Treatment Of Throat Cancer

Introduction

Throat cancer is a type of head and neck cancer, where the malignant cells are usually located in the pharynx, larynx, tonsils or vocal cords. Laryngeal cancers generally occur within the inner squamous cells of the vocal cord region of the larynx, which consists of the glottis, supraglottis and subglottis.1 There can be metastasis which means that the cancer can spread through different parts of the body including nearby tissues, the lymphatic system, and blood.  

Studies have shown that frequent alcohol and tobacco abuse is strongly linked to the development of throat cancer, but an HPV (human papillomavirus) infection was also found to be associated with an increased risk of throat cancer (HPV can be transmitted through oral sex).2

The common types of throat cancer are:  

Laryngeal and pharyngeal cancers are the two frequent types, of which pharyngeal cancer is sub-categorised, depending on the location of the malignancy, as: 

  • Hypopharyngeal Cancer which affects the lower part of the throat near the       trachea, 
  • Oropharyngeal Cancer which is associated with the pharynx and tonsils in the middle of the throat, and  
  • Nasopharyngeal Cancer that affects the upper part of the throat, behind the nose.

Symptoms

The signs and symptoms of throat cancer2 depend on the anatomical location of the tumour, for instance: 

  • Difficulty in performing mouth and tongue movements.
  • The appearance of white blotches in the mouth
  • Enlarged lymph nodes can cause swelling, so a lump-like feature could be observed on a patient’s neck; this lump would also progressively get larger with time.
  • Sore throat is a very common symptom of throat cancer that stays persistent throughout the cancer stages, as the cancerous lesions damage the throat causing discomfort and pain for the individual. 
  • Difficulty in swallowing, which can cause weight loss. 
  • Voice changes as many tumours affect the vocal cords making the patient’s voice seem quite raspy and husky.
  • Bloody coughs
  • Nosebleeds
  • Headaches 

Risk factors

It is important to understand the risk factors that contribute to the development of throat cancer, in order to prevent the disease. The main contributing factors are tobacco and alcohol use. Smoking exposes the larynx to carcinogenic chemicals during inhalation which damages the throat tissue. Meanwhile, alcohol makes it easier for carcinogens to be absorbed by the mouth and throat. As these habits are more prevalent among males, throat cancer is more commonly seen in males than females. 

Age is an important risk factor as this disease is a chronic condition. Chronic infection with Human Papillomavirus (HPV) can induce cells to function abnormally, causing them to eventually turn into cancerous cells. Also, individuals who experience Gastro-oesophageal reflux disease (GERD or GORD) are at a higher risk for throat cancer, due to the damage and scarring done to the throat tissues.3

Diagnosis

There are several diagnostic tools available for physicians to test or identify whether or not a patient has developed throat cancer. A clinical examination for abnormal swelling in the neck and monitoring of the signs of potential risk can be performed. Biopsies of lesions from the throat are an accurate method to visualise the malignant cells for a proper diagnosis. These are often obtained during a laryngoscopy procedure. A laryngoscopy also allows physicians to observe the inside of the throat, specifically the voice box (larynx). An additional examination might be an endoscopy, which uses a thin tube which has a built-in lens, called an endoscope that can travel through the trachea to also investigate cancerous tissues. 

There are different types of imaging techniques that are less invasive and allow oncologists to easily view the cancerous lesions on the throat. Magnetic Resonance Imaging (MRI) uses radio waves to create computer-generated images of the body. Computed Tomography, or CT, scans are also often used to diagnose throat cancers, they generate a series of images from different angles using X-ray technology.

Another useful imaging method is a Positron Emission Tomography (PET) scan, the patient would be injected with a radioactive substance to highlight which cells are more active within the throat indicating the presence of cancer cells as they have higher metabolic activity.1

A diagnosis helps categorise cancer into stages, depending on the severity and metastatic level: 

Stage 0 represents a patient with abnormal cell activity in the larynx epithelium, these cells potentially can become cancerous, this stage is also known as carcinoma in situ. 

Stage 1 throat cancer shows cancerous lesions in one area of the larynx, with vocal cords having normal function. 

