 3 or 4):
  • Surgery 
  • Chemoradiotherapy 
  • Targeted therapy 
  • Immunotherapy 

It is common for radiotherapy to be given simultaneously with cisplatin chemotherapy.² However, if chemotherapy is not suitable for the patient, it can be replaced with targeted therapy or immunotherapy.² 

Treatment for recurrent tonsil cancer 

Can cancer return after treatment? It is possible, which is why cancer patients are closely monitored during and after their treatment.⁶ If there are signs of the cancer returning, there may be treatment plans recommended to help treat or slow the growth and spread of the cancer. The treatment options include:^2,7 

• Surgery
• Targeted Therapy 
• Immunotherapy
• Chemotherapy
• Radiotherapy 

When cancer reoccurs in the same location as the initial diagnosis, it is referred to as localised recurrence. In such cases, surgery may be an option.² However, if the recurrence is not localised or the patient is not fit for surgery, targeted therapy and immunotherapy may be considered, often in combination with radiotherapy or chemotherapy.²

Importance of targeted therapy and immunotherapy 

Targeted therapy and immunotherapy can be very effective in cancer treatment. However, the results vary between patients depending on their cancer type and stage. Despite these challenges, these treatments offer a unique advantage that holds the potential for advancing the future of cancer treatments.^8,9 In this article, we will be covering: 

• Targeted therapy in the treatment of tonsil cancer 
• Immunotherapy in the treatment of tonsil cancer 
• Challenges and considerations 
• Support for patients with recurrent cancer

Targeted therapy in the treatment of tonsil cancer 

What is targeted therapy? 

DNA is like a manual that includes the information our cells need to produce proteins such as enzymes, hormones and antibodies. These proteins are required in several processes in our body, including cell growth and division. 

When this manual contains an error (which is called a DNA mutation), the protein can be assembled incorrectly and therefore cannot function properly, or abnormal amounts of protein are made.¹⁰

In cancer, the malfunctioning proteins are typically those responsible for slowing growth and division, effectively disabling the cell’s brakes. Conversely, the overproduced proteins are those that activate cell growth and division, effectively jamming the cell’s accelerator. Both of these mutations lead to the abnormal expansion of cancer cells.¹⁰ 

This is relevant to the mechanism of targeted therapy, as it works by inhibiting specific genetic mutations or proteins that promote the multiplication of cancer cells.¹¹ 

How does targeted therapy work?

Cetuximab is a commonly used targeted therapy for tonsil cancer. It can attach itself and block the function of a receptor called epidermal growth factor receptor (EGFR).¹² This is important as EGFR helps fuel cancer cell growth.¹³  

Benefits of targeted therapy

Targeted therapies are directed towards the proteins that cancer cells are dependent on for survival. Whilst they can also affect normal cells, the impact is minimal as healthy cells produce lower levels of these proteins. Consequently, targeted therapies cause less damage to healthy tissues and result in fewer side effects in comparison to chemotherapy and radiotherapy.¹¹ 

Immunotherapy in the treatment of tonsil cancer 

What is immunotherapy? 

Immunotherapy consists of several methods that help stimulate immune responses towards cancer cells.¹⁴ What exactly does this mean? 

Our immune system can recognise pathogens, like bacteria, because on its surface it has foreign proteins. All of the cells in our body have our own proteins on their surface so our immune system knows not to attack them. The issue with cancer cells is that they develop from our normal cells, so they can become difficult to recognise as foreign.¹⁵

Without this recognition by immune cells, it is possible for cancer cells to avoid immune responses. Therefore, immunotherapy can be used to help our immune system recognise and kill cancer cells.¹⁴ 

How does immunotherapy work? 

Tonsil cancer can be treated with pembrolizumab or nivolumab. These immunotherapies are known as immune checkpoint inhibitors (ICIs). ICIs work by binding to the protein on the cancer cell that signals the immune cells to stop attacking it.¹⁴ By blocking this protein, the immune system can then effectively destroy the cancer cells.¹⁴ 

Benefits of immunotherapy 

As immunotherapy helps guide our immune system, there is less toxicity experienced by cancer patients when compared with chemotherapy and radiotherapy.¹⁶

Challenges and considerations 

Limitations of targeted therapy

It is important to consider that targeted therapy may not be suitable for everyone. Each individual is exposed to unique risk factors, which influence the randomness of mutations. Since different types of mutations can occur, not all tonsil cancer patients will have an EGFR mutation, meaning cetuximab would not be as effective for them.¹⁷ Additionally, some patients may have a KRAS mutation that causes them to be resistant to cetuximab, resulting in poor responses to cetuximab.¹² 

Limitations of immunotherapy 

Cancer cells can find various ways to avoid destruction by immune cells. One method is causing T cells to become dysfunctional.¹⁸ T cells are a type of immune cell that is required to destroy cancer. Resistance can also be acquired by using regulatory immune cells to suppress immune responses needed to eliminate cancer.¹⁸ This ability to inhibit the functioning of the immune system can negatively impact the effectiveness of treatment. 

Supporting patients and families with recurrent cancer

When cancer returns, it brings back the same worries that patients had from the first diagnosis. It is important to understand that there are other treatment options out there. Continue to stay informed, as treatments will continue to improve. Have an important discussion with your doctor about these treatment plans and how the side effects are different from your first therapy. Keep in mind that you have fought through this once. It can be overwhelming, but there are ways you can cope by finding new activities to do and surrounding yourself with the support of your family. 

Summary

The incidence of tonsil cancer continues to rise as there are more HPV infections. Depending on the stage of tonsil cancer, different combinations of treatments are tailored to each patient. Targeted therapy and immunotherapy are treatment options that are typically employed in managing the growth and spread of advanced and recurrent cancers. These treatments offer precision, resulting in fewer side effects, but it is also important to understand the limitations of these therapies. 

FAQs

How likely is it for tonsil cancer to return? 

It depends on the stage of cancer. The likelihood of cancer returning is lower when the cancer is diagnosed at an earlier stage. For a particular type of tonsil cancer, it is said that 25%-30% of cases occur in the early stages, whereas 50-60% of cases occur in late stages.¹⁹ 

What is the common side effect of cetuximab? 

Changes to the skin, such as rashes, eczema and hyperpigmentation.²⁰ 

What is the common side effect of pembrolizumab and nivolumab? 

For both immunotherapies, tiredness is the most common side effect experienced. Other symptoms include itchiness and decreased appetite for pembrolizumab.²¹ Nivolumab can also cause pain, diarrhoea, and rashes.²²