In stage 2, supraglottis tumours (see introduction) would have spread to nearby tissues like the tongue or vocal cords. If the tumour is based in the glottis or subglottis then cancer would also spread to nearby throat tissues, but here the vocal cords would not function normally.1

Stage 3 laryngeal cancer is characterised by an increased size of the tumour that has affected the entire larynx but has not spread outside the throat region, except for maybe  the associated lymph nodes. The vocal cords are disrupted and this causes significant changes in speech and swallowing.  

The most advanced stage of throat cancer is stage 4. Here, the tumour can appear to be any size, with it being spread to lymph nodes, other organs or parts of the body (e.g. mouth, thyroid or jaw) and can even spread to the other body parts depending on the progression of the tumour.

Treatments

Radiotherapy

Radiotherapy treatment for throat cancer involves using high-energy X-rays or other types of waves to directly eradicate cancerous cells or limit their proliferation. A rotating radiation machine would be placed externally around the head and neck to aim its high-energy beam at the location of the tumour, delivering radiation from different angles to tackle the entire area of cancer. A mesh mask is placed to hold the patient’s head in a fixed position throughout the treatment.1

Another form of radiation therapy involves using a smaller daily dose administered twice a day, sometimes by injecting a radioactive substance into a vein, to avoid using high-energy waves for patients who are physically too weak to undergo heavy radiation doses. 

Unfortunately, radiation has many side effects which start to appear days after the initial treatment. Because the treatment is directly aimed at the throat, the patient’s mouth and throat are prone to becoming sore leading to the development of mouth ulcers and dry mouth. In addition, the patient’s saliva starts to appear thicker and stickier, which accumulates in the mouth and throat. General side effects like weakness and headaches are very common in all treatments of throat cancer and are also present following radiotherapy.

Surgery

Another common treatment to get rid of throat cancer is surgery to physically remove the cancerous tissue; there are many types of surgeries available depending on the anatomical location of the tumour. A cordectomy removes the vocal cords of the patient, whereas a laryngectomy allows removing either the whole or partial regions of the larynx and a thyroidectomy is the removal of parts of the thyroid gland. 

The surgeries can also be performed via a laser beam to make bloodless incisions.1  But, during the post-surgery phase, other treatments might still be administered to the patients to reduce the chances of recurrent cancer. The surgery carries a lot of risks no matter the complexity of the patient’s case, with adverse effects such as blood clot formation, pathogenic infections and anaesthesia complications. There is also a high risk of the patient losing their voice if the surgery requires the removal of cancer in the vocal cords.

Chemotherapy

Chemotherapy is frequently used alongside radiation therapy when treating throat cancer. The treatment consists of using drug treatments to limit the growth of the cancer by killing the cells or interfering with their replication cycles

The drug is administered via several routes like the mouth, vein or muscle injections. The medicine is given in weekly cycles to allow tolerance and recovery of the patients. The drugs function by attacking fast-dividing cancer cells. Examples of the drugs used are:

  • Cisplatin
  • Carboplatin
  • Docetaxel
  • Paclitaxel 

Because chemotherapy is very toxic to cells it can cause extreme side effects, such as severe weakness, and weakening of the immune system rendering the body susceptible to infections and easy bruising. Other recurrent effects include weight loss, nausea, hair loss and diarrhoea.

Immunotherapy

Immunotherapy is a form of treatment that utilises an individual’s immune system to attack throat cancer. 

Cetuximab

The monoclonal antibody Cetuximab is used as an immunotherapeutic agent for another form of throat cancer treatment. This immune protein will target blocking the activity of the EGF receptors (EGFR) of cancer cells to halt or slow the proliferation of cancer cells. This form of treatment can also be combined with radiotherapy in complex and late-stage cases of throat cancer. The side effects of the drug include but are not limited to, uncomfortable skin conditions on the face and chest areas, such as acne and rashes; fever, weakness, allergic reactions and gastrointestinal issues.4

Pembrolizumab

Another form of immunotherapy drug is Pembrolizumab, which targets a protein present on immune cells, specifically T cells. It acts by improving the immune system’s responses, to sustain the immunogenic response against the cancer cells, which may eventually lead to a reduction in the size of the tumour within the throat. The drug is administered via intravenous infusions every couple of weeks. Side effects directly caused by Pembrolizumab are coughs, diarrhoea, itchy rashes, constipation, and muscle and joint pain.

How is a Treatment Plan Determined?

For the oncologist to plan out an efficient treatment option for an individual, they have to take into account many contributing factors. 

The anatomical location of the cancerous lesions is essential to understand what method would be best when approaching cancer within the throat. Furthermore, each patient’s case is unique as not all patients would be able to tolerate the same type of treatment. 

Due to age, medical history or even genetics, some treatments are more or less beneficial to a particular patient. For that reason, the cancer specialist needs to be able to specifically diagnose which stage of throat cancer is a patient experiencing, because the more advanced cancer has become, the more likely it could have spread to other parts of the body. So, stronger treatments may need to be administered. 

Generally speaking, stage 1 and 2 laryngeal cancers are treated without the need to remove the whole larynx. Most patients would undergo radiation therapy in this stage or even partial laryngectomy to remove the cancerous lesions in the throat. 

For more progressed (later) stages of throat cancer, the major treatment methods would include surgery, radiotherapy and chemotherapy. Most of the surgeries would, unfortunately, involve the total removal of the larynx and possibly even nearby lymph nodes, because due to metastasis the lymph node is a common tissue invaded by active throat cancer cells.

The combination of chemotherapy and radiation in chemoradiation is a very strong treatment, however, it is not tolerable by all patients, and it potentially can cause irreversible damage to the larynx and nearby tissues like the thyroid gland. 

Despite that, with advanced or end-stage cancers the treatment goals are to slow down the growth of cancer as it is unlikely that the physicians would be able to eliminate all the tumours present within the body.

Quality of Life after Throat Cancer Treatment

The symptoms associated with throat cancer and its treatments significantly reduce a person’s quality of life. There need to be initiatives taken to support cancer patients as well as survivors to cope with their prognosis. 

Many patients can undergo speech treatments at rehabilitation centres to restore the function of the damaged tissues. 

Throughout the patient’s treatment journey, an important aspect to focus on is pain management.  Drug administrations like painkillers or medical cannabis could help people cope with the side effects of therapy including pain, nausea, and fatigue. Moreover, any disease takes a  toll on a person’s psychological well-being. Therefore, it is vital to give patients access to psychologists and therapists to prioritise their mental health.1

Summary

Throat cancer affects the pharynx or larynx region of the throat, however, it may also manifest in the oesophagus or thyroid, which are also considered forms of head and neck cancer. 

The main contributing factors to developing throat cancer involve heavy usage of tobacco and alcohol over a long time, but more recently the role of HPV infections has become the main contributor to throat tumours. Common symptoms include: throat pain, coughing up blood, abnormal voice changes, extreme weight loss and lumps on the neck. 

The disease can be diagnosed via various methods of imaging techniques and blood tests, but a biopsy usually is the best method of confirmation. Depending on what stage cancer has advanced to, either one or multiple treatments in conjugation would be governed for the patient. The most common treatments are removed by surgery, X-ray radiation therapy, chemotherapy and forms of immunotherapy drugs.

References

  1. Throat (Laryngeal) Cancer - Dana-Farber Cancer Institute | Boston, MA [Internet]. [cited 2022 Sep 4]. Available from: https://www.dana-farber.org/throat-laryngeal-cancer/.
  2.  Throat Cancer | Memorial Sloan Kettering Cancer Center [Internet]. [cited 2022 Sep 4]. Available from: https://www.mskcc.org/cancer-care/types/throat.
  3. How Can I Get Throat Cancer? | Throat Cancer Risk Factors [Internet]. [cited 2022 Sep 4]. Available from: https://www.cancer.org/cancer/laryngeal-and-hypopharyngeal-cancer/causes-risks-prevention/risk-factors.html.
  4. Targeted Therapy for Throat Cancer | Laryngeal Cancer Targeted Therapy [Internet]. [cited 2022 Sep 4]. Available from: https://www.cancer.org/cancer/laryngeal-and-hypopharyngeal-cancer/treating/targeted-therapy.html.

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Faisal Badri

BSc in Applied Medical Science, Biomedical Sciences, General, University College London

Faisal is a biomedical student with a strong interest in clinical science treatments who is currently the president of the Emirati Society.

He is an experienced Strategy intern and Scientific and Medical Writing Intern.

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